Cover Crops in Summer

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

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.

Iron and Clay southern peas flowering in September. Photo Pam Dawling

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.
Sweet corn with undersown soy cover crop.
Photo Kathryn Simmons

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.

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

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

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.

See my post and article about buckwheat here.

Sorghum-Sudangrass

Sorghum-sudan cover crop after mowing to encourage regrowth.
Photo Kathryn Simmons

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.

Soybeans

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.

Southern Peas

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

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

Occasionally our winter cover crop oats don’t get winter-killed. March photo by Pam Dawling

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.

Root Crops in July

A fine rutabaga (Swede)!
Photo Produce Market Guide

Root Crops in July

Root Crops to Plant in Central Virginia in July

July is not a good month for sowing many root crops in Virginia – it’s hot and for most fall root crops we can do better waiting till August. Yes, it will still be hot in August, but the daylight is getting shorter and so the hot part of the day is also getting shorter.

Carrots: if we really need more carrots, we direct sow our eighth bed of carrots in early July. We only do this if they’re really needed, because carrots grown in hot weather do not have the best flavor. They will not be sweet, they may even be bitter. Our plan is to have grown enough between February and May to last us until late October, stored in perforated plastic bags in the walk-in cooler. But if earlier sowings weren’t all successful, or we ate unusually large amounts of carrots, we can find ourselves sowing them in July.

Use shadecloth to keep the soil damp, or water a lot. Carrot seed will germinate whenever the soil is below 95°F (35°C), provided you can keep the soil damp until the seedlings emerge. You won’t need to do daily watering for long: maybe only 4 days. We flame summer carrots on day 4 after sowing, because we have found that carrots can emerge on day 5 in summer temperatures, despite longer times given in the charts. See Root Crops in May for more about sowing and growing carrots, including pre-emergence flame weeding.

Young kohlrabi plants.
Photo Kathryn Simmons

Kohlrabi: Kohlrabi transplants successfully, unlike carrots and turnips, and this has usually been our method for fall crops. We have sown kohlrabi (Early Purple Vienna and Early White Vienna) in the week beginning July 2, for transplanting 8/3-8/9. Sowing in early August is also possible, for November harvests. Kohlrabi, like other brassicas, can be grown in spring or fall in our zone 7 climate. It’s not actually a root crop, rather a swollen stem, but I’m including it as an “acting root”

Rutabagas: This year we are growing rutabagas (also known as Swedes) again, after several years when we went with more turnips instead. Rutabagas are only sown here in late summer for winter storage. They take longer to grow to a good size than turnips do, so it is necessary to start earlier: 7/15-8/4 here, (mid-August at the latest), allowing 90-100 growing days before a hard freeze. Fall root crops sown too early in the summer can get woody. See the Special Topic for July below for all the details about rutabagas.

Root Crops to Harvest in Central Virginia in July

Potatoes: From mid-June onwards, we can harvest spring-planted potatoes as delicious “new” potatoes. See Root Crops in June for more on this. For maximum yields, hold off on harvesting until two weeks after tops have died. See next week’s post for all the details.

This garden worker loves washing beets!
Photo Wren Vile

Beets: We like to clear all our spring beets by the end of June, but sometimes the job flows over into July. Trimmed beets keep well in perforated plastic bags under refrigeration. Store beets at 32°F (0°C) and 95% humidity.

Carrots: Our third carrots (sown mid-March) should be cleared in early July if not before, and our fourth carrots (sown in late March) and fifth (sown in mid-April) will also be ready to harvest in July. I usually reckon on three months from sowing to harvest for carrots, but they can be faster in warm weather. Don’t leave them in the ground too long, or they will get woody. See Root Crops in June for more on carrots.

Kohlrabi: As with beets, we plan to harvest spring kohlrabi by the end of June, at 3” (7.5 cm) in diameter (or even up to softball size). They get too fibrous if left longer, so we will prioritize getting them up. The base of the globe can be tough, so cut either the wiry root just below the soil surface, or cut higher, leaving a small disc of the globe behind, attached to the taproot.

