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!
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.
Organic Growers School 28th Annual Spring Conference
Online, March 13-21, 2021
The Organic Growers School Spring Conference 2021is 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
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:
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.
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!
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.
Articles in Mother Earth News
I have an article coming up in theMother 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.
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.
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” .
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.
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.
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
An extended growing season because plants are protected from cold weather.
Faster growth and higher total yields.
Beautiful unblemished crops not battered by the elements.
Fewer foliar diseases because the leaves can stay dry.
Crop survival at lower temperatures in the hoophouse than is possible outdoors.
Better crop recovery in winter due to warm sunny days following the cold nights.
Some protection from deer and other pests large and small.
Soil temperature stays above 50F (10C) in zone 6b. Warm soil = faster cold weather growth.
Higher proportion of usable crops – more food, higher sales dollars.
Diverse crop portfolio – grow crops that wouldn’t succeed outdoors in your climate.
Harvest whenever you need the crops, even during pouring rain!
Wonderful working conditions – no need for gloves and hats; take off your coat.
A food garden on a manageable scale.
A place to enjoy practicing intensive food production.
The chance to have an area completely free of weeds – new weed seed doesn’t blow in.
No need to work with heavy machinery.
Much better value for producing crops (per dollar invested) than a heated greenhouse.
Can be constructed by generally-handy people. Specialists are not needed.
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.
Know your climate
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.
Winter gives a time for most of us to ponder success, failure, and possibilities for doing things differently.
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.
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.
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.
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.
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.
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;
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:
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 Assessmentreleased 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.”
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.”
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.
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)
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.
Root Crops to Harvest in Central Virginia in November
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.
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.
Other Root Crop Tasks in Central Virginia in November: Long term storage of sweet potatoes and white 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
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’sStoring 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.
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
·C=Cool and Dry: 32°F–50°F (0°C–10°C), 60%–70% humidity — coolerbasements 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.
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.
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.
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.
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.
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.
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.
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.
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.
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
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.
Four Ranges of Cold-Hardy Crops for Harvest at Various Stages of Winter
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.
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.
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.
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)
Here are some links to a couple of good sources for more harvest information:
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
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.
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.
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.
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.
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.
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?
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!
PART SIX: Planning to grow potatoes again (September)
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.
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.
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.
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!
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
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.
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.
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.
Cuban AgroEcology Tour: La Palma farm, Pinar del Rio Province
Here’s another post about the Organic Growers School Agroecolgy Tour I participated in back when we could travel! I feel so fortunate to have made this trip this January. You can read about other parts of this Tour under the Cuban Agriculture category or at these links:
After our initial stay in Havana, we traveled west for three hours to stay a few days in the Viñales Valley in the province of Pinar del Rio.
Day 5 – Saturday January 11, morning
Our day started with an 8 am breakfast at our casa particulare in Viñales. We enjoyed fruit, tea, coffee, juice, cookies, bread, pancakes, cheese sandwiches, and ham. No eggs today.
We took our tour bus to visit the ANAP (National Association of Small Farmers) cooperative agricultural project La Palma. ANAP farmers have less than 67 hectares each. According to Wikipedia, currently ANAP members produce 52% of the vegetables, 67% of the corn, and 85% of the tobacco grown in Cuba.
We met tobacco producers Roberto and Eduardo, who are brothers. Each farm is allowed a certain tobacco quota by the Cuban government. They are growing 40,000 tobacco plants as their quota and another 40,000 using a neighbor’s irrigated land in trade for their use of some dry land. Tobacco needs irrigated land, and their neighbor did not have the other resources to grow a tobacco crop this year. The government agreed to this swap because of the poor state of the national economy.
La Palma also grows vegetables (tomatoes, beans with some interplanted corn plants to protect the beans from pests), and cassava. They use oxen for cultivating the fields. We had some juice, a taste of red mamey fruit (Pouteria sapota), and the chance to buy cigars for $2 each.
Next we paid a visit to a farm with a small cigar manufacturing business, Manolo Tobacco Farm, for a demonstration of cigar-making, and a chance to buy different kinds of cigars. All the cigars are rolled by hand and the men demonstrating the technique are also professional in engaging the audience. After rolling a cigar for us, the demonstrator lit it, showed how to smoke cigars and passed it round.
