Category: This week in the garden

Direct-sown vegetable crops

 

Young rows of September-sown Eat-All Greens in early October. Direct sown in September. Photo Bridget Aleshire

I wrote a post recently that discussed transplanting, mainly as a way to get earlier crops in spring. Now I’m going to write about direct-sowing. This is the word for putting the seeds directly into the ground outdoors.

As with transplanting, some crops are just not going to thrive if you start too soon: cucumbers, peppers, and even tomatoes, for example. Make sure you can provide conditions that meet the minimum temperature requirements for these tender crops. See my book Sustainable Market Farming, for the details, and The Year-Round Hoophouse for a chart of germination temperatures, telling you how many days each crop will take to emerge at various temperatures. Buy a soil thermometer and push the stem all the way into the soil to measure at a depth of 4” (10 cm) I find it helpful to push the thermometer stem through a larger colorful plastic lid, or stake flag. And install it somewhere safe, where it won’t get stepped on, mowed, or tilled up.

Soil thermometer with colorful background to help us keep it safe,
Pam Dawling

March conditions have become more unreliable, often colder. For example, if the soil at 4” (10cm) deep is 40F (4.4C), you might do better to wait if your chosen crop will take more than 21 days. In cold wet soils, seeds can rot rather than sprout. Write down your sowing date and check the soil for emergence. If nothing has come up when it should have, consider resowing. You could rake or till the whole row or bed and start over, or you could hedge your bets and sow new rows in between the original rows. This might mean ending up with fewer rows, or rows closer to the bed edge than you like, but you will be salvaging an unfortunate situation, so it will be better than a crop failure. If the original rows do come up, you can hoe off the new rows, and it won’t have cost you that much time or money. If the original rows are patchy, hoe them off and keep the new ones.

The pros and cons of transplanting and direct sowing

Before you even venture out there to sow seeds, consider the pros and cons of transplanting versus direct sowing, and when each is most appropriate.You can read these in my post about Garden Planning

Young sweet corn plants after imperfect hoeing.
Photo Pam Dawling

How to sow a row of seeds

Find out how deep the seeds should be: bigger seeds go deeper. If you sow too deep, down where the soil is colder, the seedlings will struggle to reach the surface and may fail. Up to three times the seed diameter, is a concept I’ve often read. Not that you need to measure it!

Drag a triangular hoe (warren hoe) or the corner of a regular hoe, along the ground where you want the plants to grow. If your line is not as straight as you like, fill it in and set out stakes and twine. Either use the shadow of the twine as your mark, or eyeball a constant distance from the twine to the hoe. Remember the depth you need. Fix any deep excavations, or superficial scratches.

Preparing to sow Rainbow Chard.
Photo Pam Dawling

Next open the resealable end of the seed packet and pour some out (not over the gum!) into a small dish or the palm of a dry hand. Keep in mind the plant spacing you are aiming for. Radishes, spinach, chard and beets can easily be seen, and sown at one per inch. Avoid the beginner mistake of tumbling many more times the seed you need in the furrow. It causes more work and weaker plants, because they grow up overcrowded, and you will have to thin them. For small seeds, aim at two or three seeds per inch. Really! It’s hard to get good at this skill, but it is well worth learning.

If you mess up, don’t pick up damp seeds and put them back in the packet. They will damage the dry seeds already in there.

Use the hoe or a rake to draw soil in over the seeds to the previous soil level, not mounded up. Next tamp the soil down over the rows, using a hoe or rake on end. This lets the seeds have good contact with damp soil, so they can get the air and water they need.

Cover with rowcover if needed, or if wanted to speed up growth. With rowcover, you will be biding time while spring warms up. The cold weather crops will not benefit from being overheated. Spinach, lettuce and Asian greens will all bolt if their environment in spring is too warm. Read about factors influencing bolting. You will probably have some warmer weather crops going in and you can move the rowcover on those rows.

Use insect netting if you need to protect your vulnerable seedlings from being gobbled up. You will need to remove the netting once flowers appear, so that the crops can get pollinated. If you have serious trouble with a particular pest, look in seed catalogs for parthenocarpic varieties, ones that set fruit without any pollination.

If it doesn’t rain, water the next day (day 2), then whenever the soil surface is dry. It is better to water deeply less often, than to water lightly each day. Light watering may simply not be enough, and will encourage the seedlings to make shallow roots, which will then die back if you don’t water often enough. Deep watering saves water, as a good depth of soil stays wet, and is protected from evaporation by the surface soil. Some people even go so far as to hoe very shallowly to create a “dust mulch” which prevents warm days wicking the moisture out of the soil. For most of use, this is more of a summer issue than a spring one.

Soaking and pre-sprouting seeds

Some larger seeds benefit from soaking before sowing. Peas and beans can be soaked overnight, but smaller seeds need less soaking. Be careful with beet seeds as they can easily drown and rot if soaked for too long.

Pre-sprouting can help with germination when soil temperatures are too cold or too hot for the crop to germinate in a timely way. In spring, if you presprout, be very careful not to overwater the soil until you see the seedlings emerging. This task is not as exacting as growing bean sprouts to eat. You don’t need to rinse them more than once every few days, if that.

To sow soaked or pre-sprouted seeds, first drain off the free water. If the wet seeds tend to clump together in your fingers, either spread the seeds out on a try or a piece of rowcover or similar, until the problem is solved (an hour?) or else mix the damp seeds with a dry, inert, organic dust, such as oat bran, or uncooked corn grits. Some people use dry sand, but if you have a lot to sow, you will find this quite abrasive to your fingers or to the plastic plate of the mechanical seeder.

Station-Sowing Seeds

If your seeds are expensive, or you don’t have many, or the germination is questionable, you can station sow, rather than sowing in a furrow (drill). Simply press a small divot in the soil at the chosen spacing and put about 3 seeds in the hole. Close the soil over the top. This works well if direct-sowing big crops like okra.

Using a push seeder

EarthWay push seeder.
Photo from EarthWay

If you have long rows, you might use an EarthWay type seeder. These inexpensive push seeders are very quick and easy to use, and come with a set of relatively easily-changed plates with holes for seeds of different sizes. They are lightweight and can be used at a fast walking pace.

Jang push seeder.
Photo Johnny’s Seeds

Market Gardeners will look longingly at the Jang Seeder, which is much more accurate at spacing seeds, and costs an undeniably much larger amount of money. At one time we kept our EarthWay just for carrot sowing (we grew a lot of carrots!), and we used a Planet Junior push seeder for other crops. These are heavy-duty seeders, with plates that are a confounded challenge to change over. In the wrong hands, or on the wrong day, the whole hopper and plate mechanism would fall off. Other people like them for their sturdiness and don’t have the problems I had.

Haraka seeder from Eden Equipment

Growers doing no-till seeding might be interested in the very heavy duty Haraka planter I wrote about last year. It is made in South Africa.

Gap-filling with transplants

A special application of direct-sowing is to prepare for incomplete rows emerging, by having some back-up transplants for gap-filling. We have often done this with our first sweet corn, in case the weather turns cold, or cold rain lands on the plot. Sweet corn can be successfully transplanted up to about 2” (5 cm) tall. We sowed ours in Styrofoam Speedling flats. In cold areas, some growers transplant their whole first planting.

Gap-filling in transplanted crops with station-sowed seeds

Another special application of direct-sowing is to fill gaps in rows of transplanted crops when you have no reserve, backup transplants. This only works for fairly fast-growing crops with long harvest periods. You will need to decide if your seeds will have time to reach harvestable size before the transplanted ones are pulled up.

Year-Round Growing on the Farm and Garden, starting now

At the Organic Growers School Conference, Ira Wallace and I co-presented a half-day workshop (twice!). I uploaded the slides as a pdf on SlideShare.net, and here they are.

Those who start early in “spring” (late winter) might get earlier crops, but when is it worth it?

Some crops are just not going to thrive if you start too soon: cucumbers, peppers, and even tomatoes, for example. Make sure you can provide conditions that meet the minimum temperature requirements for these tender crops. See my book Sustainable Market Farming, for all the details. We used to start these tender crops earlier than we do now. March conditions have become more unreliable, often colder.

If you already have a place to grow protected crops, or you are experienced with rowcover and have plenty on hand, then the signs are good. Crops can be started earlier in a greenhouse or hoophouse (or even on a kitchen windowsill) than you can sow them outdoors. When the plants reach a good size, harden them off and then plant them out in a mild spell, with rowcover for the first couple of weeks. Pay close attention to weather forecasts.

Our greenhouse full of seed flats and sunshine in March.
Photo Twin Oaks Community

“Hardening off” is a process of acclimating your plants to colder, brighter, breezier conditions, so that they won’t suffer when they are transplanted. If you have only a small number of plants, or of flats, you could actually bring them back indoors every night and set them out every morning for 10-14 days. Growers with lots of crops to harden off will make use of a coldframe. Depending on the actual temperature (or the expected night-time low) we might leave our plants uncovered, use rowcover, top the rowcover with transparent lids (“lights”) , and if it’s going to be really cold, quilted covers, weighted down with wood beams if it is the least bit windy.