Turnips: If we didn’t finish harvesting our spring turnips by the end of June, we really need to get them all up in early July. If we have more than we can eat in the next week, we store them in perforated plastic bags in the walk-in cooler, eating them during the summer. Turnips keep for about 4 months at temperatures close to freezing and humidity of 90-95%. Higher humidity will make them rot (rotting turnips are pretty unpleasant!)

Harvested Purple Top Milan and White Egg turnips.
Photo Pam Dawling

Other Root Crop Tasks in Central Virginia in July:

After all the spring-sown root crops are harvested, and the spring-sown greens have bolted, we prepare the emptied beds for summer or fall crops.

Preparing space for summer-planted crops

In July, we will be looking for beds to plant successions of lettuce, cucumbers, squash and beans; our fall brassica transplants, and our first transplants of fall and winter cabbage and Asian greens. In August, we’ll want beds for our last plantings of cucumbers, squash and beans, the never-ending lettuces, fall beets, turnips, winter radishes, kale, and collards. Harvesting the spring roots promptly and storing them gives us time to prepare the beds for their next crop.

Buckwheat

If we have 4 weeks or more before the next crop, we will sow a cover crop of buckwheat in the just-emptied beds. Buckwheat keeps the weeds down and feeds the soil (and the honeybees and other pollinating insects). If there are weeds or lots of crop debris, we will till deep enough to bury that plant matter, then broadcast the buckwheat at a rate of 2–4 oz/100 ft² (6–12 gm/m²), give another shallow tilling, then water and stand back. If there are no weeds or crop debris, there’s no need to till: you can broadcast the seed, and rake it in before watering (and standing back!). As an alternative to broadcasting you can sow rows of buckwheat with the #22 plate on an EarthWay seeder.

Prepare stale seed beds for fall carrots

If you have less than four weeks before you need to sow or transplant the next crop, you can use the time to kill weeds with the stale seedbed technique. Prepare the bed as if you were about to sow, producing an even surface with a fine tilth (surface texture). Then water as if you had sown something, keeping the surface damp by watering as needed. As soon as you see tiny weeds germinating, hoe the surface very shallowly in sunny breezy weather and let the weeds dry out. Make a last hoeing the day before sowing the next crop. This is especially useful for carrots, scallions or anything with tiny seedlings, which cannot easily compete with weeds.

Another method of germinating and killing weed seedlings when there is no crop in the ground is tarping: cover the bed with an opaque waterproof cover after watering the soil. Weeds seeds germinate, but the weeds cannot grow without light and will die.

Solarizing with clear plastic. Photo Pam Dawling

Solarizing is another approach that works well in hot weather: cover the prepared bed with clear agricultural plastic, such as scraps of a hoophouse covering. The heat of the sun bakes any weed seeds near the surface, and also any disease spores or small pests. Larger creatures such as earthworms can burrow deeper into the soil (as they do anyway in hot weather).

Rutabagas, although these ones don’t have much in the way of necks, a usual distinguishing feature.
Photo Penn State

Special Root Crop Topic for July in Central Virginia: Rutabagas

Rutabagas need to be sown in July in central Virginia. To clarify: rutabagas (known as Swedes in the UK) are Brassica napus, closely related to most other brassica crops. Botanically, rutabagas are part swollen tap roots, part swollen stem (the upper portion of the vegetable which forms the neck, the distinguishing feature of rutabagas). There are secondary roots growing in two rows down the sides of rutabagas. Rutabagas are mostly yellow-fleshed with a tan and reddish or purplish skin, although there are white-fleshed varieties. They all have blue-green waxy, non-hairy leaves. turnips are Brassica rapa, like Chinese cabbage and mustards. Turnips come in a range of colors, white or yellow flesh, with white, purple, red or golden yellow skins. The leaves are bright grass green, usually hairy, and not waxy. Turnips do not have a neck or secondary roots growing off the turnip. Rutabagas have twice the nutrients of turnips. And take longer to grow.

Rutabagas are among the hardiest of vegetables, and can be left growing (or at least not dying) until all other crops have been harvested. The flavor improves after frost. For small plantings, plan on 10’ (3 m) per person. Yields of rutabagas can be 75-180 lbs of roots/100’, (35-80 kg roots/30 m): 50% higher than turnips.