See this video of cigar making at Manolo Tobacco Farm, made by Franny’s Farmacy, two of the other people on my Organic Growers School Tour:
At this place I was dismayed to find a nasty toilet (not the first of this trip): no seat, no paper, no flush. The toilet tank was not connected to a water supply. The water at the sink was very slow, and even though a bucket was provided, filling it to flush the toilet seemed very challenging. How can a tourist attraction have such terrible toilets? Why are there not more composting toilets?
Cuba, at least in the northwest, suffers from a shortage of water, and ancient mainline plumbing that leaks a lot. When we arrived at the José Martí International Airport in Havana, an announcement came over the loudspeaker that the water supply had been temporarily shut off to the restrooms. Havana has a natural port, but no river drains into it. See Rivers in Cuba map to appreciate the unfortunate geography!
The Albear Aqueduct was constructed in Havana in 1858, in a neoclassical style and still supplies 20% of Havana’s water. A marvel of mid-19th century engineering, the water comes from the de Vento springs by gravity. This fresh water helped the city reduce the terrible cholera epidemics and earned a gold medal at the 1878 Paris Exposition
Sow summer cover crops while it’s still too early sow your winter cover crops. Sow oats 5-8 weeks before your average first frost to get good size plants before they get winter-killed. Sow winter rye from 14 days before to 28 days after first fall frost. Oats, barley, wheat and rye sown too early can head up and seed before you get to winter, making them less useful. Instead, sow fast-growing summer cover crops in any space possible, for weed suppression and a boost to soil organic matter.
Keep live roots in the ground as much of the time as possible, to feed the microorganisms and anchor the soil, preventing erosion in heavy rains. Dead roots also have a role, providing drainage channels in the soil and letting air in deeper. Adding organic matter to the soil is a way of banking carbon, as well as providing nutrients for your crops.
Deep-rooted cover crops draw up nutrients, bringing them up where crop plants can access them. Leguminous cover crops provide nitrogen, saving imports of organic fertilizers or a big compost-making operation.
Advantages of Summer Cover Crops
Suppressing weeds. Weeds grow fast in summer, and fast-growing summer cover crops will suppress them. Sowing cover crops helps us stay on top of developing problems.
Growing biomass. Many summer cover crops can be mowed or scythed down (before flowering) to encourage regrowth. The cut biomass can be left in place, or raked out and used as mulch in another part of the garden. Some can even be used as feed or bedding for small livestock.
Feed the soil life. Cover crops are solar-power generators, transforming sunlight, water and carbon dioxide into leaves and roots. They also release carbohydrates and other nutrients that feed soil microbes, earthworms and other soil life forms that make soil fertile. This cycle of nutrients constantly passes through plants and back into the soil. When you aren’t growing vegetable crops, cover crops keep this cycle going.
Increasing biodiversity. Cover crops can attract beneficial insects, birds and amphibians to feed and reproduce. Biodiversity encourages ecological balance that can help reduce plant diseases and pest attacks.
No-Till summer cover crops. A mix of soybeans or southern peas and foxtail millet can be grown during the summer and mow-killed before planting in the fall. Garlic perhaps?
Overcoming the Challenges of Summer Cover Crops
Finding space. If you’ve been carefully filling every space with vegetables, you may think you have no room for cover crops, but because they feed the soil, it’s worth making space for them too. It’s part of the wholistic picture of sustainable food production. It’s worth making a priority to have one bed or one section of your garden in cover crops, because of what they can do for your soil.
Have a goal of No Bare Soil. Seek out odd spaces to fill with cover crops.
Use space beside rows of sprawly crops short-term. Undersow buckwheat in winter squash, watermelon or sweet potatoes, and mow or till as soon as the vines start to run.
Take a cold hard look at aging crops: better than keeping an old row of beans to pick every last bean, is to pull up those beans and sow a quick cover crop. It will be a more valuable use of the space.