Our coldframes and greenhouse at Twin Oaks. Photo Twin oaks Community.

After two weeks of hardening off, look for a few days of mild, calm weather to plant them out in the garden. Water the plants well the day before transplanting, and again one hour before transplanting. This allows the cells of the plants to fill up with water, enough to tide them over the period of “transplant shock”.

Even the most skillful of us end up doing some damage to the roots of transplants, and that means the plants have to regrow some lateral roots and root hairs before they can pull in water at the rate they were doing before your ministrations. As you transplant, avoid touching the roots of the plants. Our fingers damage the root hairs.

Okra seedlings in a Winstrip tray in the greenhouse.
Photo Kathryn Simmons

A way to minimize the root damage is to use soil blocks or Winstrip plug flats. These methods are more expensive in time or money than open flats or bare root transplants, but they allow the roots to get “air-pruned” as they grow. When the roots reach the air at the edges of the blocks, or at the vertical slits on the sides of the Winstrip cells, they stop growing, rather than circle around the cell, causing the plant to get root bound. Secondly, these tools work by helping the roots and compost form a coherent block, one that holds together as you pop it into the hole you create in the soil.

Speedling flats are styrofoam flats with tapered cells, and it is possible to slide the plugs out (or gently pull them out) with little damage. Regular cell packs (4-packs, 6-packs etc) can be encouraged to release their transplants by squeezing them at the base of a cell, while holding the pack sideways. Then spread your fingers over the compost around the pant, invert the pack and hopefully the plant and its compost stays as an item, with your fingers either side of the stem.

Transplanting spinach from a Speedling flat. Butter knives are the tool of choice for easing the little wedges out of the tapered cells.
Photo Denny Ray McElya

Hold the plant with one hand by a seed leaf, or if you have to, by the stem. The seed leaves are disposable, stems and roots are not! Hold the plant at the right height, usually with all the stem below the leaves in the ground and all the leaves above ground. Once the plant is in the ground at the right height, hold it there and use the other hand (maybe with a trowel) to push in soil to fill the hole. Firm the soil down quite well, pulling in more soil as needed to leave a level surface. You don’t want the plant to be in a divot, where water can accumulate.

About the degree of firmness: you are aiming to make good contact between the soil and the plant roots, so the roots are not in air pockets, but rather can suck in water from the between soil particles. Don’t firm so hard that you expel the air from the soil and make what feels like concrete the next day. With cabbages, I was taught to firm enough so that if you then grasp a leaf and pull, the leaf tears off, rather than pulling up the whole plant.

Plant for 20-30 minutes, then pause and water in each of the new transplants by hand. Some people will bring a watering can along the row and water each one, one at a time. I prefer to do little batches. At the end of you transplanting session, water the whole row or bed again. try to avoid having piles or dishpans of plants with roots exposed to the air. Definitely don’t take a tea break if you have exposed plants.

Cover with rowcover if needed, or shadecloth if the weather is very bright and sunny. This will just be for a few weeks, helping the plants recover from the transplant shock, and biding time while spring warms up.

If it doesn’t rain, water again the next day (day 2), then on days 4 and 6, then twice a week, then once a week forever after that, until harvest is completed.

A bed of young transplanted lettuce.
Photo Wren Vile

Fruit for the Month of March: Rhubarb

Rhubarb can be harvested earlier in the year than any other fruit.
Photo Kathryn Simmons

We are still in the dormant period for most fruits, but in March, we get to appreciate and enjoy rhubarb! In case you didn’t already know, RHUBARB LEAVES ARE POISONOUS – don’t eat them!

Ruby Red chard. Not rhubarb! Note red veins in the leaves.
Photo Kathryn Simmons

I have a funny story related to this (no one died): One year a novice cook baked us a fine looking pie. She scrupulously cut off every scrap of leaf and put it in the compost bucket. She chopped the stems, added plenty of sugar, and baked the pie. The gardeners among the diners were surprised to get a rhubarb pie so late in the spring. Ah! She had used Ruby chard (sometimes even called Rhubarb chard). The pie was OK, but we were sad not to get to eat he leaves! The non-gardeners ate the pie and found nothing odd about it.

Rhubarb in early spring, not yet ready to harvest.
Photo Kathryn Simmons

Rhubarb is the Focus Fruit for March: Weed, compost around the plants, or where you think the plants are! Mulch if not already done in the fall. Divide & replant if needed.

The information below first appeared in an article I wrote for Growing for Market magazine in October 2009. I have revised it slightly for this post.

This is a good time of year to plan and make preparations for planting new perennial crops. As well as the better known fruits, options include rhubarb, (also known as pie plant), and asparagus. Both are early harvesting crops, so can provide fresh crops to start your CSA season, or enhance your market booth or your offerings for restaurants. Rhubarb can also be used in jam-making, for growers looking for value-added products to extend the market season. Rhubarb is better known among older people, so supplying recipe cards and samples of baked goods or jam may be a good idea to help boost sales. As rhubarb is very tart and rarely eaten raw, you cannot offer raw samples. It needs cooking to bring out the aromatic mellow flavor.

Rhubarb will be in the ground for up to 20 years, so it is important to incorporate it into your field plans after a bit of long-term thinking. This article covers what you need to know to establish the crops, including a look ahead to what you might expect in the future.

Crop Requirements of Rhubarb

Rhubarb appreciates deep soil with high organic matter, and as with all long term crops, it pays to remove perennial weeds before planting. Moderate to high levels of phosphorus and potassium are desirable, and a pH of 6.2-6.8. This is a very easy care crop, with few pests or diseases, requiring little attention.

Rhubarb is a cool climate crop – the north of England is “Rhubarb Central” – the area where rhubarb grows best. I have visited the UK National Rhubarb Collection within Harlow Carr Gardens , near Harrogate in Yorkshire. It’s a collection of different rhubarb varieties, a kind of growing gene bank. Rhubarb does require a winter chill period to break the heat-induced dormancy and start spring growth. Varieties vary in their chill requirements, from about 500 hours at between 28°F (-2°C) and 49°F (9°C). We successfully grow rhubarb in central Virginia, USDA cold hardiness zone 7 and also National Horticultural Society zone 7 for summer temperatures. I was told by a plant nursery in Tennessee that rhubarb would not grow in such a warm place, but our experience says otherwise. Ideal summer temperatures for this crop average around 75°F (24°C). Our summer temperatures include many days above 90°F (32°C). To protect the rhubarb from the heat, we planted it in a single north-south row, directly west of our asparagus and east of our grapevines. In summer it is shaded on both sides. Choose a microclimate to protect from extreme temperatures, and from drying out. It is hardy down to –20°F (-29°C). Early season open sun exposure is valuable.

Rhubarb row between grape rows, which provide shade in summer. Photo Bridget Aleshire.

Ensure a good regular supply of water from spring when growth starts, until fall frosts. On the other hand, avoid water-logged sites, as Crown Rot is one of the few diseases rhubarb can suffer from. Very sandy soils aren’t good for rhubarb, unless you can make heavy additions of organic matter. To test drainage at a potential site, dig a 12” (30 cm) hole, fill with water. If the water has all percolated within 3 hours the site is suitable.

Choosing Rhubarb Varieties and Buying Plants

Although rhubarb can be grown from seed, it is much more usually grown from “crowns” (young plants), or from pieces of crowns divided from established plants. Plants started from seed will be two years old before harvest can start. Our plants at Twin Oaks are of unknown parentage, having been divided and moved around the farm a few times. Many people don’t even realize that rhubarb has distinct varieties, and many nurseries only offer one or two. Growers may wish to select either red or green stalks (green can be more flavorful), yield, disease resistance or winter chilling requirement. Try to get recommendations from other local growers, or buy several and see which does best. Here’s some information I’ve found, although there may be duplication of names for the same variety:

  • Macdonald: pinky-red, thin tender, upright stalks, some resistance to crown rot.
  • Victoria: green tall stalks, good vigor, tart flavor, makes many seed stalks.
  • Tilden: Good red color, thick stalks.
  • Valentine: Good red color, medium vigor, few seed stalks.
  • Crimson: Thick red stalks.
  • Canada Red: for cooler regions. Red stalks, high in sugars.
  • Red Cherry: for low winter chill areas. Grown in California.
  • Allport Giant rhubarb (found growing in woodland in Chenango County, NY), now for sale as seeds.
Red and green stems of rhubarb.
Photo Small Farm Central

Propagation of Rhubarb

Once you have some established rhubarb it is very easy to propagate and have more. The roots of rhubarb become enormous, and even small broken pieces will grow. To divide the crowns, use a sharp shovel or spade to chop through an unearthed crown, creating pieces with 2 or 3 buds on each. This can be done very early in the spring, before growth has started, or late in the fall. If fall is the recommended time for planting other fruits in your area, it will also work as a time for dividing rhubarb. After dividing, let the cut surfaces air dry for a day or two before replanting.

