Preparing to order seeds

Preparing to order seeds: 6 steps + 3 extra tips

Leeks grow slowly. Sow in March to have seedlings this size in May. Order seed soon! Photo Pam Dawling

There are lots of new gardeners now, as a result of the pandemic causing people to stay at home, cook more and want more food security without going inside grocery stores. Maybe last year you bought packets of seeds in a hurry, either online or off a rack in as store. Maybe you hope your garden will go more smoothly this year and I’m here with this blog post to help you.

Or perhaps you are a new professional grower, seeking to improve your game. Or an established one, looking to hang in there by farming smarter in these hard times.

‘Tis the season for garden planning. Inventory your seeds left from last year, peruse the catalogs and prepare your seed orders. The earlier you get them in, the more likely you are to get the varieties you want, before anything is sold out. Be prepared, note your second choice, and fend off disappointment!

Vates kale seedlings for bare-root transplanting.
Photo Pam Dawling

I have a course on garden planning for home gardeners, on the Mother Earth Fair Online. It consists of eight half-hour workshops, covering all aspects of garden planning from clarifying your goals, choosing crops, making maps of what will go where, planning when you want to harvest, determining how long your rows will be and how much seed to order, deciding when to plant and scheduling everything to make the year go smoothly. There are also workshops on ways to pack more in, and how to be prepared for things that don’t go according to plan!

Mother Earth News Fair

Commercial growers and energetic home growers will also be interested in the information on garden planning in my book Sustainable Market Farming.

I have a couple of slideshows on SlideShare.net,

See Crop Planning for Sustainable Vegetable Production 2019 Pam Dawling

To view it full screen, click the diagonal arrow in the lower right.

For long-term soil health and sustainability, think about crop rotations. See Crop rotations for vegetables and cover crops 2014, Pam Dawling

Buckwheat seedlings. Buckwheat is our quickest easiest summer cover crop.
Photo Pam Dawling

 First, a basic 6 steps of garden planning

  1. See How to Decide Which Crops to Grow.

Think about what you grew last year, and whether you want the same again. Think about what you wished you’d grown. Every year we try to introduce a new crop or two, on a small scale, to see if we can add it to our “portfolio.” Some-times we can successfully grow a crop that is said not to thrive in our climate. (Brussels sprouts really don’t). We like to find the varieties of each crop that do best for our conditions. Later we check how the new varieties do compared with our old varieties. We use heirloom varieties if they do well, hybrids if they are what works best for us. We don’t use treated seeds or GMOs, because of the wide damage we believe they do. For ideas of what you might grow, see our Twin Oaks Harvest Calendar by Crop.

Sowing Rainbow Chard. in a Winstrip tray
Photo Pam Dawling

2. Are any of your leftover seeds OK to keep?

See making an inventory, and Ordering seeds! Seed Viability Many seed catalogs include information about seed longevity, and so does Nancy Bubel in The Seed Starters Handbook. Frank Tozer in The Organic Gardeners Handbook has a table including minimum, average, and maximum.

Seeds stored in glass jars
Photo courtesy of Monticello

A simplified version of how long to keep seeds is as follows:

  • Year of purchase only: Parsnips, Parsley, Salsify, and the rarer Sea Kale, Scorzonera
  • 2 years: Corn, Beans and Peas of all kinds, Chives, Dandelion, Martynia, Okra, Onions,
  • 3 years: Asparagus, Carrots, Leeks, Rutabagas, Turnips,
  • 4 years: Artichokes, Basil, Cardoons, Chard, Peppers, Pumpkins, Spinach, Squash, and Watermelons,
  • 5 years: Beets, most Brassicas, Celery, Celeriac, Chicory, Cucumbers, Eggplant, Endive, Lettuce, Muskmelons, Tomatoes,

Rather than deteriorating with age, some very fresh seed has a dormancy that needs to be overcome by chilling (lettuce).

The fuller story is that storage conditions make a big difference. Keep seed cool, dark, dry in airtight, mouseproof containers.

An old hand-drawn map of one of our garden areas.
Image Pam Dawling
  1. How Much of What to Grow?

Make a rough map of your garden space and see what will fit. Remember you can plant a later crop in the same space after an earlier one finishes. See below for more info on quantities of potatoes and garlic, two staples.

  • How Much Garlic to Plant

A yield ratio of 1:6 or 7 seems typical, and makes complete sense when you consider you are planting one clove to get a bulb of 6–7 cloves. Divide the amount you intend to produce by six to figure out how much to plant. For large areas 750–1,000 lbs/ac (842–1,122 kg/ha) are needed for plantings in double rows, 3″–4″ in-row (7.5–10 cm), beds 39″ (1 m) apart. For single rows, 8 lbs (3.6 kg) of hardneck or 4 lbs (1.8 kg) of softneck plants about 100′ (30 m). In the US, one person eats 3–9 lbs (1.4–4.2 kg) per year.

Music hardneck garlic.
Photo Southern Exposure Seed Exchange
A row of potato seed pieces ready to cover.
Photo by Wren Vile
  1. How Much Seed to Order?

Hopefully you kept some kind of record on whether the amount you bought last year was enough. When we figure out how much seed to order we add in some extra for some things – crops that can be difficult to germinate, or we really don’t want to cut too close. We add 20 percent extra for most crops, but only 5 percent for kale, 10 percent for onions and collards and 30 percent for melons. These numbers are based on our experience – yours might be different. We also know which seed we can buy in bulk and use over several years. This gives us an additional security against poor germination, or plagues of grasshoppers or caterpillars. For me, a big bag of broccoli seed for each of our main varieties gives some kind of warm glow of horticultural security! Buying too much either leads to wasting money (if we throw it away) or wasting time and money (if we sow old seed that doesn’t come up well, then have a crop failure).

If you use spreadsheets, see my post Cooking Greens in December Special Topic: Ordering Seeds.

Here’s a helpful table of 1000 Seed Weight for 13 crops. Another of the challenges with seed ordering is converting between grams, ounces and seed counts – have your calculator at the ready, or easier still, just type “Convert ½ oz to grams”into your search engine.

 

  1. Choosing varieties.

See How to read seed catalogs for tips on getting what you really want by paying attention to what’s in the small print and what isn’t mentioned. We carefully look for varieties that offer the flavor, productivity and disease resistance we need. The catalogs are starting to appear in my mail box. The early bird catches the preferred varieties! The main companies we order from are Fedco Seeds, Johnny’s Selected Seeds and of course, Southern Exposure Seed Exchange. We like SESE for regionally adapted varieties, Fedco for great prices on bulk sizes, and Johnny’s for some varieties we really like that aren’t available from the other two.

 

  1. Formatting and placing seed orders

We grow lots of different crops, so we make a spreadsheet, and include columns for the name of the supplier we buy each variety from (we just use the initial), the item number in the catalog, the packet size and the price. (Be careful though, if you carry this information over from year to year – prices change.) Once we have composed our total seed order, we sort the orders by the name of the supplier. Then we can calculate the total price for each supplier. This also gives us the opportunity to look at price breaks for large orders and move an item from one supplier to another, if that makes sense. At this point we usually make a cup of tea and reward ourselves with an “impulse buy” or two, if that doesn’t push us up into a higher shipping cost bracket or blow the budget. We place our orders online these days, nice and early, to increase the chances of getting exactly what we want.

Here are a few more thoughts on crops to consider:

  1. Insurance crops that are there when you need them

Young Bright Lights chard.
Photo Pam Dawling

For an overall sense of success, grow some “Insurance Crops”. These are reliable vegetable crops that grow without much attention and quietly wait until needed. Chard is one of those. We sow chard in April, after the early spring rush. We plan for it to provide us with leafy greens in the summer, after the brassicas have bolted. We prepare a bed, unroll hay mulch over it, then make “nests” in the hay for planting. Nests are holes in the hay down to soil level, at each spot where we want to plant. After transplanting. we water and tuck the hay tight around the plants to keep the weeds at bay. Some years there isn’t much demand for chard and we just leave it growing. If we need it, there it is with a generous supply of leaves. If we ignore it, nothing goes wrong. It’s worth having some crops like this in the garden, to help ensure there’s always something to eat.

Malabar spinach.
Photo by Southern Exposure Seed Exchange

One year we grew Malabar spinach and it played a similar role: hot weather leafy cooking greens. Malabar can be used when small for salads, or when larger for cooking. It wasn’t hugely popular in either role, but it was beautiful. To be fair, I don’t think we did the best by it. Because it was new, and because it had the word “spinach” in its name, some cooks served large leaves for salad. Alone. I don’t recommend that.

Purple Pod asparagus bean,
Credit Southern Exposure Seed Exchange

Another insurance crop for us is asparagus beans, also known as yard long beans. Once trellised, the plants need no attention, other than regular picking. If not picked, the pods grow puffy and useless, so this is not a crop to ignore for too long. Asparagus beans are related to southern peas (cowpeas), and are more resistant to Mexican bean beetles than regular green beans are. They do need trellising, but once you’ve done that, the same plants will feed you all season. Very little seems to trouble them.

West Indian gherkins on a trellis.
Photo by Nina Gentle

While we’re on the topic of crops that do need trellising, but can then produce all season, I’ll add in the West Indian gherkins. I found I did need to tuck these plants into the netting, so they weren’t work free. But the plants were disease-free and very productive. If you have trouble with regular pickling cucumbers, you might sow some of these as well, to be sure of being able to have something to pickle.

Another insurance crop is Tokyo bekana, or its cousin Maruba Santoh in late summer as a substitute for lettuce. It can be hard to germinate lettuce in hot weather, but these tender brassicas germinate under hot conditions and produce fast-growing very tender leaves with crunchy stems. Some people don’t know they’re not eating lettuce!

Tokyo bekana and spinach in October.
Photo Wren Vile

Senposai is a cooking green that does well in spring and fall outdoors, and in our hoophouse in the winter. It’s fast-growing, productive, disease-resistant, easy to cook and delicious to eat.  In spring it needs an early start in our climate, so that it has time to be productive before it bolts. In fall it’s cold-hardy down to 12F.  Its Achilles Heel is that it can really attract Harlequin bugs! We did spend time every day for a while squashing the bugs on the senposai leaves, and we made a difference in the number of bugs.

Well, I hope this has given you some thoughts about ordering seeds of some insurance crops for next year, when you plan your seed order.

  1. VEGETABLE CROPS THAT OFFER FAST RETURNS

Because things can go wrong in agriculture, (we are, after all, not in control of the universe!) I like to have on hand seeds for fast-growing crops that can fill unexpected gaps.

Some Eat-All Greens in early November.
Photo Lori Katz
  1. Eat-All Greens

Carol Deppe, in her delightful book The Tao of Vegetable Gardening introduces us to the concept of Eat-All Greens. Carol grows these by broadcasting seed of one of her carefully chosen greens crops in a small patch. When it reaches 12″ tall, she cuts the top 9″ off for cooking, leaving the tough-stemmed lower part, perhaps for a second cut, or to return to the soil. I wanted to try this idea in Virginia, where the climate is fairly different from the Pacific Northwest where Carol lives. I decided fall was a promising time of year to try this scheme, as our spring planted greens only have a short season before they bolt. And summer is too hot, winter too cold. . . We sowed in mid-September.

These can also be insurance crops, in that, if you don’t need them, you can cut and compost them, to let fresh leaves grow. I wrote three posts on Eat-All Greens, because they were such fun and so productive

Book Review: The No-Till Organic Vegetable Farm, Daniel Mays

Book Review: The No-Till Organic Vegetable Farm: How to Start and Run a Profitable Market Garden That Builds Health in Soil, Crops, and Communities 

Daniel Mays, Storey Publishers, 2020. 230 pages, color photos throughout, $24.95.