Take a look at your planting plan. When is your next crop going in that space? Rather than till the soil to death to manage the weeds, use a cover crop. In the winter, see if you can re-arrange your crop rotation and planting plan to make more time windows of a month or more, with the plan of using more cover crops.
Undersow growing crops with a cover crop when the vegetable crop has been in the ground for about a month. The food crop will be big enough to resist competition from the cover crop, and the cover crop will still get enough light to grow. This way fewer weeds grow, and your cover crop is already in place when the food crop is finished, giving it longer to reach a good size. We undersow our sweet corn with soybeans (soy and oats for the last sweet corn planting). Buckwheat can be under-sown in a spring vegetable crop, to take over after the food crop is finished. You can plant a short cover crop on the sides of a bed of any tall crop like tomatoes or pole beans. You will need to provide extra water, especially while the cover crop is germinating. Read my Mother Earth News post on undersowing in late summer and early fall.
You can also undersow winter cover crops during late summer and early fall to last over the winter and even the next year. We broadcast clover among our fall broccoli and cabbage with the plan of keeping it growing for the whole of the following year, mowing once a month to stop annual weeds seeding.
High temperatures. Most summer cover crop seeds will germinate just fine at high temperatures provided they get enough water.
Drought. If it doesn’t rain much in your summers, or your irrigation water is limited, choose cover crops that are drought-tolerant once germinated. After sowing, work the seed into the soil and roll or tamp the soil so that the seed is in good contact with the soil, which will help it get the water it needs rather than drying out in an air pocket. To get good germination, keep the soil surface visibly damp. You can use shadecloth, a light open straw or hay mulch, or even cardboard to reduce evaporation. Be sure to check every day and remove the cardboard as soon as you see the first seedlings.
Sowing small spaces. You can sow cover crops in rows by hand in very small spaces, or use an EarthWay seeder. Or you can broadcast: tuck a small bucket of seeds in one arm, take a handful of seeds and throw them up in front of yourself in a fanning movement, trying not to spread seed into neighboring beds where you don’t want them. Aim for about two seeds/sq in (1 sq inch is 6.5 sq cm, I’ll leave you to think what it looks like). Don’t sweat the details, you will get better with practice! This isn’t brain surgery! For more even coverage, try broadcasting half the seed walking up and down the length of the patch, then sow the other half while walking at 90 degrees to your original direction. Rake or till the seeds in, trying to cover most of the seeds with 0.5-1” (1-2.5 cm) of soil. Water with a hose wand or sprinkler to keep the soil damp until germination.
Working with the time you have left.
If you have only 28 days until the patch is needed for a food crop, you can grow mustard or buckwheat. Or weeds, if you’re careful not to let them seed!
If you have at least 45 days, you can grow soy or Japanese millet.
If you have only 40-60 days before frost you can sow oats with soy beans or spring peas as a winter cover crop to winter-kill.
If you have 50–60 days until frost, or between crops, Browntop millet is possible. In the right climate, sunn hemp can mature in 60 days.
With 60–80 days until frost, or between one crop and the next, you could sow buckwheat, soy, southern peas, spring peas, German foxtail millet, pearl millet, Japanese millet, or sorghum-sudangrass to frost-kill. Or you could sow oats with Austrian winter peas, crimson clover, or red clover to grow into winter.
If you have longer than 80 days you can sow any of the warm weather cover crops now and then move on to winter cover crops 40 days before your frost. Or you could sow a fast-growing vegetable crop.
Five Easy Summer Cover Crops that Die with the Frost
Buckwheat is the fastest and easiest cover crop, a 2’-3’ (60-90 cm) tall broadleaf annual that can be flowering within three weeks in very warm weather, 4 weeks in regular warm weather. Because it grows so fast, it quickly crowds out germinating weeds. Plant buckwheat after all spring frosts have passed, until 35 days before the fall frost at the latest.
If you have longer than 4 weeks for cover crops, you have the option of letting the buckwheat self-seed and regrow (only do this if you’ve finished growing vegetables for that year in that space). Another option if you are not close to the frost date is to incorporate the buckwheat in the soil and then sow fresh seed.