It is generally recommended to renovate rhubarb plantings every 5-10 years, by digging up and dividing the roots. This gives the opportunity to move or to increase the planting. If your stalks have become thin, brittle and hollow, it’s time to divide and renovate your planting.

Planting Rhubarb

Plant in very early spring (or late fall). If you buy crowns and cannot plant them when they arrive, store them in a refrigerator, and check to prevent mold growing during storage. After preparing your site and removing perennial weeds, incorporate about 15 tons of compost per acre (34 metric ton per hectare). On a smaller scale, this translates to one or two shovelfuls of compost per plant. Crowns should be planted 2-3 ft (0.6-1 m) apart, with the bud about an inch (2.5 cm) below the soil surface. Make trenches or holes 6” (15 cm) deep. Fill in the holes or trenches, pack firmly (except directly over the bud), and water well. For multiple rows, space the rows 3-4ft (1 m or so) apart. Rhubarb is a large plant and will easily use this amount of space. To combat over-wet soils, use raised beds. Organic mulch will help prevent weeds and keep the soil cool and moist.  

Rhubarb Growth

Small March rhubarb plants with wood chip mulch.
Photo Pam Dawling

Rhubarb grows actively in the spring, and then in most climates, goes dormant for the summer. Once fall frosts arrive, the leaves and stems will die back to the ground and you can do the annual maintenance.

Give an annual application of compost in the fall when the plant goes dormant, and mulch around the plants with straw or spoiled hay. In early spring come back to your plants, weed, and add more mulch and perhaps more compost if needed as soon as you see the big pink buds emerging from the soil. Provide 1-2” (0.5-1 cm) of water per week.

The warmer your climate, the more flower stalks you will see. Unlike the squarish leaf stalks, flower stalks are round. They quickly grow tall, above the leaves, and have big buds at the top. For maximum rhubarb yield, remove these flower stems as soon as you see them, by cutting them low down, or at least by cutting off the flower buds as you go by. We harvest stalks twice a week in April and May, and cut the flower stems out at the same time.

If your rhubarb flowers, cut off the flower stems, preferably before the buds open, to keep the energy for the stalks.
Photo Pam Dawling

In the Rhubarb triangle in Yorkshire, England, there are farms with dark forcing sheds, where pale pink rhubarb grows. It is harvested by candlelight. Click the link for the audio slideshow.

Rhubarb Harvest

Harvesting rhubarb. Photo Bridget Aleshire

Rhubarb emerges from hibernation once temperatures have reached the upper 40°F (5°C) range for several weeks. Do not harvest stalks the first year after planting, as it is important to help the plant get well established.

Most people harvest by grasping a thick stem near the base, and twisting and pulling. We like to pull 1/3 of the stalks available and leave at least 2/3 of them growing, but with big plants you can remove half of the stalks, provided you leave at least 10 stalks per plant. I believe it is possible to cut all the stems at ground level, if you have a big commercial planting and need a fast harvesting technique. This may only apply to those growing rhubarb as an annual, setting new plants each year.

The leaves (and any frosted stalks) of rhubarb are poisonous, as noted above. This is due to the presence of oxalic acid, so play it safe and cut the leaves off in the field, bringing only the stalks to the shed. We like to stand the stalks upright in buckets and add an inch (2.5 cm) of water to keep them crisp.

As well as the 6-8 weeks of spring harvest, it is also possible to take one or two harvests in September, in most regions. Some people “force” rhubarb for an earlier spring yield, using rowcovers or field houses, or digging up the roots in late fall and replanting them in a heated greenhouse. Forced plants can be harvested twice a week for 4-6 weeks, but then they are fairly exhausted.

A respectable yield is 2-3 pounds (1-1.5 k) of stalks per mature plant per year, or 15 tons per acre (34 metric tons per hectare).

Rhubarb recipes

It’s not just pies and crumbles (similar to cobblers). I recently saw a recipe for mackerel with rhubarb. Roasted rhubarb, topped with mackerel fillets, broiled (that’s “Grilled” in the UK), and served with watercress. Back in the dessert realm there are cold summer dishes like rhubarb fool, a kind of fluffy soufflé.

More Rhubarb Information

Iowa Extension has a free 2-page online publication Rhubarb in the Home Garden

University of Minnesota Extension has a web page with a lot of pop-out info sections: Growing Rhubarb in Home Gardens

GrowVeg has a YouTube Rhubarb from Planting to Harvest

The wonderful website, The Rhubarb Compendium includes planting information, propagation, history, lots of recipes, photos, everything you need to know, in a dozen Informational pages.

Virginia Tech Extension Service has a good Specialty Crop Profile on Rhubarb by Tony Bratsch, covering large commercial production as well as information for small growers.

Some other university extension sites also have good information on rhubarb, particularly Oregon State, Kansas State, Purdue and the University of Kentucky.

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Special Topic for March: Nutrition facts on rhubarb.

Sources include: USDA

26 Calories  –

Nutrient Amount(g) DV(%)
Total Fat 0.2 g 0%
Cholesterol 0 mg 0%
Sodium 5 mg 0%
Potassium 351 mg 10%
Total Carbohydrate 6 g 2%
Protein 1.1 g 2%

 

Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.

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Other small fruits still available in March

Dried and frozen fruits, jams, jellies, chutneys, other preserves, or even stored apples and pears are all we are likely to have, apart from buying imports. Remember that vegetables are at least as nutritious as fruit, but simply have fewer sugars. The vitamin C content of green leafy vegetables is as good as oranges. Even potatoes have a fair amount of vitamin C, as Carol Deppe points out in a very interesting article The 20 Potato a Day Diet versus the Nearly All Potato Winter  about the nutritional and gastronomic wonders of potatoes.  It will inspire you to grow and eat more potatoes! (if you can find it. I can’t now.) Try https://www.resilience.org/resilience-author/carol-deppe/

The vitamin C is concentrated just under the skin, so hopefully you have grown organic potatoes and will eat the skins too.

Crates of potatoes stored in our root cellar.
Photo Nina Gentle

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Other fruit care in March in the mid-Atlantic

Complete any weeding, fertilizing, mulching, and planting new plants early in March! Mow aisles (a regular task from now on.)

Blueberries: Plant new bushes now, before buds break. Weed, and restore mulch if it is thin. Set up irrigation – we’ve often been surprised how early in the year we need to start irrigating.

Summer-fruiting raspberries: Mulch, water. Weed shallowly. Set up ropes or wires to hold the canes in check.

Fall raspberries: Weed and water all raspberries. Plant new canes if needed, keep the roots damp during planting. Once the beds are all prepared, go ahead and set T-posts and ropes or wires to corral the newly emerging canes. We like to use T-pots so we can remove them at the end of the season and mow right over the beds. Fall raspberries start from scratch growing new canes each year. It’s a great help with weeding!

A frosted strawberry flower with a black center.
Photo Kathryn Simmons

Strawberries: Weed this month, before the winter annual weeds seed all over the place. Water new beds if they need it. Get rowcover out once you see flowers. That’s not till April here, but if you are in a warmer climate you need to know to cover any flowers on frosty nights. The leaves will be fine, so if your rowcover is skimpy, it’s OK if leaves are exposed for the night.  Keep deer off (electric fence?) Set up drip irrigation and water twice a week from now till November, unless it rains enough. Top up wood chip path mulch. Fill any gaps using runners.

Grapes: Mow if needed. Water if there is a spring drought. Weed, top up mulch if needed. This is the last chance this year to plant new vines. Prune them after planting, and tie them to a sturdy cane or the low wire of the trellis. If using the Geneva Double Curtain method, note that vines are trained to alternate sides of the bottom wire and then to alternate sides of top wires, where they will have space to spread.

Random fruits: Depending on your climate, you could still plant new fruit bushes and canes, and there may still be pruning to take care of. This is a good time to repair or replace broken support frameworks.

More on Blueberries; Crop Planning Slideshow

Admiring a cluster of blueberries.
Credit Marilyn Rayne Squier

More Resources on Blueberries

Since my post on Fruit for the Month of February, I have found some more really good resources on blueberries

Blueberries are easy to grow if conditions are right. They are a popular choice with organic growers, because they don’t need any pesticides to produce a good crop. They do, however, need annual pruning to be sure of a high quality crop. Pruning also keeps the bushes at a height easy to harvest from. Pruning is done during the dormant season, usually between December-early March in the Piedmont.

Some people are reluctant to prune because it does remove some of the flower buds and reduces berry production for that year, but if pruning is not carried out, berries become smaller each year and the health of the bushes declines. Pruning is an investment in the long-term success of your plants!

The Growing Small Farms website links to many how-to videos and fact sheets, with diagrams and photos. There are excellent resources on pruning and blueberry production in general. Everything you need to know about pruning blueberry bushes!