The No-Till Organic Vegetable Farm is a great help to those moving towards more No-Till. This book is full of practical details, and efficient and effective no-till practices, such as how to manage large tarps. This is also a beautiful book. The photos are crisp and inspiring, the drawings clear and informative, the charts well organized and easy to use. The aerial photo shows a poster-farm! Frith Farm is a small-acreage vegetable farm using raised beds, in the style of Jean-Martin Fortier, Ben Hartman, Curtis Stone and others. “No-till human-scale farming is about so much more than avoiding tillage.” Here we can learn about healthy soil, high productivity, fewer weeds, lower costs and a more natural way of growing food.

We have had several new books on no-till in the past year or so. I have reviewed Bryan O’Hara’s No-Till Intensive Vegetable Culture, and Andrew Mefferd’s Organic No-Till Farming Revolution: High-Production Methods for Small-Scale Farmers. Any reduction in tillage is a good step: you don’t have to commit to permanent no-till everywhere. I’m glad we’ve moved on from the early no-till days when it was considered that all tilling was always bad, but practical advice was lacking.

The book includes some hard-to-find topics, such as acquiring capital, designing and setting out drainage and irrigation systems for both drip and sprinklers, and integrating livestock in a vegetable farm. Minor grumble: the index seems a little light. Fortunately, the book, like Frith Farm, is well-organized, and topics are easy to find.

Daniel started Frith Farm in Scarborough, Maine, in 2010, in his mid-twenties, borrowing $180,000 at 3.8% interest and buying a property with five open acres and a crumbling house and barn.  He had “eighteen years of expensive education and an embarrassing lack of hard skills.” His first year, he provided for a 40-member CSA from less than one acre. The farm now supplies a 150-member CSA, four natural food stores, a farmers’ market and a farm stand. They sell about $300,000 worth of food, using 2.5 acres in cultivation and 2.5 acres of pasture. Almost all of the work is done by hand, by a crew working  a 45-hour-week for 8 months, then having four months off.

Daniel recommends consistent bed dimensions, even if compromising the land geometry. He has 16 plots of 12 beds, each 100ft long, on 5ft centers. This bed-width increases the amount of growing space compared to 30ins beds. He’s over 6ft tall, so jumping over a bed is no problem. I don’t know about the rest of the crew. There are driveable surfaces between the plots and wood chip paths between beds. Without tilling, you minimize erosion, and the conventional wisdom of keeping rows across the slope, not up and down it, isn’t so vital.

Daniel recommends soil testing and an initial supply of inputs to jump start your soil health and enable you to earn a living. You’ll probably be buying compost your first year: 54 cubic yards ($25-$50/cubic yard) will provide 3ins cover on 6,000 sq ft (one Frith Farm plot). Once biological soil health is established, few imported soil amendments will be needed. You will need lots of mulch every year, such as leaves, straw, woodchips. Frith Farm uses 130 cubic yards of leaves per acre each year.

To go from a grass field to a set of ready-to-plant beds, some no-till growers do one initial tilling and maybe subsoiling to establish beds (rent or borrow the equipment). Daniel says “Don’t let purism keep you from actually breaking ground – it is better to start farming imperfectly than never to start at all!” Frith Farm tills with a Berta rotary plow on their BCS walking tractor, one 10ins strip at a time. We use a Berta plow to remake paths in our raised beds – it is a wonderful tool for that.

A second method of killing grasses and weeds is to mow closely and smother the plants with tarps. This takes 3-52 weeks, depending on the weather and plant species. This works for beds you plan to bring into production next year. Use a 5-6 mil thick black and white silage trap, black side up. Weight and wait! Daniel’s ingenious “tarp kit” consists of a pallet with enough cinder blocks to hold down a 24×100 ft tarp, which is folded and set up on top of the blocks, safely out of the way of tractor forks. The kit is moved to the next site, then returned to the pallet when its work is done. I’ve been interested in trying tarping, but muscling huge sheets of silage tarp and enough weights to hold it down was quite off-putting. Here’s an answer!

When you and the dead plants are ready, remove the tarp, spread compost thickly and plant. If the soil is compacted, use a broadfork before spreading compost. Tarping is also a valuable method for flipping beds between one crop and the next.

A third method of establishing new beds is to mow, amend the soil, cover the whole area with thick mulch, topped with compost and plant into that. To succeed, use an initial layer that lets no light through.  This method involves lots of work and mulch.

Seedling production is major at Frith Farm, as transplanting fits well with no-till. They recommend 500 sq ft of greenhouse space per acre of field production. They have some very practical “benches” which are sawhorses topped by custom pallets holding 12 standard 1020 flats. Two people can carry a full pallet, saving lots of time transferring one flat at a time.

Frith Farm uses soil blocks, mixing in a cement mixer. Winstrip trays are much quicker than making blocks, but they prefer the smaller cost and space saving of soil blocks. They use four sizes of standup blockers, but not the ¾” miniblocks, because those dry out too fast. They have tried the paperpot planter and found it unsuccessful when planting into stubble, worth considering before spending $3000.

One key to successful transplanting is appreciating the sublime experience of setting a plant in the ground with your own hands. Another is to have enough hands to get the job done! A third is watering soon after planting. They use a rolling Infinite Dibbler, a homemade oil-drum dibbler and a special 6-plant garlic dibbler For direct seeding, Daniel likes the humble Earthway seeder, even using it for cover crop seeds (the beet plate for the grasses). The Earthway is rugged, affordable, and works well in no-till beds.

Irrigation is another aspect of vegetable production that Daniel has well figured out. Here is a good clear explanation about well depth, flow, recharge rates, costs, water quality and all the facts you never needed to know if you use city water. The book includes a very clear pipe layout superimposed on the bed plan.

Daniel will help you decide between drip irrigation and sprinklers (or some of each). He recommends Senninger Xcel Wobblers with a 1gpm flow each, covering 6 beds with a line of 4 sprinklers. They run 12 sprinklers at once. This kind of detailed step-by-step calculation can be hard to find. Here’s another instance where the book pays for itself with just one piece of information! Daniel uses driptape only for long-season crops that are prone to foliar diseases, otherwise, he likes the simplicity of sprinklers. Follow Daniel’s advice and bury all main and lateral pipelines deep enough not to hit them when digging. A hose reel cart is a helpful thing to have to make hand-watering less of a tangled mess.

Daniel avoids rowcover unless a crop has two reasons simultaneously. Pests and diseases indicate imbalance, underlying issues with soil health, crop rotation, biodiversity. Work to rebalance and make improvements. Work towards being a No-Spray farm as well as No-Till.

The chapter on weeds opens with the saying “We till because we have weeds because we till . . .!” Weeds are an ecological mechanism for keeping the soil covered and full of roots. The “simple” solution of never letting weeds seed is less work in the long run, more work at first. It relies on working only the amount of land you have enough skilled hands to deal with. Two skilled fulltime workers per acre.

When is thick mulch not helpful? In early spring when you want to warm the soil. At Frith Farm, the soil is frozen from November to late March. Beds that finish too late to plant an overwinter cover crop get composted and covered in leaf mulch. They rake this leaf mulch off the beds into the paths in early spring, and spread a layer of compost on the beds, allowing some warm-up time. The dark compost absorbs the heat from the sun.

“Flipping the bed” after a crop may be simple if it was a root crop with few weeds. If the crop leaves a lot of bulky residues, mowing and tarping can restore the soil to a usable state in 5-10 days in warm weather. You may need to dig out perennial weeds, or add soil amendments, and another 7 barrows of compost per 100ft bed (2.5 cu yards/1000 sq ft), but soon you are good to go. They have a smooth compost spreading operation. A tractor driver delivers buckets of compost directly into wheelbarrows lined up at the head of the beds. People push the barrows down the paths, dumping out several shots of compost, raking the compost out to cover the whole bed surface.

Solarization with clear plastic during warm sunny weather is another way to kill weeds. If the edges of the plastic are buried, weed seeds and pathogenic fungal spores are also killed. If you want to kill weeds or crop residues without all the other life forms in the top layers of soil, using black plastic tarps is a safer way to go. The soil temperature does not get as high, but the removal of light does help kill plants. The book has a graph of days of tarping versus temperature. More than 25 days at an ambient temperature of 50F, about 9 at 65F, and only one day above 85F.

They have an ingenious foot-powered crimping tool for killing tall cover crops instead of mowing. Called the “T-post stomper”, this is a partner dance with one person at each end of a T-post lying across the bed. The T-post is tied with twine to the “inner” foot of each partner and includes a long twine loop that is hand-held.

No-till cover crop planning takes care. Plants die in three ways: they finish their lifecycle, they winterkill or they are starved of light or water. In no-till farming, the tools are the mower, winter, and tarping, or some combination of these. A sequence of photos shows beds from seeding the cover crop in September to healthy summer brassicas with no weeds in sight. A spring cover crop sequence shows peas and oats sown in April, tarped in June, direct seeded in storage radish in summer. Shorter sections on summer and fall cover crops follow.

Daniel has a chapter on integrating livestock with vegetable farming to increase diversity and net productivity of the farm. The symbiosis between soil, plants, animals can lead to creation of more soil, and increased fertility. Chickens are easy to keep, although if you want poultry that don’t scratch up the soil, get turkeys. (Daniel has a punny photo of turkey on rye.) Sheep are easier to fence than goats, and are smaller than cattle. Be wary of pigs. They can act like obsessed tillers and do lots of damage.

Harvested crops remove nutrients from the farm soil, and these nutrients can be replaced by farming for a very healthy soil biology. Healthy soil draws carbon and nitrogen from the air, and makes previously “inaccessible” stores of nutrients available to the following crops. Use compost, leaves and other organic mulches until you max out the recommended level of some nutrient. If your soil is then unbalanced, you will need to bring in missing nutrients.

The chapter on harvest sets out efficient user-friendly methods at Frith Farm. For a pleasant wash-pack space, you need a roof, a floor with good drainage (could be wood chips), mesh or slatted tables; hoses and sprayers; tanks to hold water; a salad spinner, a barrel root washer; good scales; flip-lid storage totes; walk-in coolers using CoolBot technology; and customized shelving. Think before buying a delivery truck – $1,500 worth of produce will fit in the back of a Prius! Almost no fuel costs! Daniel also recommends buying an insulated truck body to convert into a cooler. It can double as a screen for crew outdoor movie nights! Don’t forget to have fun!

We have a captive market at Twin Oaks (more politely called direct supply), so I‘m not the best reviewer of information about selling. But the section on their hiring process really grabbed me. “We are not just hiring a pair of hands to meet our labor needs; we are inviting someone into our community, our family, and our home.” Spell out and keep to high standards, provide a social experience, show care and camaraderie, train adequately, and compensate fairly. Interview well, check references, have a working interview (paid) if you can; write out your job offer. Provide guidelines with goals for pace and efficiency. Each person should be able to harvest, wash and pack about $80 worth of produce per hour. Share the joyful observations of life around you.

Daniel describes his recordkeeping, where the plan becomes the record. He recommends Holistic Management by Allan Savory with Jody Butterfield. Define your farms’ purpose, plan the season, plan the week. A plan is just a plan, sometimes plans change. Look for opportunities to record aggregate data, such as recording what you take to market and what you bring back, rather than each individual sale. At the end of the season, add up sales for each crop and divide by the number of beds to calculate the revenue per bed, and the yield of that crop. Having standard sized beds makes this simple. Add into pre-existing records and eliminate multiple versions of the same data. Make one spreadsheet of notes for next year. You can sort it by crop or by month, or by plot number.

Their Plan for the Week is an online spreadsheet accessible to all via a laptop in the barn. (Obviously they have better internet than we do!) Each week has a tab, each day has a column, and each plot has a row with tasks, times and sometimes a name. Once a week, the crew walks the farm and makes the list for each day, including any tasks carried over. Nothing is erased (it becomes a record!) When someone completes a task, they use a strike-through font and add notes. At the end of each day, remaining tasks are reprioritized for the rest of the week. This spreadsheet becomes the farm journal, and is easily searchable.