Buckwheat is very easy to incorporate into the soil. Use a mower or scythe to cut it down 7-10 days after it starts flowering, and then either let the dead plants die into a surface mulch and plant into that, or rake it up and compost it, or dig or till it into the soil. For small areas, you can simply pull up buckwheat by hand – this is what we do in our hoophouse.
Buckwheat can be used as a nurse crop for fall-planted, cold-tolerant crops, which can be difficult to germinate in hot weather. Sow a combination of buckwheat and a winter vegetable to shade and cool the soil. When frost kills the buckwheat, the vegetable crop can continue growing with no competition.
Buckwheat is not related to any of the common food crops, and so it is simple to include it in crop rotations.
One of our favorite summer cover crops is sorghum-sudangrass, a hybrid that grow 5’-12’ (1.5-3.6 m) tall in 60-70 days and produces an impressive amount of biomass. You’ll need big machinery, at least a big BCS mower, to deal with sorghum-sudangrass. If you have only hand tools and a lawnmower, I recommend growing German foxtail or Japanese millet instead.
Plant sorghum-sudangrass about two weeks after your first sweet corn planting date and anytime onward until six weeks before frost. After it’s established, sorghum-sudangrass is highly drought-resistant and thrives in summer heat. Plant in rows 8” (20 cm) apart, with seeds 1’ (2.5 cm) deep, 1.5” (4 cm) apart. Sorghum-sudangrass will smother weed competition, and make big improvements to the soil texture and the levels of organic matter.
When the sorghum-sudangrass reaches 4’ (1.2 m) tall, cut it down to 1’ (30 cm) to encourage regrowth and more, deeper, roots growth that will loosen compacted soil. The cut tops make a good mulch, or you can leave them in place.
Sorghum-sudangrass roots exude allelopathic compounds that suppress damaging nematodes and inhibit small seeds (weeds and crops) from germinating and inhibits the growth of tomatoes, lettuce, and broccoli. Wait at least 6 weeks after killing sorghum-sudangrass before planting another crop in the same spot. Plant earlier at your own risk – I think we’ve had some success despite the warnings. Be careful if feeding to livestock. Read up about prussic acid poisoning from this cover crop.
These are a quick easy leguminous cover crop for warm weather. Buy organic seed if you don’t want GMOs, as almost all non-Organic soybeans in the US are GMOs. We plant these whenever we have a minimum of six weeks for them to grow before frost or before we’ll need to turn them under. They aren’t the highest N-producing legume, but they are very fast-growing and easy to manage.
Also known as cowpeas, although I have heard this might be perceived as insulting by African-American families who use them as food. Southern peas grow fast (60-90 days), thrive in heat, and are very drought-tolerant. Their taproots can reach almost 8’ (2.4 m) deep. They grow well in almost any soil, except highly alkaline ones. Southern peas attract beneficial insects.
Sow southern peas 1-2 weeks after your sweet corn, when the soil has warmed up. You can continue sowing until 9 weeks before a killing fall frost. Sow seeds 2” (5 cm) apart, 1” (2.5 cm) deep in rows 6” (15 cm) apart (give vining types more like 15” (40 cm) between rows. Close planting is needed to shade out weeds.
Because they are fast-growing, southern peas can follow spring vegetable crops and fix nitrogen in time to feed heavy-feeding, fall-planted onions or garlic.
Sunn hemp is a nitrogen-fixing legume from the tropics, which can grow as much as 9’ (2 m) tall in just weeks. Sow sunn hemp from 1-2 weeks after your sweet corn sowing date, up to 9 weeks before a killing frost. It tolerates a wide range of soils (but not if waterlogged), and dies with the frost. Plant inoculated seed (use the same inoculant as for southern peas) 1” (2.5 cm) deep, with seeds 1.5” (4 cm) apart in the row, and with rows 6” (15 cm) apart. Sowing densely will smother the weeds.
If you sow in a summer gap between spring and fall vegetable crops, it will provide a nitrogen boost for the fall crop. In dense plantings, it can fix more than 120 lbs (54 kg) of nitrogen and 12 pounds of biomass per 100 sq ft (0.56 kg/sq m). 60 days after sowing, the stems thicken and become fibrous and high in cellulose; cutting at this stage produces long-lasting mulches that increase soil carbon. If you cut the crop back at a younger stage, this will stimulate branching (more biomass) and more root penetration (better drainage).