Side-by-side comparison of blueberry bushes before and after pruning. Slide by Bill Cline
Read more at: https://growingsmallfarms.ces.ncsu.edu/2023/01/february-is-a-great-time-to-prune-blueberries/

Another good resource is this article in the Agricultural Research Service newsletter

More People are Getting the ‘Blues’

By Scott Elliott, ARS Office of Communications.

Here is some recent information on blueberry research. New varieties, and a disease to watch out for.

Researchers at the Horticultural Crops Production and Genetic Improvement Research (HPCGIR) Unit in Corvallis, Oregon, are developing new cultivars of not just blueberries, but also blackberries, red raspberries, black raspberries, and strawberries to meet the particular needs of growers in the Pacific Northwest. Also useful to those in other areas.

“We focus on improving the shelf life of fruit so that it reaches consumers with consistently better texture and flavor,” said Claire Luby, plant geneticist with HCPGIR. Perhaps a large challenge for Luby and her colleagues is developing a cultivar that is resistant to a disease known to be a scourge of the berry: blueberry shock virus.

Blighted flower clusters due to blueberry shock virus infection. https://www.ncipmc.org/projects/pest-alerts/blueberry-shock-virus-bromoviridae-harvirus/

Click to download a PDF version of the Blueberry Shock Virus publication.

“We’re studying diverse blueberry plants to understand the genetic basis for blueberry shock virus, which can significantly impact yields for farmers,” she said. “Our hope is to use the insights from this project to develop new cultivars that are resistant, or at least more tolerant to, the disease.” Blueberry shock virus has caused annual crop losses of 34-90% in the Pacific Northwest.

Researchers combine traditional plant breeding with genomics to create their disease-resistant cultivars. The traditional technique (used in one form or another by people trying to improve agricultural crops for millennia) is to take pollen from one plant and use it to pollinate a different plant with complementary characteristics. They study the progeny of these crosses, looking for new characteristics that meet the goals of the breeding programs. Traditional blueberry breeding can take more than 20 years from the time an initial cross is made to when a consumer might eat from a resulting cultivar.

“We try to improve the accuracy and speed of the plant breeding process,” Luby explained. “We are now able to obtain a lot more genetic information about the plants and we can use that information to potentially predict whether an offspring of a given cross might have the characteristics we are looking for before we plant it out in the field. This is important because it can increase the speed of the plant breeding process.”

“Our goals are to develop blueberries that require fewer chemical inputs to fight disease, which can be better for both the environment and for growers’ bottom lines,” Luby said.
 The Agricultural Research Service is the U.S. Department of Agriculture’s chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in U.S. agricultural research results in $20 of economic impact.

Crop Planning for Sustainable Vegetable Production

Twin Oaks Garden Colored Spots Plan for crop planning

At the in-person Pasa Sustainable Agriculture Conference, I gave two presentations. I also sent a recorded workshop for their virtual conference in January. That one was Feeding the Soil. I’ve just scoured through all 8 pages on my website that check the category “Slideshows”. I found Feeding the Soil twice.

My Alliums Year Round presentation is new this year and I posted the handout after my presentation at VABF. Pasa had shorter workshops, so I pruned the slideshow, but left the handout with the “bonus material”.

My other presentation at Pasa was Crop Planning for Sustainable Vegetable Production. That is one of the very first topics I tackled when I started out as a speaker, so the three versions on this website span the past ten years. 2014, 2016, 2019. Here is the 90 minute 2023 version and ts handout:

Crop Planning 2023 90 min presentation
 Crop Planning 6 pg Handout 2023

 

Fruit for the Month: February

Young blueberry plant in snow. Photo Bridget Aleshire

We are in the dormant period for most fruits, with really none to harvest, although this is a good month to eat stored and preserved fruit.

Depending on your climate, you could start to plant new fruit bushes and canes, and whether you do that or not, there is plenty to prune and care for.

Blueberries are the Focus Fruit for February

Harvest blueberries in June in the mid-Atlantic. Photo Small Farm Central

Blueberries were also the Focus Fruit for June, when I wrote about harvesting them, and about the differences between Rabbiteyes, Northern Highbush and Southern Highbush types, and about planting. If you are about to buy plants, let me remind you that we have bought good plants from Finch Blueberry Nursery in Bailey, North Carolina, as well as from a more local source in SW Virginia (now retired). If you only want a few plants, buy potted blueberry plants locally. Otherwise, order bareroot plants shipped to you. In Virginia Edible Landscaping offers a wide choice.

Growing Blueberries

Blueberry bush with buds in March. Photo Pam Dawling

It used to be a tradition here, that the first garden shift of the year, in late January or early February, after the winter break, was spent pruning blueberries. During December and January, only a few people were working in the gardens, harvesting hardy crops, and tending to the hoophouse and greenhouse. Once the rest of the crew returned, we cleaned, sharpened and oiled the pruners, and set to work.

We have two patches of blueberries, both Highbush, despite being in a climate where you might expect Rabbiteyes to do better. The older patch has four rows of eleven bushes, which have been growing there since before 2007. Mostly we don’t know the names of these varieties. We have replanted to fill gaps over the years, and each spring we have logged how they are doing, whether they are early or late, productive or not, small or large berries, delicious or OK.

Young blueberry plant protected for winter with mesh.
Photo Kathryn Simmons

The newer patch was planted in November 2007, with 4 plants each of five varieties, planted in two rows in the order we expected them to ripen: first Duke, then Spartan, Bluecrop, Chandler and Aurora. The Duke variety has by far been the best, both productive and tasty. The Spartan early on declared itself to not be suited to our location. We have digital records of this patch from 2016-2019. Probably we have paper records from 2007-2015. At the last count, we had 4 Duke, 1 Spartan, 6 Bluecrop, 3 Chandler and 6 Aurora. We have propagated Duke to replace casualties in the old patch.

If you are looking for good varieties for central Virginia, here’s what I gleaned from our notes:

  • Duke: Good strong, productive plants
  • Spartan: Not right for this area, didn’t thrive
  • Bluecrop: Did well initially, started to die out by 2016
  • Chandler: maybe earlier than Bluecrop, large berries.
  • Aurora: Very late, large berries, so-so flavor.

Blueberry Plan/Annual Calendar

Late January/February in a mild spell: Pruning (See Special Topic below)

Late January/early February:

  1. Weed
  2. Add soil amendments such as sulfur, if soil test indicates a need.
  3. Add compost
  4. Renew mulch: Rake remains of old mulch aside first. Double cardboard, then replace old woodchips and top up to 3” with new woodchips or sawdust. The new patch had landscape fabric underneath at first, but that was removed, so it now needs double cardboard and new chips, just like the old patch.
  5. Plant new bushes to replace casualties.
  6. Repair fencing if needed.

Early Spring (April? March if there’s a drought):

Check irrigation and start irrigating twice a week. Weed.

Late Spring (May):

  1. Old patch – tackle Nut Sedge by several repeated cultivations with rakes or hoes when nut sedge is 3-4” tall.
  2. When flowers are setting fruit, install the roof netting.
Blueberry netting on hoops.
Photo Bridget Aleshire

June:

Harvest.

Summer (August):

Weed. After harvest, remove and store the roof netting, check perimeter fencing.

Fall (September/October/November):

Prepare new area if needed. Plant new bushes in November (or wait till Feb)

Weed, spread compost, mulch, take soil tests.

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Pruning young blueberries.
Photo Lori Katz

Special Topic for February: Prune Blueberries

 

Late January/February in a mild spell:

1-2 year old bushes: remove all flower buds (the plump round ones). Remove tiny weak shoots and leave a sturdy bush.

General, all ages: Remove all dead, diseased, damaged and dying wood.

  1. Decide whether to propagate. To layer a low-lying branch, scrape the bark on the underside, pin it down to the ground with a 6” wire staple, weight the pin down, and flag it. Layering has been much more successful for us, but it is possible to make hardwood cuttings, with 3-5 buds hardwood sticks (not flowering tips), and root these.
  2. Remove cross-overs, low-lying branches, branches heading for the center of the bush, branches hitting the roof of the netting.
  3. For young bushes, up to 4-years old, that’s all the pruning you do. Aim to leave a sturdy, healthy bush. Focus on removing spindly stuff. For older bushes, continue with step 5 onwards.
  4. Count the thick old trunks bigger than 1.5” diameter, divide by 5 and saw out this many, at ground level, (unless it would leave fewer than 6). Choose the oldest, scaliest, darkest ones for removal.
  5. Remove any spindly growth, tangled clusters.
  6. Remove a portion of the younger stems, to leave a balance. The ideal is something like 20% less than 1” diameter, 60% 1-2”, 20% larger than 2” diameter.
  7. Bear in mind that the fruit buds are plump – don’t remove more than 50% in total, but don’t fret about removing up to this number. If the bush carries too much fruit, berries will be small, branches break and bush reserves get depleted.
Layering a blueberry branch to propagate a new bush.
Photo Kathryn Simmons

Here’s information from Pruning Blueberries in Small Fruit in the Home Garden from Virginia Extension

“Until the end of the third growing season, pruning consists mainly of the removal of low spreading canes, and dead and broken branches. As the bushes come into bearing, regular annual pruning will be necessary. This may be done any time from leaf fall until before growth begins in the spring. A mature blueberry plant should produce three to five new canes per year.