Frith Farm has a four-year rotation starting with smothering followed by transplanted cucurbits or nightshades and a winter-killed cover crop. The second year involves brassicas followed by root crops, with mulch over-winter. The third year is devoted to repetitions of salad crops, and a winterkilled cover crop. The fourth year is for alliums and an over-wintering cover crop. Consider the crop spacing you need for the new crop, and the spacing of the stubble from the previous crop. You often don’t need a clear bed, just clear rows where you intend to plant.

During the winter they create their attractive crop rotation plan where each plot has 12 rows (for the beds), with “under-rows” (for under-sowing) and 12 columns (for the months). It’s color coded for quick reference. From that rotation plan, they create a Greenhouse Plan and a Seed Order.

Next is a Harvest Plan for each harvest day, starting with walking the fields to take notes, balancing what is mature with what is needed. The evening before, the harvest manager makes a list of crops, quantities, and picking order. Each harvest day has a tab on the online spreadsheet, with a row for each crop. The sheet for that day is posted by the time the crew arrives. In this case, pickers use a pen to indicate who is picking what, when it’s done. People work down the list in order, taking the crops to the wash-pack station. That crew cleans the produce and stores it in a cooler, labeled with its destination.

There is a table of revenue data for 16 top-earning vegetables. (The other 45 crops are not shown.) In terms of revenue per bed, ginger wins at $2442, but it is in place all year (and I think it is in high tunnels). Taking bed-months into account, ginger still wins, but arugula is chasing it. Radishes don’t so well in revenue per bed-season, nor do onions and beets. Frith Farm does not record labor per crop. CSA growers need to provide variety, not just the “most profitable” crops.

Success includes sustainability, considering the people and the planet as well as the profit. Profit can be understood as ability to reinvest. Exactly where the profits end up is important, and to his credit, Daniel includes his 2018 farm revenue and where it went. Of the total $314,000, $120,000 went to the farm crew (an investment in the local community that makes the farm productive); $11,000 to family loan payments. $92,000 went back to the land (infrastructure, seeds and local biomass). $91,000 left the area, for taxes, insurance, fees, tools and equipment, and non-local inputs including the energy bill.

Purchases like plastic mulch, fossil fuels and manufactured equipment are part of a linear process that essentially convert resources to pollution. Strong words, and why not? We need to each face the full effect of our production.

Frith Farm works to increase food access to people in the community who cannot afford the usual prices of healthy food. They accept SNAP and WIC, donations, and offer gleaning groups the chance to help food pantries. They have sliding scale pricing, barter, work trades, and ride shares, all of which they advertise widely.

On the ecological front, their no-till practices are working daily to increase carbon sequestration by increasing organic matter (less than 4% in 2011, over 10% in 2019). A one per cent increase in OM in the top 10” of an acre of soil removes about 8.5 tons of carbon from the atmosphere.

Daniel Mays
Photo Storey Publishers

Root Crops in December

Root Crops to Plant in Central Virginia in December

A stormy winter day, garlic, rowcovered spinach beds and our hoophouse.
Photo Wren Vile

Reread Root Crops in October for more ideas of things you might plant, if you are in a much warmer climate zone than us. We are in winter-hardiness subzone Zone 7a, with an average minimum temperature of 0° to 5° F (-18°C to -15°C). We’re not planting anything outdoors in central Virginia in December. But in the hoophouse, we are sowing a couple of things.

Eliot Coleman has given the name Persephone Days to those with less than 10 hours of daylight, when little plant growth happens. Here in central Virginia, the Persephone Days last from November 21 to January 21.  Further north, the period is longer, and it is necessary to grow more of what you want to eat in winter and keep it in a holding pattern to see you through to the other side of the Persephone Days. The holding pattern could be crops in storage, which I wrote about in Root Crops to Plant in Central Virginia in November. Or it could be crops in the ground in a hoophouse.

Temperature also contributes to rate of growth and this is where hoophouse crops score big! It can be a lot warmer during sunny days inside a hoophouse, and our double-plastic hoophouse keeps nighttime temperatures about 8F (4.5C) degrees warmer than outdoors, sometimes 10F (5.5C) degrees warmer. In addition, plants can tolerate lower temperatures inside a hoophouse. The soil stays warmer and the plants recover in the warmer daytime conditions (it seems to be the night+day average temperature that counts). We find, in practice, the period of slowest growth here is December 15 to February 15: still two months long, but lagging the shortest days by three weeks. It takes time for the soil to cool down in late fall and time for it to warm up in early spring.

Hoophouse radishes and Yukina Savoy in December.
Photo Wren Vile

In our double-layer hoophouse, plants without any inner rowcover can survive 14F (7.7C) degrees colder than they could survive outside; with thick rowcover (1.25oz Typar/Xavan) inner covers, at least 21F (11.6C) degrees colder than outside. For example, salad greens in our hoophouse can survive nights with outdoor lows of 14°F (-10°C). Turnips (and many cooking greens) survived a hoophouse temperature of 10.4°F (-12°C) without rowcover, -2.2°F (-19°C) with.

In early December, we sow turnips #3. We sow Hakurei, Early White Egg, Oasis, and Red Round. They will struggle a bit to grow, so they are only worth sowing if we thin them promptly and harvest them on the small size, as the plants will start bolting in early March. See Root Crops in October, for details of thinning and harvesting.

In late December, we sow hoophouse radishes #5, Easter Egg and White Icicle. Cherry Belle and Sparkler types grow too fibrous at this time of year. See Root Crops in September for more about our succession of hoophouse radish sowing dates. Unlike the late October sowing which lasts for 8 weeks, the November sowing will only be good for the (slow-growing) four weeks of February, and this late December one for four weeks from mid-February to mid-March. In this case, it is because the temperature in the hoophouse and the daylength will have increased by then and the radishes will grow fast and start bolting.

Young Red Round turnips in our hoophouse in late November.
Photo Pam Dawling

Root Crops to Harvest in Central Virginia in December

In central Virginia, there are normally no roots that we could be harvesting outdoors in December except parsnips. Jerusalem artichokes are hardy down to 0°F (-18°C), but we haven’t grown those in decades. Horseradish is similarly hardy, but not a mainstay of nutrition. The months with R in them are the horseradish harvest months. This is not woo-woo, it happens that September to April have R in them, and the summer months do not!

Horseradish regrowing up through the mulch in early spring.
Photo Kathryn Simmons

If temperatures have not yet dropped to 12°F/-11°C, we could dig Danvers carrots, Cylindra beets, and any rowcovered rutabagas (swedes). Albina Verduna, and Lutz Winterkeeper beets are hardy down to 15°F (-9.5°C), as are most kohlrabi and rowcovered turnips. But we don’t take that chance. We like to gather our root crops in and have them safely stored. We also like to put our feet up more in December!

Covered beets, covered winter radish are OK down to 10°F (-12°C).

In the hoophouse we can harvest radishes #2 until 12/25, #3 (sown October 30) from 12/15 to 2/1. We harvest our first turnips (sown around October 13) as thinnings from November 29 and by pulling out the biggest from December 5, until mid-February, by which time we can have made a start on the second sowing (October 25).

Turnips in our hoophouse in December.
Photo Wren Vile

See my list of Winter-Kill Temperatures of Cold-Hardy Winter Vegetables 2020 for a more complete picture of “Harvesting in Time”

Other Root Crop Tasks in Central Virginia in December

From storage we can eat (if we grew them!) beets, carrots, celeriac, kohlrabi, parsnips, potatoes, rutabagas, sweet potatoes, turnips. Stored crops need to be visited at least once a month and checked for decay.

In our winter squash cage we keep some pancake turners rejected by the kitchen crew. If a squash is having a meltdown, I slide it onto a tray or a bucket lid and throw it outside. The first time I did that this year, I made the mistake of sliding a second squash on top of the first on my bucket lid. The first one couldn’t support the weight of the second. Messy! Sliding them into a bucket would have been safer.

A fine winter squash medley (no, they’re not root crops!)
Photo Southern Exposure Seed Exchange

Special Root Crop Topic for December in Central Virginia

Crop Review and Planning Part One

This is a wider task, not restricted to root crops. In November we have a Crop Review, and then start to plan our crops for next year. We like to get our seed orders in early, to maximize our chances of getting the varieties and quantities we’d like. Some seeds might be in short supply this time, because of all the new gardeners and Covidsteaders that joined our ranks this year.

We consider how well our crops did in terms of plant vigor, disease-resistance, yield, quality, flavor and timing. Did they come in all at once? A benefit for storage crops or those you might sell wholesale. Not so great if you want an extended harvest period.

Planting dates, soil quality, sufficiency (or otherwise) of pest and weed control, plant protection from the elements are all factors that affect yield and crop quality. We can plan to make changes to those things next year. We can decide to plant a different amount, or spread out the planting dates. This can lead to a new calculation of how much seed to buy for the coming year.

By now the seed catalogs are starting to arrive and we can look at what varieties are on offer. Is there a faster-growing turnip? A different carrot we’d like to try? Something with more resistance to the disease we noticed this past year? Something more recommended for our climate or region? While you’re browsing, make a back-up plan if you can’t get your first choice, either from the same catalog, or another.

Hoophouse turnips and baby lettuce mix in December (note the low sun angles!)
Photo Wren Vile

New and Upcoming Online Events 2020-2021

I’m making this extra mid-week post because I haven’t offered many events this year, and you may have stopped looking on my Events Page!

Click here Make the most of the offseason by getting a step up on planning next year’s garden with this informative and enlightening course from author and Fair speaker Pam Dawling. Workshops include setting your garden goals (how to plan and which crops to grow), mapping, crop rotations, growing transplants, scheduling seedlings, interplanting, contingency plans, and so much more! (Note: If you’ve registered for the All-Access bundle, you now have access to this course!)

Mother Earth News Fair Online

My new contribution to the Mother Earth Fair Online has just arrived – a Garden Planning Course of eight workshops, with handouts, and a resource list.

Workshops include setting your garden goals (how to plan and which crops to grow), mapping, crop rotations, figuring out how much to grow of what, growing transplants, scheduling seedlings, interplanting, contingency plans, and so much more!

Click here to read more and sign up. You can get my Garden Planning course for $20 or the 2021 All-Access Package at $2.99/month or $35/year – the complete collection of online courses (currently 39) and recorded webinars – with more than a dozen new courses in the works! Each online course includes 6-8 video workshops of about 30 minutes each and supporting materials (called “handouts” in the days of physical in-person events).

I also have a workshop on Winter Cover Crops in the Winter Gardening course. There is a link to that course just below my photo on the page I linked to.

This can give you an inspiring way to invest some time this winter. We know lots of new gardens were started in 2020, and maybe you are dreaming of a bigger and/or better garden in 2021. Turn your dreams into plans and get off to a smooth start! 

This big Online Fair also makes a nice gift! (Scroll to the end of the View All Courses second page, for the All-Access Gift icon, 39 courses for $75. It includes a half-price offer on all courses that will be added during 2021.

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Organic Growers School 28th Annual Spring Conference

Online, March 13-21, 2021

The Organic Growers School Spring Conference 2021 is all virtual this time! Attendees will learn how to farm, garden and live organically through 12 tracks and more than 30 workshops.   You won’t have to choose between two or more great workshops that are on at the same time. This year you’ll be able to “attend” every one. In your pajamas if you want.

Kick-off Live Event on March 13, 2021  

  • Three live Keynote Talks
  • Teaser videos for our 12 Themed Tracks
  • Lunchtime Entertainment
  • A live Q&A with our Keynote speakers
  • A video social with other attendees
  • Access to our Exhibit Hall

March 14-19, 2021 – Themed Track Workshops

View 3 pre-recorded hour-long workshops in each of 12 Themed Tracks:

    • Keynote
    • Cherokee Foods
    • Cooking
    • Farming
    • Food Systems
    • Gardening
    • Herbs
    • Livestock
    • Mushrooms
    • Permaculture
    • Soils
    • Sustainable Living

March 20-21, 2021 – Live Track Closing Panel Discussion Sessions

  • Join a live Panel Discussion with each speaker from the Track workshops
  • Interact directly with panelists during the live Q & A portion

In the Gardening Track, Ira Wallace and I will be presenting The Seed Garden. Details to come, as we iron them out.