Late Summer Cover Crops for Winter: Oats and Barley
In late summer you can sow oats for a winter cover crop that will be killed at 6°F (-14°C). We sow in late August and early September in Zone 7. Inexpensive and easy to grow, oats are a standard fall cover crop: a quick-growing, non-spreading grass, oats will reliably die in Hardiness Zone 6 and colder, and nine years out of ten in zone 7.
Barley grows even faster than oats, and on average it will get killed later in the winter. It usually dies at 17°F (-8°C), making barley another choice for gardeners in regions where oats are used.
Cover Crop Resources
My book Sustainable Market Farming has a chapter on cover crops and 9 pages of charts about particular options.
The book Managing Cover Crops Profitably (third edition) from the Sustainable Agriculture Research & Education Program (SARE), is the best book I know on the subject. You buy the book for $19 or download it as a free PDF from SARE.
Book Review: Whole Farm Management from Start-Up to Sustainability,
edited by Garry Stephenson et al, Storey Publishers, 2019. 312 pages, 8” x 10” format, full color photos throughout, $26.95
This is an encouraging and inspiring practical resource for beginning farmers and those growing and maintaining a farm business. It uses examples drawn from twelve farms (16 farmers). Nine of the farms are in Oregon, with one each in Missouri, Pennsylvania, and Virginia. As for diversity, three of the twelve farms have people farming while black, one has an Asian-American family, and there is a range of family relationships, including single farmers. What this book is not: how to grow lettuce, how to practice rotational grazing, how to slaughter chickens, how to prune apple trees.
Whole Farm Management is based on the curriculum from the Center for Small Farms & Community Food Systems at Oregon State University. The course is available online, and focuses on small-scale organic and sustainable agriculture through the Extension Service Small Farms Program. Royalties from book sales will support OSU beginning farmer education.
“Operating a farm business requires managing dreams, crops, people, markets, money and reality.” Whole Farm Management blends advice and inspiration from experienced farmers with guidance from ag educators. Recognizing the Manage/Learn/Succeed cycle, one of the farmers advises “You can’t know it all at once. Growing is where it starts. You have to know you can grow something before you can figure out how to sell it. But once you grow it, you have to figure out how to market. And once you’ve sold a few things, then you’re in a position to ask: can I afford to keep doing this?”
The first one to three years of farming are about proving we can grow and sell. The next couple of years are more deliberate, less frantic. The next few years focus on how to make money. After that the question becomes “We can. Should we?” In terms of using the book, if you are in the first few years of farming, you know you can’t learn everything at once. You grab onto the bits of information you know you need. You skip over the things you don’t see an immediate need for. Learning is endless. How do you define success? Success can include the elements of social, operational, lifestyle and financial well-being.
The book follows the logical progression of training used in the OSU Growing Farms program and we can all benefit from following their well-traveled ten-year path. One or two individual farms are introduced in each chapter to illustrate particular points or aspects and the photos draw us in. There are six sections, each opening with a list of what you’ll be able to do after reading that chapter:
Dream It – Strategic Planning. (Values, vision, mission; assessing your resources and needs; creating a foundation that matches your plan with your resources.)
Do It – Farm Infrastructure, Labor and Energy. (How to put your resources – equipment, infrastructure, people, processes – to work.)
Sell It – Markets and Marketing. (Developing a marketing strategy in line with your farm values, vision, mission before deciding what you will grow or raise.)
Manage It – Business Management for the Farm. (Learning to be successful.)
Grow It – Managing the Whole Farm Ecosystem. (Understanding the big picture and the basic principles and practices of sustainable agriculture.)
Keep It – Entrepreneurship, Family Business Dynamics, and Managing Risk. (Planning for the long haul.)
These chapters are followed by appendices with 23 worksheets (also available online from Storey Publishers) and resources.