During pruning, clean out old, dead wood, and keep the three best 1-year-old canes. Locate the oldest canes and prune out one of every six existing canes; cut as close to the ground as possible. A mature blueberry bush should have 10 to 15 canes: two to three canes each of 1-, 2-, 3-, 4-, and 5-year-old canes (fig. 3).”

Figure 3

Figure 3. Left, unpruned blueberry plant. Right, after
pruning, a mature blueberry bush should have 10 to 15
canes.

Blueberry flowers.
Photo Kathryn Simmons

More Blueberry Resources:

  1. Blueberry Production Guide (NRAES-55) 1992, Pritts and Hancock
  2. NRAES-055_ePub.epub   (10.54Mb)
  3. Cornell 2022 Organic Production and IPM Guide for Blueberries, Carroll and Pritts
  4. Strik, B.C., D. Bryla, and D.M. Sullivan. 2010. Organic Blueberry Production Research Project. eOrganic article.

Other small fruits still available in February

Dried and frozen fruits, jams, jellies, chutneys, other preserves, or even stored apples and pears come into their own this month. Pawpaws can be eaten frozen like ice cream. Don’t eat the skins, and don’t eat cooked pawpaws, or you may get Tummy Trouble.

Wintergreen berries persist on the plants in the wild all winter, but don’t taste good at the end of the winter, though, so do a taste-test before harvesting lots. If you are allergic to aspirin, avoid wintergreen because all parts of the plant contain methyl salicylate, an aspirin-like compound.

Other fruit care in February in the mid-Atlantic

Summer-fruiting raspberries: cut out old canes (last year’s fruiting canes), Thin new canes (that didn’t bear fruit last year) to 6 per foot of row (ie at least 2” apart). Weed. Water.

Fall raspberries: Prepare future new beds. Plant new canes with compost. Mulch around them. Set new T-posts for trellising once the new canes start growing. In existing beds, cut all last year’s canes to the ground and dig up canes from aisles. Weed, compost, mulch.

Don’t let this happen to you: A frosted strawberry flower with a black center.
Photo Kathryn Simmons

Strawberries: Remove any winter hoops, polypropylene rowcover or slitted plastic and clips. Plant a new replacement bed if not done in August or September. Restore paths if needed. Weed. Compost if none in August. You could keep the rowcover handy for the flowering period, to cover in frosty weather. Or you could pack it away while you tidy up the beds and paths, and get it out again once you see flowers.

Rhubarb: Weed, compost around the plants, or where you think the plants are! Mulch if not already done in the fall

Grapes: Weed. Spread compost. Install irrigation. Prune: 50 buds per vine. Prepare sites for new vines.

 

Fruit for the Month: January (Grapes)

Two rows of grapes in spring after weeding, fertilizing and mulching. Photo Kathryn Simmons

We are in the dormant period for most fruits, meaning few-to-none to harvest, none to plant, but plenty to prune and care for, and new plantings to plan for the new season.

Grapes are the focus fruit for January

Frosty grape vines.
Bridget Aleshire

Grapes also featured as the focus fruit in August. Then I said:

“We grow Labrusca grapes, mainly Concord, with a few Allred, with a selection of other varieties that we are trialing, including the Planets (Jupiter, Mars, Neptune, Venus) and Edelweiss, Fredonia, Marquis, Niagara, Reliance, Sheridan, Steuben, Vanessa. All these are suitable for juice, jam and jelly. Fredonia, Marquis, Mars, Niagara, Reliance, Steuben, Vanessa and Venus are dessert quality, but mostly they have thick skins, big seeds, and a sour taste. Some of these varieties are susceptible to Downy Mildew, Powdery Mildew and/or Black Rot, and I wouldn’t buy those again. Likewise, I would not buy grafted vines, such as the Cynthiana and Niagara, as we are not good at remembering to cover and uncover the graft unions when the seasons change.”

In that post I talk about planting and trellising (Geneva Double Curtain)

Trellis arm construction for Geneva Double Curtain grape support system

In January, we check and repair the drip irrigation, update maps and logs. We kept good records for a number of years after we planted the new trial varieties (2008, I think).

Our grape drip irrigation tubing, showing an emitter and a clip holding the tubing to the (rusty) wire.
Pam Dawling

It is possible to take dormant wood cuttings, 6-9” (15-23cm) long, cut at the top 1” (2.5cm) above a bud at a slope. Heel them in, and label clearly.

Weed the rows, particularly around new vines, as soon as weeds start to grow. Finish cardboard and sawdust mulch if not done in December.

Grape planting and pruning doesn’t happen here till early March. Avoid pruning grapes in a spell of cold weather, as it can cause vines to die back from the pruning cuts. Vines pruned after the buds start to swell will leaf out a little later, and may avoid late frosts. If the first set of flower buds get frosted, the grapes will produce a second set. Harvest will then be about three weeks later than it might have been.

A grape vine budding out in spring.
Kathryn Simmons

If your grape rows have developed gaps, layering branches of neighboring vines is a very effective gap-filling method. Lay a vine lateral with several buds down into a 5” (12cm) deep trench. Cover the vine with 3” (7.5cm) of soil, leaving the tip above the surface. When new growth starts to appear, fill the trench and pack firmly. Separate the plants the following fall. Layering can also be done in the fall.

Special Topic for January:     Grape Varieties for Organic Production in the Southeast

GRAPE VARIETIES

The Cornell  2022 Organic Production and IPM Guide for Grapes 2022-org-grapes-NYSIPM.pdf  is a great resource. It covers site selection, variety selection, nutrient requirements, soil health, pre-planting and under-vine cover crops, integrated pest management, and more in its 90 pages. Be aware that it is written with the Northeast in mind. For a more general approach, see Grapes: Organic Production. ATTRA, Rex Dufour.

Other small fruits still available in January

You may have dried and frozen fruits, jams, jellies, chutneys, other preserves, or even stored apples and pears. Pawpaws can be eaten frozen like ice cream. Don’t eat the skins, and don’t eat cooked pawpaws.

I wrote about fruit storage in December.

Wintergreen berries persist on the plants in the wild all winter, and become sweeter after some cold weather. They don’t taste good at the end of the winter, though, so harvest while they are good eating. If you are allergic to aspirin, avoid wintergreen because all parts of the plant contain methyl salicylate, an aspirin-like compound.

Medlars are a peculiar ancient old-world fruit, with not much modern-day interest. The fruits are not edible until “bletted” by a hard frost or by waiting beyond normal ripeness, when they get very close to rotting. The small trees have beautiful spring blossoms, and if you don’t harvest the fruit, they remain on the twigs during the winter, giving added interest then. They can also be eaten frozen during winter walks through the orchard.

Other fruit care in January in the mid-Atlantic

Summer-fruiting raspberries: Weed and mulch. Give compost now or in February.

Drip irrigation works well for raspberries, such as these fall-fruiting Carolines. Photo Kathryn Simmons

Fall raspberries: cut canes to ground and dig up canes from aisles. Weed.

Strawberry beds in their second year. Rowcover at the ready for frosty nights during flowering. Photo Kathryn Simmons

Strawberries: In colder areas, you may have covered them with hoops, polypropylene rowcover or slitted plastic and clips. Weight down the edges with sticks, rocks or sandbags.

Propagate blueberries by layering a low branch, as you see here with Chandler variety. Photo Kathryn Simmons

Blueberries: Weed and spread compost around the bushes, out to the dripline.  Give soil amendments in line with soil test results – blueberries thrive on acid soil, so you may need to add sulfur pellets.  After adding all amendments, renew cardboard and sawdust/other mulch if not done in fall. In late January, we prune and propagate by layering, which is the easiest way to successfully propagate blueberries.

Rhubarb in early spring, not yet ready to harvest.
Photo Kathryn Simmons

Rhubarb: Weed, compost around the plants, or where you think the plants are! Mulch if not already done in the fall

Read books: See my reviews of Levy and Serrano Cold-hardy fruit and nuts, and Blake Cothron’s Berry Grower. The RHS recommends Harvesting and storing garden fruit by Raymond Bush (Faber and Faber 1947, ISBN 54053000473672). Plan more fruit and place orders for delivery after the coldest part of winter. In milder areas, start planting at the end of January

 

Conference Season, cold damage update, potato yield error in my book

Conference Season

It’s busy season for conferences, so I’ll tell you about the next two I’m speaking at. You can go to my Events page to see what’s further ahead.