Garden cart with supplies for watermelon seed collection.
Photo Pam Dawling

I have been slow to join in the world of online events for a few reasons.

One is that in my rural county, we have poor internet connections and slow speed. I cannot reliably participate in a video conference where I’m one of the speakers. The service could just drop my connection at any time. This is a reality of many parts of rural America. We need something like the Rural Electrification Act to bring us into the 21st century. 2017 marked the 80th anniversary of that piece of Roosevelt’s New Deal.

A second reason is that I live as a member of Twin Oaks, an intentional community, where we share values of cooperation, sharing, nonviolence, equality, and ecology. We also share our resources. That includes our bandwidth. We have chosen not to spend a lot of our income on funding fast internet (it could be a deep black hole).

A third reason is that we have chosen to stay home as much as possible, to reduce the risk of Covid-19 infection in our large household. Our group includes people who are more

vulnerable, due to age or health. We chose to self-quarantine, and think of ourselves as in a big bubble. It’s wonderful not to need masks or distancing at home. Anyone who goes off the farm has to be careful about masking and distancing, and about sanitizing on return, even quarantining alone for two weeks if the risk seems high. Going into a city to do video-conferencing is just not something I’m willing to do!

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Articles in Growing for Market

I’ve started a new run of writing articles in Growing for Market, a magazine. Upcoming is an article about collards. In recent months I’ve written about both wet and dry seed processing, planning garlic planting, and methods of growing sweet potato slips.

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Articles in Mother Earth News

I have an article coming up in the Mother Earth News magazine, about making and using open wood flats for seedlings and transplants. I also contribute to their blog, in the Organic Gardening section.

Winter hoophouse growing

 

Hoophouse Yukina savoy at the end of November.
Photo Ethan Hirsh

Last week I wrote about Winter Preparations for Vegetable Gardens. For those with a hoophouse, here are some notes on all the work we can do to grow winter crops there! For those without a hoophouse as yet, scroll to the end for Twenty Benefits of Having a Hoophouse

First, a roundup of previous blogposts on winter hoophouse topics.

Planning winter hoophouse crops includes a description of how we do our hoophouse crop planning so we can maintain a crop rotation and still pack the beds fully with hardy crops.

Fall hoophouse bed prep and shadecloth removal includes spreading compost, broadforking, and a step-by-step guide to hoophouse fall bed prep.

Hoophouse fall bed prep Plans A-D and spider-webs includes some lovely spider photos and a short video of ballooning, as well as info about our first-planted winter crops.

Hoophouse bed broadforked to loosen up slumped soil. I’m happy to say our soil structure has improved in the 18 years since this photo was taken!
Photo Pam Dawling

Young greens in the hoophouse

After the set-backs with our winter hoophouse greens transplants that I wrote about in Hoophouse fall bed prep Plans A-D and spider-webs, we worked really hard and got the whole house planted up. Most of the transplants have recovered from their transplant shock (wilting each day), during the cloudy weather we had.

The new seedlings are coming up fast and calling on us to thin them. We ended up not needing so many of the Plan D plug flat plants, but we’ve kept them for now “in case” .

Plan D: Winstrip seed flats in our hoophouse on Oct 16, a late attempt to catch up!
Photo Pam Dawling

Ultimately if we don’t need them, they’ll go in a salad mix. I wrote about Making baby salad mix last year. The past two days I have been able to harvest a mix in the hoophouse. The ingredient we are shortest of is lettuce. My first mix was spinach, Bulls Blood beet leaves, a few leaves of Tokyo Bekana, Bright Lights chard, Scarlet Frills, Ruby Streaks and Golden Frills, and a handful of lettuce leaves Red Tinged Winter is growing fastest, of all the varieties we planted this year.

Sowing hoophouse winter crops includes some discussion of the tools we like; pre-sprouting spinach seed and growing multi-leaf lettuce.

What’s growing in the hoophouse; reading; planning for winter is an October view of crops.

Frilly Mustards in our Winter Hoophouse is exactly what it sounds like. Four sowings, six varieties. All delicious.

Making baby salad mix includes a discussion of ingredients and methods, balancing nutrition, color, shape and loft.

Young green Panisse and red Revolution lettuce in our hoophouse in November.
Photo Pam Dawling

Cold-tolerant lettuce and the rest, our January 2018 assessment of the varieties we grew that winter and which survived the unusually cold spell we had. Includes sad photos of the casualties!

Also see my Mother Earth News blogpost from August 2018 Grow Great Lettuce in Winter

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Hoophouse seedlings growing outdoors under insect netting. Starting transplants outdoors helps the rotation by reducing the time the crop is growing in the hoophouse
Photo Pam Dawling

Do you value crop rotation in your hoophouse?

In the winter 2019-2020, a reader in the Pacific Northwest wrote: “This winter I have been re-thinking my crop rotation plan after having some issues (with flea beetle larvae in the soil outsmarting my diligent insect netting of my brassica salad crops). These days I see intensive market gardeners seeming to not worry so much about rotation (i.e. Neversink farm, etc), and yet I’ve always been taught that it is such an important principle to follow. I reviewed your slideshows on crop rotation and also cool crop planning in the greenhouse (which briefly addresses salad brassica rotation with other crops). With how much space I have and the high demand I have for brassicas, for salad mix (mustards) and also the more mainstay cole crops, I had settled on a 2.5 yr between brassica crop rotation (but planting two successions of mustards in the same bed within one year, in the year the bed was in mustards, with a lettuce or other crop breaking up the successions, with the idea that they were very short day and also light feeder crops). Wondering if you think this just doesn’t sound cautious enough, or if this sounds like a reasonable compromise with not having more space to work with (and wanting to satisfy the market demand for brassicas).”

I replied: “Yes, I do think crop rotation is important. I do know some farms seem to have given it up. I think what you are seeing shows one reason why rotation is important. In our hoophouse, we do as you do, allocating brassicas to a space for that winter season and perhaps doing more than one round of brassica crops. Then moving away from brassicas for the next two winters. If doing that doesn’t get rid of the flea beetle problem, and you are being thorough about netting with small-enough mesh netting (sounds like you are, but maybe check the mesh size), then my next step would be spinosad when the flea beetles appear. You can spray the inside of the netting too, and close it quickly. It’s that or a longer rotation, which it sounds like is not financially viable. You could also try farmscaping and/or importing predatory insects (not sure if there are any), Are there beneficial nematodes that attack flea beetle larvae? These are things I don’t know about, but might be worth looking into.”


Doing a spot of research today, I find that Heterorhabditis bacteriaphora, (Hb nematodes) a beneficial nematode fromArbico Organics will attack flea beetles. also known as NemaSeek, and sold separately. This is the wrong time of year for introducing nematodes in most of the US. They need warm weather to thrive.

Another suggestion from Arbico is BotaniGard Maxx & other B. bassiana sprays, which infect and kill adult flea beetles. Repeat applications as needed throughout the growing season.

Kaolin clay (Surround) is another possibility.

Also see Harvest to Table on the topic of dealing with flea beetles

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View through the hoophouse doors in December.
Photo Kathleen Slattery

Add a hoophouse to your food production

For those of you wistfully thinking about a hoophouse, let me help you a step closer to having one next year! Sales of my Year-Round Hoophouse book are doing well, which suggests to me that quite a few gardeners and growers are thinking in this direction.

Twenty Benefits of Having a Hoophouse

  1. An extended growing season because plants are protected from cold weather.
  2. Faster growth and higher total yields.
  3. Beautiful unblemished crops not battered by the elements.
  4. Fewer foliar diseases because the leaves can stay dry.
  5. Crop survival at lower temperatures in the hoophouse than is possible outdoors.
  6. Better crop recovery in winter due to warm sunny days following the cold nights.
  7. Some protection from deer and other pests large and small.
  8. Soil temperature stays above 50F (10C) in zone 6b. Warm soil = faster cold weather growth.
  9. Higher proportion of usable crops – more food, higher sales dollars.
  10. Diverse crop portfolio – grow crops that wouldn’t succeed outdoors in your climate.
  11. Harvest whenever you need the crops, even during pouring rain!
  12. Wonderful working conditions – no need for gloves and hats; take off your coat.
  13. A food garden on a manageable scale.
  14. A place to enjoy practicing intensive food production.
  15. The chance to have an area completely free of weeds – new weed seed doesn’t blow in.
  16. No need to work with heavy machinery.
  17. Much better value for producing crops (per dollar invested) than a heated greenhouse.
  18. Can be constructed by generally-handy people. Specialists are not needed.
  19. NRCS grants are available for some hoophouses. Natural Resources Conservation Service, Environmental Quality Incentives Program, High Tunnel System Initiative.
  20. Ecological energy use. The embodied energy of the plastic is less than the energy that would be used to ship similar produce from somewhere warmer (Eliot Coleman, Four Season Harvest). Another study found this was not true for smaller (9 x 12 m) hoophouses – although the economic incentive for growers is still true, there is no energy efficiency advantage to the planet. Smaller carbon footprint: shipping 1 kg lettuce has 4.3 times the CO2 footprint of locally grown hoophouse lettuce. Plawecki, R., Pirog, R., Montri, A., & Hamm, M. (2014). Comparative carbon footprint assessment of winter lettuce production in two climatic zones for Midwestern market. Renewable Agriculture and Food Systems, 29(4), 310-318. doi:10.1017/S1742170513000161.
September sown White Russian kale (transplanted in October).
Photo Wren Vile

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Know your climate

WeatherSpark climate summary for Louisa, Virginia. Go to the website to click for more information

The WeatherSpark website provides “The Typical Weather Anywhere on Earth”. Enter your nearest town or airport and you get clearly explained info with fascinating graphics of how the weather goes over the year in your locality. Note this is not a forecast site, it’s about average weather for each place. Useful to people who’ve recently moved and want to know what to expect this winter, or to new gardeners who haven’t paid so much attention previously. Or to those who want to check their assumptions (I really thought the wind was out of the west more of the time than records say). There are charts of high and low temperature, temperature by the hour each month, cloud cover, daily chance of precipitation (both rainfall and snowfall), hours of daylight, humidity, wind speed and direction and solar energy. A big help in making wise decisions. I know that climate change is going to cause havoc with averages, and we’ll need to learn to become better weather forecasters individually, and to use soil temperature and other metrics to decide when to plant. This website explains things well.

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Winter gives a time for most of us to ponder success, failure, and possibilities for doing things differently.

 

Winter Preparations for Vegetable Gardens

 

Frosty daikon radish
Photo by Bridget Aleshire

Winter-Kill Temperatures

My annual blogpost of Winter-Kill Temperatures for Cold-Hardy Vegetables is always very popular. In fact, it’s my most popular title! Usually searches for this info increase in October and peak in early November, so here are quick links for those of you who have been meaning to look something up.

Winter-Kill Temperatures of Cold-Hardy Vegetables 2020

Winter Kill Temperatures of Cold-Hardy Vegetables 2019

Winter-Kill Temperatures of Cold-Hardy Vegetables 2018

Winter Kill Temperatures of Winter-Hardy Vegetables 2016

Trimming roots from a leek in December.
Photo Pam Dawling

For several years, starting in 2012, my friend and neighboring grower Ken Bezilla of Southern Exposure Seed Exchange and I have been keeping records of how well our crops do in the colder season. Ken provided much of the original information, and has suggested the morbidly named Death Bed idea: set aside a small bed and plant a few of each plant in it to audition for winter hardiness. Note each increasingly cold minimum temperature and when the various crops die of cold, to fine-tune your planting for next year (and leave me a comment!) Each year I update the list, based on new things I learned during the recent winter.

We are in zone 7a, with an average annual minimum temperature of 0-5°F (-18°C to -15°C).