The arrangement of the book facilitates the learning style/stages the editor recognizes as the real way people learn. This is a book to browse initially, reading the farm profiles to get inspiration, and then return to more methodically learn specific information and skills, using the text and the worksheets. Thus fortified, you’ll be ready to assess what you need to focus on learning next. By clarifying priorities and direction, this approach helps avoid panic and the feeling of being over-whelmed.
In chapter 2 six of the farmers share their experiences about essential equipment and infrastructure, to help new farmers make a shopping list. Here is information about different systems of irrigation (although biased towards methods for Western soils). In Oregon, you can’t farm without Water Rights. For Easterners, it can be hard to understand, as can using glacier water, snow melt or getting only 9” of rain a year. I got lost on the explanation of water drawdown and pressure head requirements. A case of skimming or skipping what you don’t need to know!
In the chapter on Markets and Marketing, six of the farms discuss aspects such as envisioning the market that will meet your needs, overcoming challenges, keeping your focus on values and goals, listening to customers, adapting a CSA model, and evolving marketing strategies over time. This chapter also looks at agritourism, u-pick, farm stands, wholesale and retail markets, and pricing.
Business Management will be vital, sooner or later in your journey. It is a process of continuous learning, continuous improvement. Here is a four-part cycle of planning and setting financial goals; implementing your plan; keeping records; assessing and analyzing your season, then round to more planning. If you want to earn your living from farming, here’s the help you might need. Consider expenses as well as sales, understand depreciation, calculate your profit (your earnings). Remember to include your management overhead time, such as making a new To Do List. Find out if it’s a better use of your time to make hay or buy it. Plan your cash flow month-by-month over the whole year, to make sure there are no avoidable dips into the red. Learn various ways farmers manage cash flow and get loans when needed. Here’s help choosing an accounting system and a record-keeping method. Here are explanations of all the accounting terms that might have left you with a sinking feeling. As Melanie Kuegler of Blue Fox farm says in closing the chapter, “So our highest value is making sure that we’re all taken care of while producing good product for people.”
Chapter 5 on Managing the Whole Farm Ecosystem starts by reviewing the key elements needed to create a successful farm business. This chapter helps you see the whole woodland, not just the trees. Here we look at planning, and contrast that with intervention (what you do when the plan doesn’t work out). For example, in sustainable pest control, the planning might include ways to create healthy crops/livestock to resist pests; making it difficult for pests to settle in and reproduce; boosting populations of beneficial organisms. Intervention includes what you do when pest problems happen. The best interventions include adjusting your plans for the future to avoid that problem. This chapter includes cycles of energy flow, nitrogen, carbon, water, all to help us come up with strong integrated production strategies. Reading the accounts of how various farmers dealt with problems and adjusted their plan contains food for thought for all of us.
The last chapter is guidance on keeping the farm over the long haul. Risk Management is exactly as it sounds. In farming there is always risk. There are so many variables, and some of them we don’t control. We seek the serenity to accept the things we cannot change, courage to change the things we can, and the wisdom to know the difference, as Reinhold Niebuhr’s Serenity prayer puts it. Also the skill to mitigate the impact of things we cannot control but may be able to change a bit. This chapter helps us understand business opportunities, legal requirements and options, and the challenges and rewards of farming. It helps us identify steps to address risk. Several business structures are compared, along with possible interpersonal dynamics. Planning for the long term future includes handing on the farm to the next farmers, whether those are family members or not. Licenses and certifications need to be attended to, and the farmers in this book explain how they tackle those regulations and use them to distinguish the quality of their business and farm products.
The text ends with a short section of challenges and advice from seven of the farms. Staying sane by separating farm work life from non-work life; avoiding burnout by having enough workers that no-one over-does it; taking a day off each week; giving some attention to the health of the farmers as well as the soil, crops and livestock; being really clear about why you are choosing this life; accepting results that are good enough rather than being a perfectionist; distinguishing your farm by doing something superb and/or unusual; paying attention, studying and reading, talking with more experienced farmers; enjoying the sense of satisfaction and pride.
Whole Farm Management is a valuable book to make farming sustainable for the farmers, who can then provide good food for people, and contribute to a better world.