This weekend (January 6-8 (Fri-Sun), 2023) is the Virginia Association for Biological Farming at the Hotel Roanoke and Conference Center

VABF 2023 Conference banner

Virginia Association for Biological Farming

23rd annual Virginia Biological Farming Conference

VABF Conference INFO Home Page

The 23rd annual Virginia Biological Farming Conference is Virginia’s premier organic and sustainable agricultural conference! The Conference brings together farmers, gardeners, eaters, educators and advocates of biological and organic farming and gardening. The Conference will be held in person January 6-8, 2023 at The Hotel Roanoke and Conference Center.

The three-day Conference includes:  Full and Half Day Pre-Conference intensive workshops, 50+ sessions and workshops, presentations and panel discussions, 40+ tradeshow exhibitors, locally sourced farm meals and book signings. The Conference features a Silent Auction and networking opportunities including regional networking meetings, and the Taste of Virginia Expo & Social! 

Keynote Speakers

Dr. Elaine Ingham, Soil Food Web School

Leah Penniman, Founding Co-director Soul Fire Farm

I will be presenting a half-day workshop 8am-noon on Friday Jan 6, on Year-Round Hoophouse Vegetables

90 minute workshop Sunday January 8, 8.30 am – 10 am Alliums Year Round
90 minute workshop Sunday January 8, 10.30 am – noon, Asian Greens in the Winter Hoophouse

See the 2023 Session Summaries

Taste of Virginia Expo and Market & Social

Included in the Conference Registration and free and open to the public is the Taste of Virginia Expo & Market on Saturday, January 7, 2 – 9 PM in the Crystal Ballroom at Hotel Roanoke. Featuring sampling and sales of Virginia-crafted foods, local libations, handicrafts, and herbals. Complete the evening with music, dancing, and socializing from 8-10 PM.

Locally Sourced Meals

VABF and LEAP Local Food Hub are working together to procure the majority of our Conference food from local member farms. We look forward to supporting our member farms and enjoying delicious, fresh, local food from the farms below! All Conference Registrations include lunch and dinner on Saturday, lunch on Sunday and morning coffee and tea.

VABF logo

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NOFA-Mass Annual Winter Conference, January 12-14, 2023

Northeast Organic Farming Association, Massachusetts Chapter.

The Conference will be held at Worcester State University on Saturday January 14 and online Sunday January 15. We encourage you to make the most of the range of possibilities – i.e. tastings in person, international discussions over Zoom, tool modifications, storytelling. Creativity is welcome!

An organic lunch on Saturday is sandwiched by over 40 educational workshops for a full day of learning and socializing.

This is a valuable opportunity for farmers, gardeners, homesteaders, educators, and environmentalists to share resources and ideas to grow our vibrant organic community. We are excited to come together around this winter’s theme, “Cooperative Foodways: Building Our Future Together.”

The conference hosts 40+ workshops and draws hundreds of attendees from throughout the Northeast.

I will be giving a workshop on Crop Planning for Sustainable Vegetable Production

———————————————-

Cold damage update

Bright Lights chard with cold-damaged stems.
Dec 27.
Pam Dawling

I reported very little damage to our hoophouse crops last week when it was 2F (-17C) outdoors. Since then, no plants keeled over, but some leaves are showing tan patches of dead cells, either where the leaves touched the rowcover. or where they were not properly covered. So, we have lost some leaves of senposai, a few of spinach, some on the yarrow we planted for beneficial insects. But, overall, I’m extremely happy with the good condition of our crops.

—————————————————-

Mistake about potato yields

Sorting potatoes two weeks after harvest to remove problem potatoes before rot spreads.
Photo Wren Vile

Yes made a mistake back in 2012, when I wrote Sustainable Market Farming, which I hope has been corrected in reprints since I was first notified of this in August 2019. If you have an older edition of my book, it might still have the error. In yield numbers on page 376, it says about potatoes, “Yields are likely to be 150 lbs/ac (168 kg/ha); 200 lbs/ac (224 kg/ha) is a good yield”.

I posted on my blog about this: https://www.sustainablemarketfarming.com/2019/08/20/ice-for-lettuce-seed-mistake-in-my-book-fall-sowings/

“Yes, my mistake indeed! On page 45, I have the (better!) info that potatoes can yield at least 110 pounds/100 feet, or 49.9 kg/30m. I think I probably meant to write on page 376, that a low yield could be 150 pounds/100ft, which is equivalent to 11 tons/acre. In the metric system, that’s 223 kg/100m, or 24.4 tons/ha. Other sources suggest average yields could be almost twice this. And good yields, even 4 times the low numbers.

So it should say

“Yields are likely to be 11 tons/ac (24.4 tons/ha); 22 tons/ac (48.8 tons/ha) is a good yield”

That’s US tons of 2000 pounds, metric tons of 1000 kg. Or for a smaller scale, probably closer to what most of us are growing,

“Yields are likely to be 150 lbs/100ft (223 kg/100m); 200 lbs/100 ft (300 kg/100m) is a good yield”

I hope I’ve got all the conversions right.

How cold can leafy greens and salad crops survive?

Our hoophouse beds after the nights at 2F (-17C) and 8F (-13C). Looking amazing! Pam Dawling

We were luckier with the weather than many people over the weekend (12/23-12/26/2022). And so were our vegetable crops. On Friday 12/23 we prepared for a suddenly very cold night. It was very windy as we battled to stop the hoophouse windows from blowing open. We finally got some shims, a hammer and a stepladder, and wedged them closed. They stayed that way until Tuesday 12/27. We were fortunate in getting no precipitation (I hate ice!) and no power outage.

Pool noodles repurposed as draft excluders.
Pam Dawling

We fortified the doors with our rock collecting buckets, and prevented most of the under-door drafts with our pool noodle draft excluders. They have a rope running through them, which is hooked onto small cup-hooks on the door frame. We repurposed noodles that had been used as props at a party or some other kind of event. They had been covered in tube socks and had glued-on googly eyes.

Rolls of rowcover at the ready in our hoophouse.
Pam Dawling

It was a bit unnerving being in the hoophouse as it creaked and groaned in the wind. In the winter we keep rolls of rowcover ready for any night we think will be below 8F (-13C). We unrolled the rowcovers by lunchtime and laid tools on the ends nearest the doors. I was worried that if we lost power, and therefore the inflation, it would get very cold indeed in the hoophouse.

The DIY manometer in our hoophouse. (the background lines have faded). Pam Dawling

Since we last changed the plastic we haven’t managed to get the recommended 1/3” (8.5mm) pressure difference in the “bubble” between the plastic layers, compared to our normal air pressure. Mostly we don’t even get ¼” (6.5mm). The “bubble” provides thermal insulation as well as physical strength against snow or ice buildup, and strong winds.

It got down to 2F (-17C) outdoors Friday night, and Saturday didn’t warm up much. I don’t actually know what the night temperature was in the hoophouse as our recorded low temperatures don’t make sense: 14F (-10C) for four consecutive nights (Fri to Mon). I suspect we didn’t reset the thermometer correctly. Usually the hoophouse can hold 8 F (4.5 C) degrees warmer than outdoors, but not 12 F (7 C). It looks like it did, perhaps because we didn’t open it all day!

Soil thermometer in our hoophouse on 27 December 2022.
Pam Dawling

The soil is still nice and warm in there: 59F (15C). That really helps. The rowcovers are usually removed in the daytime, either pulled aside if we expect to need them again the next night, or rolled up out of the way. Most of the time they stay rolled up at the east end of the hoophouse. We appreciate not needing to deal with rowcovers most of the time! On Saturday 24th, the temperature maximum for the day outdoors was 24F (-4.5C), and we kept the rowcovers in place over the crops. On Sunday the high outdoors was 28F (-2C) so we pulled the rowcovers aside until the night. On Monday 26th the night-time forecast was benign enough that we rolled the rowcovers up. And now we get a milder spell.

Hakurei turnips with frozen yellow leaves where they touched the plastic (rowcover protected the plants). Pam Dawling

How did the crops fare? It’s not always obvious at first if a crop has been killed by cold or not, But I can now say with confidence that nothing died. The edge beds are always the coldest. The south edge bed had Hakurei turnips, delicious and notoriously the least cold-hardy turnip variety. Most of the globe of the turnip sits on the surface of the soil. You can see in the photo that some of the leaves, the ones right by the wall plastic, have been killed and turned yellow. But the roots themselves (with rowcover over them) seem fine.

Bright Lights chard with cold-damaged stems in our hoophouse north edge bed after nights at 2F and 8F
Pam Dawling

Over the other side, in the north bed, we have some Bright Lights chard, among other things. Multi-colored chards are less cold-hardy than red ones, which in turn are less cold-hardy than green ones. We know we take a risk in growing Bright Lights through the winter, but we so enjoy the sight of the short pieces of colored stems in our salad mixes that we take the risk. Some of the stems have curled over, probably on their way to dying, but the plants live on, to provide many more salads this winter! And some cooked greens too.