The winter 2019-2020 was mild, with our lowest temperature being a single night at 12°F (-11°C). The Koji greens became completely unmarketable but did not completely die. Yukina Savoy is indeed hardier (as I expected), being OK down to 10°F (-12°C). We had one night at 13°F (-10°C) and two each at 17°F (-8°C), 18°F (-8°C also) and 19°F (-7°C). That winter I noted the death of rhubarb stems and leaves at 25°F (-4°C), rather than 22°F (-6°C), as I noted a year or two ago. I also added some cover crop hardiness temperatures.

Rhubarb in spring.
Photo Kathryn Simmons

I also learned that there is more damage when the weather switches suddenly from warm to cold. And that the weatherman in Raleigh, NC says it needs 3 hours at the critical temperature to do damage. Also note that repeated cold temperatures can kill off crops that can survive a single dip to a low temperature, and that cold winds, or cold wet weather can destroy plants quicker than simple cold. All greens do a lot better with row cover to protect them against cold drying winds.

Winter hoophouse lettuce
Photo Kathryn Simmons

It’s worth noting that in a double-layer hoophouse (8F/5C warmer at night than outside) plants can survive 14F/8C colder than they can outside, without extra rowcover; at least 21F/12C colder than outside with thick rowcover

Salad greens in a hoophouse in zone 7 can survive nights with outdoor lows of 14°F (-10°C). A test year: Lettuce, Mizuna, Turnips, Russian kales, Senposai, Tyee spinach, Tatsoi, Yukina Savoy survived a hoophouse temperature of 10.4°F (-12°C) without rowcover, -2.2°F (-19°C) with. Bright Lights chard got frozen leaf stems.

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Seeking Reader Participation

Your experience with your soils, microclimates and rain levels may lead you to use different temperatures. I’d love to hear from readers if they’ve found my numbers work for them, or if they have a different experience. You can leave a comment here, and it will appear on the website, for others to consider. Or you can fill out a Comment Page and only I will see it, although I’ll pass on the information without your name, if I think others would like to know too.

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Preparing for winter

Rowcover rolling with crank handle.
Photo Rodaew Institute

I’ve also written posts about winter preparations

Getting ready for frost. This post includes info on DIY weather-forecasting, our Frost Prediction checklist, and our Frost Alert Card. Also a link to a 126 page book which includes explanations of freezes and frosts to help us make sense of advice we’ve not understood. FrostProtectionFundamentalsPracticeandEconomicsFAO.pdf

Preparing for Frost and Cold Weather. This post includes our Frost Alert Card, a Frost Predictions checklist of what to do when the first fall frost is expected; how to use sprinklers overnight to stop tomatoes from freezing; four ranges of cold-hardiness (some crops can wait in the garden till it gets colder); and different levels of crop protection, including rowcover, low tunnels, Quick Hoops, caterpillar tunnels and hoophouses (aka high tunnels).

Season Extension and Frost Preparations. This post includes my Season Extension slideshow; the Frost Alert Card and Frost Predictions checklist again; a diagram of our winter double hoop system to hold rowcover in place during the worst weather;

Double hoop system for winter rowcover.
Pam Dawling

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Changing Winter Temperatures

Here’s an article from the Virginia Mercury by Sarah Vogelsong, giving info about changing winter temperatures, particularly later fall frosts in Virginia:

The frozen Potomac River. (Sarah Vogelsong/Virginia Mercury)

Autumn’s first frost is falling later. For farmers, the consequences are wide-ranging

by Sarah Vogelsong, November 3, 2020

Halloween has come and gone. The clocks have been set back. Every evening darkness falls just a little bit earlier.

But for much of Virginia, the first frost still remains elusive.

Over the past century, the average date of the first frost has been moving progressively backward throughout the commonwealth, today landing a week or more later than it did at the turn of the 20th century.

“This is one of the clearest signs of not only the changing climate but … its impact on our systems,” said Jeremy Hoffman, who as chief scientist at the Science Museum of Virginia conducts extensive research on climate change in Virginia. “It’s not just here, it’s everywhere.”

As global temperatures have warmed, largely due to the release of greenhouse gases into the atmosphere, frost seasons have shrunk. The Fourth National Climate Assessment released by the Trump administration in 2018 reported that “the length of the frost-free season, from the last freeze in spring to the first freeze of autumn, has increased for all regions since the early 1900s.”

How the shifts have played out in different states with different geographic, ecological and topographic features varies. Data from the U.S. Environmental Protection Agency show that between 1895 and 2016, the average date of the first fall frost moved back by 7.1 days in Virginia.

On the local level, the changes may be even starker. Estimates of how much the average date has changed vary depending on the time range used and how scientists fit a line to their data points, but in most Virginia cities, they show unmistakable upward trends. Looking at first frost dates between 1970 and 2016, Climate Central, a nonprofit staffed by scientists and journalists, calculated that on average, the first frost today is 5.9 days later in Lynchburg, 8.9 days later in Harrisonburg, 12.8 days later in Roanoke, 15 days later in Charlottesville and 18.5 days later in Richmond. While their data show Norfolk’s first frost occurring about six days earlier on average, Hoffman said that longer-range data going back to 1940 show the first frost moving back by about five days. Still, he cautioned, variation does occur: “Localized things like weather” can “work against that dominant signal in datasets like these.”

First freeze dates for Richmond, 1930-2019. (Jeremy Hoffman, Science Museum of Virginia)

The implications of the shifts in the freezing season go beyond a few more days to enjoy warm weather, say scientists and policymakers. Perhaps most affected are farmers, whose livelihood is intimately tied to fluctuations in both short-term weather and long-term climate.

“Some things you can sort of manage around and some things you can’t,” said Wade Thomason, a professor of crop and soil environmental science at Virginia Tech and the state’s grain crops extension specialist.

For most farmers, the last frost of the year in the spring is the riskier of the season’s two endpoints, falling as it does when most plants are young and more vulnerable to temperature extremes. But ongoing changes in the first frost in the fall also have ripple effects.

“It can be a beneficial thing for some instances. We might get more grazing days for livestock operations in a year,” said Thomason. For some crops, like double-cropped soybeans that are planted following the harvest of another crop — typically a grain like wheat — “it can extend the season.”

Other effects are less immediately apparent. Many wheat farmers who typically plant in mid-October have begun to push back their planting dates to ensure plants don’t grow too quickly during the freezing months, making them susceptible to disease or falling over in the field. Specific types of forage rely on long periods of cool weather to thrive: in Northern Virginia and the Shenandoah Valley, farmers have noticed that orchard-grass stands are only living for four to five years instead of the once-standard 10.

“For years now, we’ve heard from farmers that the stands don’t persist like they used to,” said Thomason. Research has shown that one factor contributing to less persistence is warmer nighttime temperatures, he added, but because most operations rely on cultivars developed decades ago, “we haven’t adapted orchard grass that thrives in a warmer climate.”

Other crops affected by longer warm seasons? Tree fruits and wine grapes

“Virginia’s one of those places that we expect to get hotter and we also expect to get wetter,” said Benjamin Cook, a climate scientist with the National Aeronautics and Space Administration’s Goddard Institute for Space Studies whose research includes the effects of climate change on vineyards. Neither of those conditions are necessarily good for high-quality wine prospects, he said. Furthermore, farmers working in these areas face special risks because of the long time to maturity of their crops.

“Those are parts of the agricultural world that adaptation eventually becomes a lot more challenging, because you can’t switch crops from year to year,” he said. “You have to make a bet on something and wait four years to see if it pays off.”

Regardless of their specialty, all farmers face another consequence of shorter freeze seasons: more weeds and more pests.

“With longer growing seasons, with these warmer winters, the populations of insects are increasing, the mortality is lower, they can produce more generations a year, and that potentially presents a problem for agriculture and plants in general,” said Cook.

Those effects can be seen on the ground, said Thomason: “Maybe 30 years ago, we could stop worrying about them in early October, and now it may be a week or 10 days later.”

https://www.virginiamercury.com/ Virginia Mercury is part of States Newsroom, a network of news outlets supported by grants and a coalition of donors as a 501c(3) public charity. Virginia Mercury maintains editorial independence. Contact Editor Robert Zullo for questions: [email protected] Follow Virginia Mercury on https://facebook.com/thevirginiamercury and https://twitter.com/MercuryVirginia

Our stories may be republished online or in print under Creative Commons license CC BY-NC-ND 4.0. We ask that you edit only for style or to shorten, provide proper attribution and link to our web site.

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Root Crops in November

Root Crops to Plant in Central Virginia in November

We have reached the slow-growing time of year. We have passed our last chance to sow root crops outdoors. Nothing changes fast. Reread Root Crops in October for more ideas, if you are in a warmer climate zone than us. We are in Winter-hardiness zone 7, which has overall minimum average of temperatures of 0° to 10°F (-18°C to -12°C). We are in subzone Zone 7a, with a minimum average temperature of 0° to 5° F (-18°C to -15°C).

In late November, we sow our fourth radishes in our hoophouse. See Root Crops in September for more about our succession of hoophouse radish sowing dates. We sow Easter Egg, and White Icicle. It is too late for us to sow Cherry Belle or Sparkler types – they get too fibrous. This sowing will feed us for the month of February. Unlike the late October sowing which lasts for 8 weeks, this sowing will only be good for 4 weeks.

See Root Crops in September for information on figuring sowing dates for winter hoophouse succession crops (radishes are the example)

Late September in our hoophouse: radishes, scallions and new transplants in the beds on either side. Photo Wren Vile

In early November (around 11/9), we often sow our second of three plantings of hoophouse turnips. We sow Hakurei, Early White Egg, Oasis, and Red Round. These will be harvested 2/25-3/10 (with thinnings for greens from 1/11).

Sometimes we make our second sowing in late October, if we have space available then and want bigger turnips. We may make a third turnip sowing in very early December if space opens up then. The third sowing is only worthwhile if thinned promptly and eaten small, as the plants will start bolting in early March.

See Root Crops in October, for details of thinning and harvesting.

Root Crops to Harvest in Central Virginia in November

Large Smooth Prague celeriac.
Photo Southern Exposure Seed Exchange
Florence bulb fennel. Photo
Southern Exposure Seed Exchange

 

 

 

 

 

 

If you are unsure how soon temperatures will drop in your area, see Weatherspark

Enter your city, airport or zipcode and you’ll get access to helpful graphics on seasonal temperatures, cloud coverage, rainfall, snow, sunshine, humidity, wind, water temperature at nearby large bodies of water. Also tourism, which I had not previously thought of as a type of weather! After that comes an assessment of growing conditions (considered only as days without frost) and growing degree-days, solar energy, and more.

In Louisa County, where we are, the average daily low temperature in November makes a precipitous but erratic slide from 45°F (7°C) to 36°F (2°C), with a small chance of going as low as 24°F (-4°C) by the end of November. Most of our root crops other than sweet potatoes and potatoes can wait to be harvested until late November, but we would rather proceed with harvesting and storing, as the daylight gets shorter and the chance of cold, wet working conditions get higher.

Green kohlrabi.
Photo Small Farm Central

 

We continue clearing root crops outdoors and storing them (in this order): 

  • ·         25°F/-4°C, bulb fennel
  • ·         20°F/-7°C, turnips, winter radish, celeriac
  • ·         15°F/-9°C, kohlrabi, beets (15-20°F/-9 to -7°C, depending on variety)
  • ·         12°F/-11°C, carrots, Cylindra beets
  • ·         10°F/-12°C, parsnips, probably OK to 0°F (-18°C)
  • ·         Horseradish is not killable by cold temperatures, as far as I can tell. But if the ground is frozen, you can’t dig it up.

Wash and store roots in perforated plastic bags under refrigeration, or in a root cellar or other cold storage place.

Our 9/6 sowing of hoophouse radishes will have finished and our second sowing will mature and brighten our meals from 11/6 to 12/25 approximately. Our first sowing of hoophouse turnips (10/15) will produce edible little roots as thinnings later in the month.

See Washing, sorting and storing root crops in Root Crops in September.