Some of the giant senposai leaves, where not fully protected by the relatively narrow rowcover, have developed tan dead spots, so those leaves can just continue as the plants’ solar panels until we get tired of looking at them and decide they are no longer needed.

Each winter I update my Winter-Kill Temperatures of Cold-Hardy Vegetables list, except this past spring I had nothing new to add. Outdoors, I noticed today that the tatsoi has definitely died, the Vates kale and the spinach have survived (uncovered) and the small garlic leaves don’t seem troubled. The leftover lettuce transplants have been damaged, if not killed.

Winter lettuce and other salad crops

Salad Mix freshly harvested. Lettuce-free mix!
Photo Pam Dawling

We are feasting on our winter salad mixes now, so I decided to write a post to encourage more people to grow winter salads.

Just how viable this is for you depends on your winter climate zone and your facilities. In the coldest of places with nowhere except your kitchen or a windowsill, you can grow sprouts and microgreens.

To grow sprouts, get some organic seeds, soak them in a jar, then fit a straining lid, which can simply be a piece of fabric held in place over the open mouth of the jar with a strong rubber band, or, if using a Mason jar, the metal ring part of the lid. Drain off the extra water, then set the jar on its side, with the seeds distributed evenly along the side. Rinse and drain twice a day, until the sprouts are the size you want. Here’s a couple of websites.

See How to Grow Sprouts at Home, by Beth, or Growing Sprouts at Home, by The SproutPeople

You don’t need to follow these directions word by word, but if you do, it will work. Other methods can also work. Just be sure to rinse and to drain!

The enthusiastic author of How to Grow Microgreens, Sylvia Fountaine, lays out a 6-step process and provides a video. Microgreens are basically seedlings, with stems and green seed leaves. Sprouts are mostly root and stem, as you may have noticed.

For those wanting to grow microgreens professionally, I recommend Andrew Mefferd’s chapter in his Greenhouse and Hoophouse Grower’s Handbook.  

I wrote about our Fall Lettuce Transition in my post Preparing your Hoophouse for Fall and Winter 9/28/22 – This post includes days to germination of lettuce at various soil temperatures. Here are dates when we sow lettuce for growing in various places (not just our hoophouse).

·        For outdoor lettuce I stop sowing August 29, transplant those 9/22 and expect to harvest them 12/10 – 12/31. I add hoops and thick rowcover when it gets cold to keep it growing.

Buttercrunch Bibb lettuce in December. Photo Kathleen Slattery

·        For winter growing in coldframes, I sow 9/1, 9/3, 9/5, 9/7, 9/9 and transplant 9/25 -10/8. Leaves from those plants can be harvested all winter until we need the cold frames to harden off spring transplants in mid-late February. We cover the coldframes with rowcover when it starts to get cold, then plastic-glazed lids as it gets colder, and quilts for really cold spells. These days we are more likely to direct sow spinach in the frames than transplant lettuce. It’s hardier and faster growing.

·        From September 11-17 we sow lettuce every other day in our outdoor nursery bed, to transplant in our unheated greenhouse (double glass windows, solid north wall, rarely freezes in there). We harvest those lettuces by the leaf all winter until we need to dig out the compost they are growing in to fill our seed flats in early February.

Lettuce growing in our greenhouse in November.
Photo Wren Vile

·        On September 15 and 24 we sow lettuce outdoors in a nursery bed, to transplant in our hoophouse 10/15 and 10/24. Those lettuces will feed us all winter, 11/16-3/1, if we simply harvest the outer leaves, rather than cut the head.

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

·        On October 23 we start sowing lettuce mix in the hoophouse. We sow successions of baby lettuce mix directly in the soil 10/24, 12/31, 2/1, 2/15. The last one, on 15 February, will be for harvest starting mid-March, and ending in May when it gets too hot. By then we should be happily harvesting juicy lettuce heads outdoors and will have lost interest in the lettuce mix. We like Fedco’s 2981LO Lettuce Mix OG or Johnny’s Allstar Gourmet Lettuce Mix #2301. For those with challenging growing conditions, both companies offer other specialized selected mixes. 1 oz (28gm) of seed sows about 600 ft, (200m) 

Baby lettuce mix in our hoophouse in winter.
Photo Twin Oaks Community

·        We sow “filler leaf lettuces” in our hoophouse 10/23, and 11/9, to use for gap filling (replacing casualties). 1/25 is our last date for filling any gaps in the hoophouse beds with lettuce plants. After that, we fill all gaps with spinach plants.

Short rows of filler greens in the north edge bed of our hoophouse in December.
Photo Kathleen Slattery

·        So, we have different “stop-dates” for the different types and locations, but no complete Lettuce Stop-date.

o   8/29 Last date for sowing for outdoor row-covered lettuce

o   9/9 last date for sowing to transplant in coldframes

o   9/21 last date for sowing for planting in an unheated greenhouse.

o   9/24 last date for sowing for planting into a double-layered hoophouse

o   11/9 last date for sowing “filler leaf lettuces”

o   2/15 last date for sowing baby lettuce mix in the hoophouse.

How should people not in central Virginia calculate their own stop dates? Using the same numbers as above for the various types and locations:

  1. ​Figure out how late in the year it’s worth having lettuces outdoors. When does the temperature drop to 20°F (-7°C)? Stop sowing for outdoors 3-4 months before then. (Our 8/29 sowing is harvested by 12/31, but our 8/20 sowing is harvested by 11/25). It’s worth experimenting to find which date works best. Outdoors, I have found that lettuce may survive an occasional dip to 10°F (-12°C) with good rowcover. Consult your Extension Service and the website WeatherSpark.com. Fill in your location and look at pages of useful info about the weather where you are.
  2. Figure when your coldframes get down to say 15°F (-9°C). This might be when the outdoor night-time low is 10°F (-12°C), lower if you have a well-insulated coldframe. We have some old quilts to roll on top of our coldframe on nights below 15°F (-9°C). Perhaps lettuce won’t make it all the way through winter in a coldframe in your climate. If so, be prepared to clear the plants when it gets too cold. Calculate back to figure when to sow – allow 4 months to get full sized lettuces.
  3. Figure when your solar double-paned-glass and masonry wall greenhouse gets down to ° (-9°C), or add a small heater with a thermostat to keep it warmer than that. Calculate back to the sowing date, allowing for the fact that plants grow quicker in a greenhouse than outdoors or in coldframes. Maybe allow 3 months.

    Our greenhouse with young lettuce transplants in early October.
    Photo Bridget Aleshire
  4. As far as daylight goes, on 9/24 everyone everywhere is pretty much getting the same amount wherever we live. With a hoophouse, the goal is to grow plants to harvestable size by the time you no longer have lettuce from outdoors (refer to #1). It probably only takes 2 months to grow a lettuce big enough for leaf harvest in a double layer hoophouse. Just be sure not to over-harvest in the winter. We have had lettuce survive a double layer hoophouse temperature of 10.4°F (-12°C) without any rowcover (sometimes called an inner tunnel), and -2.2°F (-19°C) with.
  5. At this point calculations switch to what happens after the Winter Solstice. When do you plan to start harvesting your first outdoor lettuce again? Aim for a two-week overlap with both hoophouse and outdoor lettuce available in the spring. Work back from your hoophouse harvest end date to find the last worthwhile sowing date for filler lettuces. Because lettuce bolts easily when it gets warm in spring, play it cautious. We plan to start outdoors 4/15. We stop transplanting lettuce in the hoophouse 1/25, 2 1/2 months before then. Sowing filler lettuce too late is not really a problem – you can cut it as baby lettuce. But avoid transplanting it just to have it bolt.
  6. If your climate is cold, or you don’t mind only getting one or two cuts from baby lettuce mix, you can carry on sowing it until the soil temperature reaches 86°F/30°C (max temp for lettuce germination). If it is warm, do be sure to water often, so the lettuce doesn’t turn bitter. Otherwise look to you first outdoor lettuce and clear the baby mix when the outdoor crop is ready.
Beautiful baby lettuce mix in our hoophouse in February.
Photo Wren Vile

See my post Lettuce All Year in a Changing Climate 8/31/21. It includes links to all my Lettuce of the Month series, and includes my slideshow Lettuce Year Round and our 2022 Lettuce Varieties List, to help you choose varieties we recommend for different times of year.

For ideas on mixing various crops in winter salads, see Making Salad Mix 10/31/17 and Fast Growing Vegetables 3/24/20. Winter salad mix is also known as mesclun or spring mix (even though we are growing it in the winter). Spinach and many brassicas grow faster than lettuce in cold weather, and make delicious salads.

Bulls Blood Beet leaves
Photo Bridget Aleshire

Also, check my Asian Greens of the Month posts. This post from April 2018, includes at the end links to each of the series. Many Asian Greens make great salad crops. The frilly mustards featured in this post are a good example.