See my list of Winter-Kill Temperatures of Cold-Hardy  Vegetables 2020 for a more complete picture of “Harvesting in Time”

Other Root Crop Tasks in Central Virginia in November: Long term storage of sweet potatoes and white potatoes

Sweet Potatoes in storage.
Photo Pam Dawling
Sweet potatoes

After curing, store boxes of sweet potatoes at 55-60°F (13-15.5°C), 50-60% humidity. Curing is complete when the skin is undamaged after rubbing two together. If the heating in your curing space is variable, be sure to check several boxes of sweet potatoes closer to and further from the heater. We once had a sad thing happen after a new heater had been installed. We were checking the most accessible boxes only, not the ones at the back near the heater. We got wrinkly sweet potatoes. If your crop is not curing as fast as you hoped, check the temperature, and do what you can with fans to move the air around without blasting directly on any particular box. Also check the humidity and adapt as needed. We found that splashing water directly on the concrete floor of our basement was the most successful method.

 

Restack the boxes (in a rodent-proof storage cage, if you are using an outbuilding).

Peruvian (“white”) potatoes

 

Potatoes stored in crates in our root cellar.
Photo Nina Gentle

Sort white potatoes in storage 2 weeks after harvest. See Root Crops in August

Root Cellar: Cool to 50°F (10°C) after one month, then 40°F (4.5°C), airing once a week or less if cooling not needed. See Special Topic for July

Special Root Crop Topic for November in Central Virginia Vegetable storage without electricity.

  • ·         Meeting the storage requirements of various crops helps maximize their season of availability
  • ·         Some vegetables need to cure before storage and the curing conditions are different from those needed for storage. Curing allows skins to harden and some of the starches to convert to sugars.
  • ·         Many crops may be stored without electricity, perhaps in buildings that serve other uses at the height of the growing season.

  • ·         Washington State University Extension’s Storing Vegetables and Fruits at Home, is a good introduction to alternatives to refrigerated storage, using pits, clamps and root cellars. Drawings below are from WSU Storing Vegetables and Fruits at Home
  • ·         Also old versions of the USDA Agriculture Handbook 66.
Home vegetable storage options, from WSU
Four Sets of Storage Conditions

 By providing storage spaces with 4 types of conditions, 25 crops can be stored.

  • ·         In my chart in Sustainable Market Farming, the Summary column indicates the general conditions needed for each crop, and allocates each crop to one of 4 groups:
  • ·         A= Cold and Moist: 32°F–40°F (0°C–5°C), 80%–95% humidity — refrigerator or winter root cellar conditions. Most roots, greens, leeks
  • ·         B= Cool and Fairly Moist: 40°F–50°F (5°C–10°C), 85%–90% humidity — root cellar. Potatoes
  • ·         C= Cool and Dry: 32°F–50°F (0°C–10°C), 60%–70% humidity — cooler  basements and barns. Garlic and onions
  • ·         D= Warm and Dry to Fairly Moist: 50°F–60°F (10°C–15°C), 60%–70% humidity — basements. Sweet potatoes and winter squash.
Our winter squash storage cage. Photo Twin Oaks Community
Winter squash and pumpkins – storage

We built a rodent-proof cage with wood shelves. You could use shallow crates to avoid handling each individual squash.

In-ground protected vegetable storage. WSU
In-ground storage

Depending on the severity of your winter, some cold-hardy root crops (turnips, rutabagas, beets, carrots, parsnips, Jerusalem artichokes and horseradish) and also leeks can be left in place in the ground, with about 12” (30 cm) of insulation (straw, dry leaves, chopped corn stalks, or wood shavings) added after the soil cools to “refrigerator temperatures.”

 Hooped rowcovers or polyethylene low tunnels can keep the worst of the weather off. There could be some losses to rodents, so experiment on a small scale the first winter to see what works for you. We have too many voles to do this with carrots or turnips.

Besides being used as a method for storage of hardy crops deep into winter, this can be a useful method of season extension into early winter for less hardy crops such as beets, celery and cabbage, which would not survive all winter this way. Access to crops stored in the ground is limited in colder regions — plan to remove them all before the soil becomes frozen, or else wait for a thaw.

Vegetable storage clamp WSU
Storage clamps (mounds)
  • Cabbage, kohlrabi, turnips, rutabagas, carrots, parsnips, horseradish, Jerusalem artichokes, salsify and winter radishes (and any root vegetables that can survive cold temperatures) can be stored with no electricity, by making temporary insulated outdoor storage mounds (clamps).

Mark a circular or oval pad of soil, lay down straw, pile the roots up, cover them with straw and then with soil, digging a drainage ditch round the pile. For ventilation, leave a tuft of straw poking out. Slap the damp soil in place to protect the straw and shed rainwater.

For the backyarder, various roots can be mixed, or sections of the clamp can be for different crops. Those growing on a large scale would probably want a separate clamp for each crop. It is possible to open one end of a clamp or pit, remove some vegetables, then reseal it.

 There is a balance to be found between the thermal buffering of one large clamp and the reduced risk of rot that numerous smaller clamps provide.

WSU vegetable storage in a buried bin.
Pits and trenches

Dig a deep, wide pit (3+ feet deep) in a dry area where water will not stand, lining it with heavy plastic and straw. Alternate layers of vegetables with layers of straw, finishing with straw. Put a loose sheet of plastic on top, (not sealed down). Cover with more soil.

To deter rodents, bury large bins such as (clean) metal trashcans, layer the vegetables inside with straw, and cover the lid with a mound of more insulation and soil.

Or bury insulated boxes in the ground inside a dirt-floored shed or breezeway. A new life for discarded chest freezers! Insulated boxes stored in unheated areas need 6-8” (15–20 cm) of insulation on the bottom, sides and top.

Root Cellars for crops needing cool, damp conditions

  • ·         Potatoes do best in a dark cellar, at 40° – 50°F (5° -10°C). With a good in-ground root cellar, potatoes store for 5-8 months. Ventilate as needed, to maintain the cellar in the ideal range.
  • ·         Below 40°F (5°C) the starches convert to sugars, giving potatoes an unpleasant flavor and causing them to blacken if fried.
  • ·         Root cellars can be used for apples, cabbage, or root vegetables, but be careful what you mix.
  • ·         Some people pack the unwashed roots in boxes of sand, wood ash, sawdust or wood chips. Perforated plastic bags or crates are easier.
  • ·         Pepper plants can be hung upside down in a cellar to ripen, or store. Cabbage can also be hung upside down.
  • ·         Cabbage, celery, leeks can be replanted side by side in boxes or tubs of soil.
Our root cellar for potatoes. Photo McCune Porter
Ethylene

Ethylene is generally associated with ripening, sprouting and rotting. Some crops produce ethylene gas while in storage — apples, cantaloupes and ripening tomatoes all produce higher than average amounts. Environmental stresses such as chilling, wounding and pathogen attack can all induce ethylene formation in damaged crops. Some crops, including most cut greens, are not very sensitive to ethylene and so can be stored in the same space as ethylene-producing crops. Other vegetables, however, are very sensitive to the gas and will deteriorate in a high-ethylene environment. Potatoes will sprout, ripe fruits will go over the top, carrots lose their sweetness and become bitter.

 

Vegetable harvests, articles on seed saving and garlic planting, workshop on cover crops.

 

Close up of Cow Horn okra pods.
Photo Kathryn Simmons

There are several aspects of vegetable harvesting. In this post I will look first at maturity indicators, then at four ranges of cold-hardy crops for harvest at various stages of winter, followed by a reminder of the order for harvesting storable crops, according to the coldest temperature they can take. After that I have links to a couple of other websites with great information on these topics, a mention of two articles on seed saving  and one on garlic planting I have in Growing for Market magazine. And a link to a Mother Earth News Fair Online workshop on establishing winter cover crops.

Harvest and Maturity Indicators

Don’t harvest too soon or too late. How do you know when it’s ready to harvest? Different factors are important for different crops. Use all your senses.

  • Size: Cow Horn okra at 5”/13 cm (others shorter), green beans a bit thinner than a pencil, carrots at whatever size you like, 7”/18 cm asparagus, 6”/15 cm zucchini
  • Color: Garden Peach tomatoes with a pink flush. The “ground spot” of a watermelon turns from greenish white to buttery yellow at maturity, and the curly tendrils where the stem meets the melon to turn brown and dry. For market you may harvest “fruit” crops a bit under-ripe
  • Shape: cucumbers that are rounded out, not triangular in cross-section, but not blimps. Sugar Ann snap peas get completely round before they reach peak sweetness.
  • Softness or texture: eggplants that “bounce back” when lightly squeezed, snap beans that are crisp with pliable tips. Harvest most muskmelons when the stem separates easily from the fruit (“Full slip”).
  • Skin toughness: storage potatoes when the skins don’t rub off, usually two weeks after the tops die, whether naturally or because of mowing.
  • Sound: watermelons sound like your chest not your head or your belly when thumped. Try the “Scrunch Test” – press down firmly on the melon and listen and feel for the separation of the ripe flesh inside the melon.

Cabbages are fully mature when the head is firm and the outer leaf on the head is curling back. Ignore the separate “wrapper leaves” when making this judgment. If you need to keep mature cabbage in the ground a few days longer, twist the heads to break off some of the feeder roots and limit water uptake, and they will be less likely to split.

Mature cabbage showing curled leaf on the head.
This educational photo of a split cabbage is provided by Firesign Farm

Broccoli
Select blue-green broccoli heads and harvest them before the flower buds open, but after they’ve enlarged. We press down with finger-tips and spread our fingers to see if the head is starting to loosen.

Young immature broccoli head after rain
Photo Wren Vile

Sweet Corn

Sweet corn will be ready to harvest about three weeks after the first silks appear. Corn is ready when the ears fill to the end with kernels and the silks become brown and dry. An opaque, milky juice will seep out of punctured kernels. You can use your thumbnails to cur through the husk on the side and view the kernels. Don’t make your cut on top of the ear, or the dew and rain will get in and rot the corn.

Sweet corn ears are mature when the silks die and turn brown. Photo Kathryn Simmons
Mature Sweet corn ear.

Garlic

Garlic is ready to harvest when the sixth leaf down is starting to brown on 50% of the crop. See Ron Engeland’s Growing Great Garlic. Harvesting too early means smaller bulbs (harvesting way too early means an undifferentiated bulb and lots of wrappers that then shrivel up). Harvesting too late means the bulbs may “shatter” or have an exploded look, and not store well.

Cut across hardneck garlic – airspaces around the stem show maturity

Music garlic cut open showing gaps around stem – a sign of maturity.
Photo Southern Exposure Seed Exchange
Garlic bulb cut horizontally to check maturity (good now or soon).
Photo Wren Vile

Onions

Wait until the tops fall over to harvest, then gently dig up the whole plant and dry. Leave the dry, papery outer skin on the onion for protection.

Onions curing and drying in strings. Photo by Southern Exposure Seed Exchange

Four Ranges of Cold-Hardy Crops for Harvest at Various Stages of Winter

  1. Crops to keep alive into winter to 22°-15°F (-6°C to -9°C), then harvest. Harvest and use soon: Asian greens, broccoli, cabbage, chard, lettuce, radishes. Harvest and store: beets, cabbage, carrots, celeriac, kohlrabi, winter radish (including daikon), rutabagas, turnips. Many greens and roots can survive some freezing, so it is worth experimenting to find how late you can keep crops outdoors.
  2. Hardy winter-harvest crops: cabbage (Deadon), carrots, collards, kale, leeks, parsnips, scallions, spinach. We grow our winter-harvest crops in our raised bed area, which is more accessible in winter and more suited to small quantities.
  3. Overwinter crops for spring harvests before the main season. Some crops, if kept alive through the winter, will start to grow again with the least hint of spring weather and be harvestable earlier than spring plantings. Depending on your climate, the list can include carrots, chard, chicories such as radicchio and sugarloaf, chives, collards, garlic, garlic scallions, kale, lettuce, multiplier onions (potato onions), scallions, spinach. In mild areas, peas can be fall sown for a spring crop. Sow 1″ (2.5 cm) apart to allow for extra losses.
  4. Winter hoophouse crops: The rate of growth of cold-weather crops is much faster inside a hoophouse than outdoors. The crop quality, especially with leafy greens, is superb. Plants can tolerate lower temperatures than outdoors; they have warmer soil around their roots, and the pleasant daytime conditions in which to recover. Salad greens in a hoophouse can survive nights with outdoor lows of 14°F (–10°C) without inner rowcover.

In my post Root Crops in October, I gave this list of storable crops in the order for harvesting, related to how cold they can survive.

Clear and store (in this order):

  • Sweet potatoes 50°F (10°C)
  • “White” Peruvian potatoes 32°F (0°C) approximately
  • Celeriac 20°F (°C)
  • Turnips 20°F (°C)
  • Winter radish 20°F (°C)
  • Beets 15-20°F (°C)
  • Kohlrabi, 15°F (°C)
  • Carrots 12° F (°C)
  • Parsnips 0°F (°C)

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Here are some links to a couple of good sources for more harvest information:

  1. Piedmont Master Gardeners Garden Shed Newsletter

Guidelines for Harvesting Vegetables by Pat Chadwick

A list of seven basic principles of harvesting, followed by a crop-by-crop list of almost 50 individual crops and a resource list of 18 publications (focused on the mid-Atlantic and Southeast)

  1. October Tips from Harvest to Table, by Steve Albert covers all climate zones and comes complete with a USDA Hardiness Zone Map

Prepare your garden for colder weather, plant winter crops where there is still time, harvest crops that will suffer from cold, construct low tunnels with rowcover or clear plastic to keep crops somewhat protected from wind and cold temperatures

Links to other posts by Steve Albert

How to Prepare a Winter Vegetable Garden

Predicting Frost in the Garden

Garden Tips for October


Growing for Market articles

Harvesting seeds this fall?

I have written articles for Growing for Market magazine about growing and saving seeds (August and September issues), and planting garlic (October issue).

Given the shortages of some varieties this spring, it wouldn’t surprise us if more people tried producing seeds of vegetable or flower varieties this year. Here are links to articles from the August and September magazines, covering wet and dry seed processing.

Roma tomatoes cut in half for seed extraction.
Photo Pam Dawling

Wet seed processing and saving

Wet seeds are embedded in fruit. Wet processing has four steps: scooping out the seeds or mashing the fruit, fermenting the seed pulp for several days, washing the seeds and removing the pulp and then drying the washed seeds.

Read the article “Wet seed processing and saving”

Dry seed processing and saving

Dry seeds develop in pods, husks or ears, and dry on the plant rather than inside a fruit. While you obviously want to get seeds into the hands of growers before they need to plant, and into seed catalogs before they get printed, often there is no urgency to extract the dry-seeded crops from their pods. You can wait for a slower time, or use seed cleaning as a rainy-day job.

Read the article “Dry seed processing and saving”

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Mother Earth News Fair

I have a workshop on Winter Cover Crops for Gardeners as part of the Mother Earth News Fair Online Winter Gardening Course. The Winter Gardening Course features 7 videos, each 21-44 minutes long. Mine’s 32 minutes on cover crops.

You can enroll for the 8-course Winter Gardening Course for $20.

Or choose the 2020 all-access course bundle of 21 courses (over 100 videos) for $150.

 

 

 

 

 

 

 

 

 

 

Book Review: Soil Science for Gardeners, by Robert Pavlis

Book Review: Soil Science for Gardeners, by Robert Pavlis, New Society Publishers, 2020. 228 pages, with charts and diagrams, $18.99.

I recommend this book to all gardeners who have hesitated to open a soil science text for fear of dry incomprehensible overloads of numbers. Robert Pavlis explains how your garden grows, and dashes cold water on false myths that may have been wasting your time and limiting your success for years! He leads us to a better understanding, including on a microscopic level, of soil biology, chemistry, physics, geology and ecology and to a place of wonder and curiosity at the everyday functioning of crops and soils.

This new comprehension can lead us to do right by our plants and our gardens, leading to healthier plants and higher yields. Robert writes in plain language, as a gardener with over 45 years of experience. He is the author of those Garden Myths books you might have seen. Perhaps, like me, you paid them little attention, thinking your own knowledge was fact-based. Even so, like me, you might find you had been holding onto some anti-facts (mine was that I believed compost is acidic – not so!). This book aims to have us understand real soil and make real improvements, via a Soil Health Action Plan at the end of the book.

The three sections of the book are Understanding Soil, Solving Soil Problems, and A Personalized Plan for Healthy Soil. A satisfying, logical sequence. Read the sections in the order presented! Robert says it’s very easy to grow plants if you understand the soil which anchors them, feeds them and provides the air and water they need to survive. With a solid understanding of what’s going on, you won’t need to memorize rules.

The 2016 definition of soil, by the Soil Science Academy of America is “Soil is the top layer of the Earth’s surface that generally consists of loose rock and mineral particles mixed with dead organic matter.” A rather bland underselling of what soil accomplishes. Here comes myth-bust #1: “Soil is not alive. It does not need to eat or breathe.” “The whole idea that soil is a living organism that requires similar attention to animals is completely false and leads to many poor recommendations for managing soil.” No, don’t give up here! It’s not the soil but the ecosystem of the soil and all the living organisms in and on it that holds the life. The ecosystem contains life, but is not itself alive.

Air and water are critical for good plant growth, about 25% of each. A simple, startling truth. The sand, silt and clay we might worry about make up another 45%, and 5% organic matter might fill out the total. A large tree can remove up to 100 gallons (400 liters) of water a day, discharging most of it into the air as water vapor. As the water leaves the soil, air is pulled in to fill the spaces. Roots pull the oxygen in, day and night, to convert sugars into energy. Were you also lead to believe that plants photosynthesized by day and respired only by night?

Did you know (I hadn’t thought about it) that “soil pH” is really an average of the pH of the water in the soil, and a spot with organic matter and lots of bacterial activity will have a very different pH from a spot with less organic matter? The rhizosphere (the area right around a plant’s roots) can have a very different pH from the soil solution further away. Plants can grow in alkaline soil because their roots are actually growing in acidic conditions. The nitrogen-fixing bacteria on legume roots cause the plant to release hydrogen ions, making the rhizosphere more acidic. To some extent, our efforts to change the soil pH can be undone by our crops and weeds! A soil property called buffer capacity lets the soil absorb materials at different pH and maintain its same level. Peat moss is acidic, but it does not acidify alkaline soil. The soil in the rhizosphere can be 2 pH units different from the soil around. This is usually written about in rather magical terms, but here it is in plain language.

Roots grow just fine where there is enough phosphorus. Adding more at transplanting doesn’t help, and can hinder. Visual plant symptoms can predict possible deficiencies, but are not a reliable diagnosis. Purple leaves may indicate phosphorus deficiency or cold temperatures, high light intensity, pest damage or lack of water. Or a nitrogen shortage reducing the plant’s ability to absorb phosphorus. There’s much that we don’t know!

Pay attention to the Cation Exchange Capacity – the measure of the soil’s ability to hold cations – because many plant nutrients are cations. You can increase the CEC by increasing the clay content, increasing the OM or increasing the pH. Read more in this book.

Have you ever thought about the “free” nitrogen from legume root nodules? Rethink of it as “homegrown” or “solar” rather than simply magic and free, because the leguminous plant may use up to 20% of the sugars produced during photosynthesis, to feed the bacteria.

Don’t justify your adherence to organic gardening by falsely claiming that synthetic fertilizers kill bacteria. Bacteria feed on both synthetic and organic fertilizers. This book challenges us to find the factual basis for choosing to grow organically, making us stronger advocates.

Hoophouse bed broadforked to aerate the soil without inverting.
Photo Pam Dawling

The bacteria chapter is followed by a chapter on fungi. Fungal spores are everywhere, even the Antarctic. Fungi are crucial for cleaning up plant litter on the soil surface. They grow above-ground hyphae which can penetrate dry leaves or wood chips and move the nutrients deep into the soil. Bacteria can’t tackle such tough stuff! 150 species of fungi capture and digest nematodes.

Why is organic matter important?  This chapter explores the chemical and biological effects of organic matter on soil. Soil contains three forms of organic carbon: the living (15%), the dead and the very dead (stable humus and charcoal). Increasing the level of organic matter in the soil can increase aggregation, improve water infiltration (reducing runoff), increase aeration, increase water-holding capacity, improve tilth of clay soils, reduce crusting, and improve the size and distribution of the pore spaces. Those are just the physical effects. It will also increase the cation exchange capacity, increase the availability of nitrogen, boron, molybdenum, phosphorus and sulfur, and increase the microbial activity and diversity.

Often we think about adding partially decomposed OM such as compost and manure. We should face the reality that compost tends to have low levels of nutrients (maybe 1:1:1).   The big value of these is in providing food for microbes, short-lived beings that provide a constant supply of fresh OM, multiplying its value. Partially decomposed compost takes about five years to finish decomposing, during which time it slowly releases nutrients. This gradual steady supply is what crops need. The humus left at the end is a complex molecular mixture of carbon, hydrogen and oxygen, resistant to further decay.

The initial effect of adding fresh OM (not composted OM) is an explosion of microbial reproduction, feeding and death. The microbes use nitrogen, which can cause plants to suffer a shortage. It takes time for a new balance to be achieved, providing adequate N for the plants.  The needs for the N can encourage gardeners to add so much compost that the P level is too high, which can bring death to mycorrhizal fungi, leading to roots driving deeper to access their own P from the soil directly. We have very high soil P, a result of misunderstanding soil test limits. I have worried about it, then read more and stopped worrying. Soil P is pretty stable. If you are not leaching P into a waterway, it just stays in your soil until a plant need it. We switched to using less compost and more cover crops where we could. We were already using a lot of cover crops – it’s not like we were slouches in that department! After more time, I settled on accepting our situation, and as the plants show no sign of P-caused problems and our soil is bursting with earthworms, it doesn’t affect us much.

I mentioned at the beginning that I learned that finished compost is alkaline, not acidic. In the initial composting stage, acidity happens. Then fungi thrive, and decompose the tough lignin and cellulose, causing the pH to rise and bacteria to take over. Compost-making has lots of myths! Poorly understood science makes them grow, I suppose. Bokashi composting, for example (more of a fermentation than a composting process) is based on the idea that fermented material decomposes faster, although it’s unclear if this is really true. “The best method of composting is the one that you do and continue to do because you like doing it. Any form of composting is better than taking yard waste to the curb.”

The Rhizosphere chapter is fascinating! Root exudates can restrict the growth of competing roots, attract microbes into symbiotic relationships, Change the chemical and physical properties of the soil solution and the soil, and make nutrients more available. Bacteria make explosive population growth as they feed on exudates. Then their predators, nematodes and protozoa, join the party. The soil water around the roots becomes a nutrient soup. By photosynthesis, the plants produce the attractive exudates that the soil food web turns into plant nutrients right where the roots can efficiently hoover them up. Plants are active in seeking nutrients, not passive recipients. Not to say they have knowledge, or think and plan. It’s a matter of chemical reactions controlled by enzymes with the capacity to change their activity based on the presence or absence of chemical triggers. Let’s marvel at the reality! We don’t need fairy stories!

The second section of the book, Solving Soil Problems, starts with identifying the problems, and works through techniques affecting the soil, chemical and microbe issues, increasing organic matter and structural problems. We are not feeding plants, we are replacing missing nutrients in the soil, so they can take the nutrients they need. The solution will depend on your soil, so a “tomato fertilizer” is not going to be what tomatoes need in every soil. If you plan to top up the missing nutrients, get a soil test to learn what those are. But if you plan to apply manure or compost everywhere as your only amendment, your money is wasted on a soil test. If you add compost every year and return cover crops, organic mulch and your plant debris to the soil, and your plants are mostly growing well, you probably don’t need to add any other fertilizer to your garden. This alarmed me a bit. What about boron shortage, which happens here? Yes, if you are a farmer or market gardener, yields do matter and soil tests (free for commercial growers in Virginia) will be worthwhile. But for a home gardener, or a landscape gardener, yields might not be at the top of your list. Robert explains various tests, and gives his take on how useful they are. The information here can save a lot of confusion and wasted effort.