For information on the temperatures that many crops will die at from cold, see Winter Kill Temperatures 2021. I was updating this list each spring. 2022 seems to have slipped by. I don’t think I had any new information, as the winter wasn’t extreme (although we had a long and memorable power outage!).

 

Resilience: Survive, thrive and farm another season!

 

A willow tree behind out herb garden.
Photo Bridget Aleshire

“The willow which bends to the tempest, often escapes better than the oak which resists it.” Sir Walter Scott

I’m reading Laura Lengnick’s book Resilient Agriculture, (review coming soon) and thinking about how growers thrive under varying situations, some of which we have no control over. To adjust to changing weather conditions, to continue after challenges and get the best possible outcome whatever happens, we need to be alert, adaptable and quick on our feet, a bit like a Ju-Jitsu practitioner.

Being ready to tackle whatever happens includes recognizing and building in many options, keeping all options open until the future is clearer, and knowing when and which way to jump. It involves being prepared with needed equipment (or at least phone numbers), and having our filing systems be accessible all year, not in a big heap!

It includes getting good at understanding current conditions and predicting the future, getting to grips with radar maps and how to use Growing Degree Days. It involves keeping records of when certain flowers bloom (phenology), and soil temperatures. This information helps us figure out when to plant according to actual conditions, rather than simply by the calendar, a method which is not useful as climate change takes hold.

A honeybee on deadnettle weeds. Fall deadnettle germination shows that conditions are cool enough to sow spinach. Photo Kathryn Simmons

Making good assessments of conditions is the first step in cultivating adaptability. The second necessary skill-set is the ability to know how to make a swift and effective decision and locate the resources to put that decision into practice. This includes information about soil temperatures and how long various crops take to emerge. Also, knowing how summer crops will respond to extra high temperatures. And how winter crops will respond to horrifying low temperatures. When is it time to cut your losses on a struggling crop and till it in? I do a weekly tour of the gardens and re-prioritize tasks. Growing food is an organic process, non-linear!

These two skills are followed by a review process, so we can learn from what went wrong, as well as what went right! Usually this involves record-keeping, (dates, actions and results) to inform next season. You can list other possible responses to fine-tune your choices next time. Record-keeping can include photos, audio recording, video clips. Whatever works. You may only need to tweak your response in future, or you may want a completely different approach. One of our garden mantras is “Never repeat the same mistake two years running.”

Get Ready for Farming After Anything

Carol Deppe in The Resilient Gardener: Food Production and Self-Reliance in Uncertain Times recommends building in slack, rather than planning to work flat out every day. When something unexpected happens, you’ll have a bit of extra time available to tackle the problem. Personal troubles like injury, health challenges, or family emergencies; or household events like financial problems can require time focused elsewhere; or disastrous weather that affects everyone around you. On her website, Carol has an interview called Food in Uncertain Times: How to Grow and Store the Five Crops You Need to Survive. She says: “The resilient garden is designed and managed so that when things go wrong, they have less impact.” Grow food requiring minimal external inputs, know how to grow staple crops and save seeds. Some years you won’t need to employ these skills, but you’ll be ready when you do.

Being Flexible About Growing Food

Our kale beds after heavy rain. Photo Wren Vile

We have a Garden Shift Honchos Guide to help whoever is leading the crew. It includes general guidelines: “Try to at least get the harvesting done, whatever the weather, (unless torrential rain, tornado, ice storm, thunder and lightning).” It suggests how to choose jobs from our posted task list. My priority sequence is harvest, plant, mulch, prepare beds for planting, hoe, hand weed. The Honchos Guide has hints for contingencies:

  • If the day is likely to be very hot, get the physically taxing tasks done first (especially anything involving shovels).
  • If the morning starts out with a heavy dew, postpone harvesting cucurbits, nightshades, strawberries and legumes until the leaves dry, to reduce the spread of disease.
  • After heavy rain: mulched perennials (fruit and asparagus) are the easiest places to work. Don’t work in sinking mud, it compacts the soil, which means the plants go short on air, and the soil will be slower to drain after future rains. Standing on long boards is an option for harvesting or planting.
  • If heavy rain is expected and you might have to stop in a hurry, do weeding, not planting. It’s a waste of time to hoe if it’s about to rain, or that crop is due for overhead irrigation. Don’t leave pulled weeds on the beds before rain or irrigation. They’ll re-root.
  • If you feel frazzled: choose a big simple task lots of people can do, like weeding strawberries, or hoeing corn. Or choose two tasks geographically close, so it’s easy to keep an eye on everything happening.
  • Choreographing the crew can be hard. It’s handy if everyone finishes harvesting around the same time. Perhaps spread out at first for miscellaneous harvesting, and then end up together on the crop that takes a long time.

Building in Options on the Farm

Stewart Brand in How Buildings Learn: What Happens After They’re Built, advocates for constructing buildings that are easy to modify later, in gradual or drastic ways to meet the changing needs of the people inside. Farms can be looked at similarly. Keep as many options as possible (for crops, cover crops, crop layout) open for as long as possible.

It can be helpful to do some scenario planning, which I learned about in The Art of the Long View, by Peter Schwartz. Scenario Planning is a method of making flexible long-term plans, using stories (scenarios) to help us visualize different possible futures that include not only factors we don’t control, like the weather or the market’s enthusiasm for bulb fennel, but also intangibles such as our hopes and fears, beliefs and dreams. Different combinations of uncertainties and possibilities, including interactions of some major variables in plausible but uncomfortable as well as hoped-for combinations are used to create each scenario.

Sometimes the easiest way to compare scenarios is to set options out in a grid. For instance, in choosing which cover crop to sow following a spring crop that we clear in August-October in zone 7, we can say that the main variables are whether the season is dry or wet, and whether we are early or late planting. We can sow oats from mid-August to early September, to winter-kill, or winter rye once we reach September 1 (before that we risk the rye heading up before winter and self-seeding).

Dry and Early: Sow cowpeas or soybeans with oats, for a winter-killed cover crop. Dry and Late: Sow winter rye or wheat alone.
Wet and Early: Sow a clover mix in August, or hairy vetch with winter rye, 9/1-10/10 Wet and Late: Sow Austrian winter peas with winter rye

Often there are more variables, such as weediness. We might undersow our fall broccoli with a clover mix in August, intending the clovers to become a Green Fallow plot for the following season. The next summer, we assess the situation. If the weeds are bad in July, we disk in the clovers and sow sorghum-sudan hybrid mixed with soy, as a winter-killed cover crop. If all looks well in July, but the weeds are gaining the upper hand in August, we have the option of tilling it in, and sowing oats mixed with soy. If the clover is growing well, and the weeds are not bad, we over-winter the patch, and disk it in February.

Broccoli undersown with clover.
Photo Nina Gentle

Vegetable Crop Options

We have a few options recorded in our calendar:

  • If spring is cold and wet, grow transplants for the second planting of cucumbers and summer squash.
  • If the winter squash patch is too wet to disk, grow transplants, but don’t sow later-maturing varieties.
  • If the soil is to wet to hill the spring potatoes, flame weed instead.

Abundance Options

What to do if your yields are higher than planned: increase sales by giving out samples and recipes, and feature the item on your website. Find sales to new customers (restaurants), process the crop for future out-of-season sale (if you have time), or donate it to a local food bank.

Shortage Options

With a CSA you can keep a list of who gets Sun Gold tomatoes each week, until everyone has had some. This method has the advantage of keeping the time spent picking cherry tomatoes down to a reasonable level. The sharers get some as a treat a few times in the summer, but not every week.

You can mix leaves of several greens in an attractive bunch and call it braising mix, or add unusual crops to bagged salad mix, or make up stir-fry or ratatouille packages. If a crop is really poor, it is often best to till it in and plant something else. For me, this eases the soul and lets me move on. We keep a running list of crops looking for a home, so we can replace failures with fast-growing crops such as radishes, arugula, mizuna, Tokyo bekana, or salad mix. One year when our fall cabbage didn’t fill the area intended, we used senposai, a tasty, fast-growing leaf green. If rutabagas don’t come up, sow turnips – there are very fast-growing turnips, and a small turnip is a delicacy, but a small rutabaga is a sad thing.

Hakurei turnips harvested late January.
Photo Pam Dawling

It helps to have a clear and simple rotation. Our raised bed plan is ad-hoc. We make use of the flexibility: one August we were a bit late getting some tilling done, and we sowed the last cucumbers in the bed which was to have been squash. Cucumbers take a bit longer than squash to reach maturity, and I wanted to get them in the ground as soon as possible. The squash had to wait two more days. Two days can make a lot of difference when planting for fall.

Finding Resilient Crop Varieties

We always read the information about disease resistance when choosing varieties, because mid-Atlantic humidity is so conducive to fungal diseases. Depending on your climate you might pay more attention to the cold-tolerance, or the number of days to maturity. Every year we trial small quantities of one or two new varieties of important crops alongside our workhorses.