Photo by NCSU Crop Soil Undergrad course

In the techniques chapter, the author explains the dramatic difference in available nitrogen in a cultivated garden and a no-till one. No-till can supply up to five times the nitrogen, because tilling adds more air into the soil, increasing the microbial activity, burning up the OM. There is a useful chart comparing the effects of fertilizer, compost and wood chips on the soil. We’ve all learned not to bury wood chips in the soil, where they use up the nitrogen while decomposing. But on the surface they can do wonders.

Crop rotation has come under scorn recently from commercial growers who are focused on maximizing yield and profit for their time on small areas of land. Sure, salad mix and baby spinach can rake in the money. But generations of farmers have learned to grow different types of crops each year in a particular spot. This can increase yields 10-25%, even though we are not sure why. Studies have shown it’s not simply nutrient availability. It could be pH changes freeing up more nutrients, or microbe biodiversity, or differing root growth granting access to more depth than the current crop alone can achieve. Rotated crops are more drought resistant and make better use of nitrogen. Research is needed.

As I was happily digesting this book I was brought short by this mnemonic that still puzzles me: “If you have trouble remembering whether P stands for phosphorus or potassium, remember that these nutrients are listed in alphabetical order. Phosphorus comes before potassium in the alphabet, and so P comes before K.” Um, K comes before P, last time I looked. Confusing.

Does rock dust add nutrients? No evidence, says Robert. Do not be beguiled by mineral products claiming to add 74 minerals to your soil. Plants might only use 20 of them. More is not better! Beware fad products such as biostimulants and probiotics. Plants cannot use vitamin B1. What about compost tea? Yes, it adds nutrients, but claims that the included microbes work wonders are not supported by science: test results are very mixed, including worse. Sometimes we are too gullible! Milk, molasses: they add nutrients but no special magic. Fermenting something cannot add nutrients – it could make some more available, although that isn’t proven either. The fungal and bacterial populations increase, but are the species nutritious ones or pathogenic ones?

Photo by Usu.edu Soil 1

The gardener’s goal is to farm healthy microbes, even though they are too small to see. Use the state of the soil and the health of the plants as indicators of the health of the microbes. Supply OM, water and you’re on the right track. It has been proved useful to add rhizobium legume inoculant if you haven’t grown legumes for some years. Fungal inoculation of soybeans in low phosphorus soil will be effective. Not otherwise.

The author’s general practice is to improve the soil environment to help existing microbes. There is a list of 7 general ways to do that. There is a whole chapter on increasing OM, using what’s local and cheap. Coir is a waste product, but its production causes environmental damage to local water supplies (large amounts of sodium have to be leached out).

Biochar, one of the new “Garden Wonders”, has claims to make big improvements to the soil food web. Most of the biochar studies have been conducted in labs, not on farms. Even then, 50% of the studies report higher yields, 20% report no change, and 30% report a decrease. There are probably better ways to spend your money!

What about gypsum? I believed the common advice to use it to break up clay soils. Mostly this myth is not supported by evidence. Gypsum can have some negative effects. Add more OM instead. Likewise for improving sandy soils: add more OM.

The final section of the book is a set of worksheets and instructions to help gardeners improve the soil health where they are. This is a slow process, so start soon! Robert has also made the forms available on his website www.gardenfundamentals.com/soil-book-forms. First assess your soil, then make an action plan, then record your progress.

I recommend this book for all sustainable/regenerative/organic gardeners and small-scale farmers, and even large-scale farmers who realize there are gaps in their understanding of soil science. This book is very accessible, user-friendly and full of soil-based common sense. Winter is a good time to make new plans!

Robert Pavlis has two websites: www.gardenmyths.com and www.gardenfundamentals.com as well as a YouTube channel www.youtube.com/Gardenfundamentals1

Planning to grow potatoes again

Planning to grow potatoes again 

Potato plant emerging in spring.
Photo Kathryn Simmons

This is the last part of a monthly series on growing potatoes, a dietary staple.

I have a whole chapter about potatoes in Sustainable Market Farming, where the basics of potato growing can be found. Below are more details about growing potatoes that you may not have wanted or needed this year. Use your own records and this information to plan for bigger harvests, at times of year suited to your farm.

Varieties

Some varieties store better than others, so advance planning will help achieve good results. Scrutinize the small print in the seed catalogs before your next seed order.

Covering a row of seed potato pieces aligned under a rope.
Photo Ira Wallace
Photo Ira Wallace

Potato types: determinate and indeterminate

We have mostly grown Red Pontiac, Yukon Gold and Kennebec. They all seem to be determinate varieties — they grow as a bush, then flower and die. I only learned this year that there are determinate (varieties with naturally self-limiting growth, generally “early” varieties) and indeterminate varieties (such as “Russet Nugget,” “Nicola,” “German Butterball” and “Elba”). The distinction is explained in Potato Bag Gardening. Growers using towers, grow bags, and cage systems want indeterminate potatoes, which continue to produce more layers of tubers on the stems as they are progressively covered with more soil. Growers wanting a fast reliable crop in the field mostly choose determinate types, which grow as a bush, then flower and die. The Internet does seem to have some contradictory statements about which varieties are determinate and which indeterminate, and some dedicated container growers make assertions not supported by experienced commercial growers. So Reader Beware! I trust Extension and here’s a link to their Ask an Expert page on potato types.

Crop rotation, including cover crops

This is very important for potatoes, which are nightshades like potatoes, peppers and eggplant. Colorado potato beetles emerge from the soil in spring and walk (they don’t fly at this stage) towards the nearest nightshades they can detect. Give them a long hike! A distance of 750′ (230 m) or more from last year’s nightshade plots should keep them away. A three- or four-year rotation out of nightshades in each plot is ideal.

Suitable cover crops before potatoes include brassicas (which can help reduce root knot nematodes and Verticillium), Japanese millet (which can reduce Rhizoctonia) and cereals in general. Beware beets, buckwheat and legumes such as red and crimson clovers, and some peas and beans, as these can host Rhizoctonia and scab.

Late corn undersown with oats, mowed high in October to deal with weeds, and the ex-sweet potato patch sown in winter wheat and crimson clover. Credit Ezra Freeman

In our ten year crop rotation, our March-planted potatoes follow a winter of oats and soy (which winter-kill in our zone 7a climate). This cover crop is undersown in our late sweet corn about 30 days after sowing. Our June-planted potatoes follow a winter cover crop mix of winter wheat or winter rye and crimson clover. This mix is sown in early-mid October after our middle planting of sweet corn. (Yes, we risk the clover.) We had read that potatoes are said to do well after corn, so when we set up our crop rotation, that’s what we did. I have no scientific proof that the assertion is true, but we often have good potatoes, so at least it does no obvious harm!

Fall broccoli transplanted after July potato harvest, and undersown with a mixed clover cover crop.
Photo Nina Gentle.

After harvesting our March-planted potatoes in mid-July, we regularly did a fast-turnaround and transplanted our fall broccoli and cabbage in late July. We undersowed that with a clover mix 4 weeks after planting the brassicas. We kept the clover mix for an all-year Green Fallow, right round until the February a year and a half later. This fast-turnaround was a bit nerve-wracking, so we no longer do that, simply following the potatoes with the clover mix, while transplanting the brassicas in another plot.

After harvesting our June-planted potatoes in October, we sow winter wheat or winter rye with crimson clover or Austrian Winter Peas, depending when we are ready to sow. (Wheat and clover if by 10/15, rye and peas if later)

Preparing the Soil

A bed ready for tilling after mowing the cover crop and spreading compost.
Photo Pam Dawling

Potatoes benefit from generous amounts of compost or other organic matter (they use 10 tons/ac, 22,400 kg/ha) and will grow in soils with a pH of 5.0–6.5. They use high amounts of phosphorus (P) and potassium (K), and need adequate soil levels of iron and manganese. They are less affected by low levels of copper and boron. Hay mulch can be a good source of K. As Carol Deppe points out, potatoes will still produce an OK crop in poor soil, where you might not be able to grow much else. See the ATTRA publication Potatoes: Organic Production and Marketing.

Dormancy

See Part 5, Storing Potatoes, for an introduction to this topic. When potatoes sprout and whether they grow one or more sprouts, can be controlled by manipulating the storage conditions.

For extra-early spring planting, aim to sprout relatively few eyes per potato, so that relatively few shoots will grow and the seed pieces will be big enough, with enough nutrients for the plants. Do this by priming the seed potatoes at 65°F (18°C) until the eyes at the rose end just start to sprout. Store at 45°F (7°C) until two weeks before planting time, then finish the sprouting in warmth and light. The early sprouting of the rose-end eyes suppresses the sprouting of the other eyes. If needed, break off extra sprouts before planting.

To avoid sprouting, keep the potatoes below 50F (10C) once they are more than a month from harvest, avoid excess moisture, and avoid “physiological aging” of the potatoes, caused by stressing them with fluctuating temperatures, among other things. If eating potatoes do start to develop sprouts, it’s a good idea to rub off the sprouts as soon as possible, because the sprouting will produce ethylene, which will encourage more sprouting.

Physiological age of seed potatoes

Seed potatoes can act differently depending on their “physiological age.” The warmer the conditions are after dormancy ends, the quicker the sprouts grow and the faster the tubers “age.” When we buy seed potatoes the storage conditions they have already received are beyond our control. As a guide, the length of the longest sprout, and the number of sprouts are measures of physiological age (if the sprouting has taken place in the light). Varieties do not all show these effects to the same degree.

Don’t let your potatoes sprout in storage
Photo Jesse Strassburg

Deliberately adjusting storage temperatures is a way of manipulating the physiological age, in order to get higher yields or earlier maturity. To age seed potatoes, buy the seed in late fall or early winter before they break dormancy and store them rose (eye) end up in daylight at 50°F (10°C) until just before the planting date. In spring, reduce the temperature just before planting, to minimize the thermal shock from the cold soil.

Physiologically “young” tubers will have just one or two sprouts, due to apical dominance (when the leading bud inhibits the other eyes from developing shoots). The plants will have fewer stems, leading to fewer, but larger, potatoes. They will need longer to grow, and so give a later harvest. If you hurry and dig them early, you will only get low yields.

“Middle-aged” tubers give the best yields (27% higher than young or old tubers). “Middle-aged” seed potatoes have multiple short sprouts, without the hairy look of “old” ones. The pre-sprouting instructions given in Part One: Planting potatoes aim to produce “middle-aged” seed.

Physiologically “old” seed potatoes will have many “hairy-looking” branched sprouts, coming from eyes all over the potato. These potato plants emerge faster and start tuber formation sooner. The final plant size will be smaller (because the shoots are weak) and the plants will be more susceptible to drought and die sooner. Because the tubers do mature quickly, they may be good if you seek an early harvest, or are planting a fall crop a bit too close to the frost date. The total yield will be lower (but earlier) than from “younger” seed.

See the University of Maine Extension Service Bulletin #2412, Potato Facts: Selecting, Cutting and Handling Potato Seed  Their drawings are reproduced here. Also see Know and Grow Vegetables by Salter, Bleasdale, et al. for more on this complex topic.

More POTATO resources

The University of Maryland Extension Home and Garden Info Center Potatoes

University of Maryland IPM series on potatoes, which is a troubleshooter sheet on causes and solutions for problems

Cornell 2016 Organic Production and IPM Guide for Potatoes (104 pages)

The Potato Association of America, Commercial Potato Production in North America 2010. (90 pages)

The Government of Canada Biofungicides provide Post-harvest Disease Protection in Potatoes

Other related Blog Posts

Potato Research on Harvest and Storage

What Makes Potatoes Sprout, Nov 2017

How to Deal with Green Potatoes (one of my most-read blog posts!)

Green Potato Myths and 10 Steps to Safe Potato Eating in Mother Earth News