Rutabagas come in very few varieties. Laurentian (95 days OP) has a deep purple crown and cream yellow bottom. The uniform 5–6″ (13-15 cm) roots have sweet pale yellow flesh. Joan (90 days, OP), looks similar to Laurentian, with the added advantage that it is somewhat tolerant to club root. Gilfeather (85 days, OP) is sold as a turnip, but is botanically a white rutabaga. Sweeter and later to mature than turnips, it doesn’t become woody even at softball size. Southern Exposure Seed Exchange also has American Purple Top (not to be confused with the Purple Top White Globe turnip) and the Lithuanian Nadmorska a large oval 90d OP.

Fine rows of rutabagas. See the distinctive necks.
Photo Nan Chase

Keys to growing mild, sweet-tasting rutabagas include cool temperatures, sufficient irrigation, and no competition from weeds or over-crowding. The optimal germination range is 59-95°F (15-35°C). Rutabagas are a little slower to germinate. We sow four rows in 4’ (1.2 m) wide beds. Seeds need to be 0.5” (1.2 cm) deep. When flea beetles or grasshoppers are a problem, use rowcover or insect mesh.

Early thinning is especially important for shapely well-developed rutabagas. Thin to 4” (10 cm) within 10 days of emergence, or at least by 1” (2.5 cm) tall, then to 10” (25 cm) when 2-3” (5-7.5 cm) tall. If not well-thinned, they will grow in odd shapes and be small.

Boron deficiency causes the middles of the roots to turn brown. Many common weeds are in the Brassica family, and could harbor pests and diseases that could attack the crop, so use crop rotations, stale seedbeds and clean cultivation to remove the weeds.

Aphids, flea beetles, cabbage worms, harlequin bugs, and grasshoppers can all be a problem. Rutabagas have worse trouble with aphids than turnips. Brassica flea beetles are not the same species as the nightshade flea beetles often found on eggplant. Rowcovers or insect netting and the planting of insectaries (flowers to attract beneficial insects such as ladybugs) can help avoid the problems. Bt can be used for the caterpillars, soaps for the aphids and Nolo bait for the grasshoppers (except where banned in order to preserve rare species of grasshopper).

More information

GrowVeg Rutabaga Growing Guide

Written in Vermont: Gardener’s Path:

Written in Mother Earth News by Sara Pacher:

DIY Network

The main diseases of rutabagas (and turnips) are club-root, downy mildew, powdery mildew, rhizoctonia rot, bacterial scab, and blackleg. All except scab are fungal diseases. Organic methods of prevention are crop rotations and field sanitation (plowing in residues promptly, removing weeds). Club-root fungus is able to live in the soil for up to 10 years, so is hard to eliminate. Avoid all brassica crops in an affected field for 10 years, and be vigilant about eliminating brassica family weeds. (Develop a fondness for spinach, chard and beet greens!)

Our rutabagas are ready from mid-October. Rutabagas (but not turnips except in warm climates) can be stored in the ground all winter. Mulch over them with loose straw once the temperatures descend near 20°F (-7°C). If you don’t manage to eat all the roots before spring, they will re-sprout and you can have an “early spring bite” of greens (a term more usually used for cattle fodder crops).

Rutabagas can store for as much as 6 months in perforated plastic bags under refrigeration. They do best stored above 95% humidity. Prompt washing before the soil dries on the roots will make them easier to clean later.

In the UK, rutabagas are not waxed as they are in North America. In fact, they store well without waxing, and I encourage you to try skipping the petroleum product.

Twin Oaks Garden Task List for June

Admiring a cluster of blueberries. Credit Marilyn Rayne Squier — Admiring a cluster of blueberries.
Credit Marilyn Rayne Squier

Throughout the month of June

Lettuce Factory: Sow VERY harvest garlic, harvest potato onions, s, every 6-5 days, under shade-cloth, #15, 16, 17, 18, 19. Transplant 120/week (1/3 bed) under shadecloth. Transplant #12, 13, 14, 15 this month. Could store seed in fridge.
Deal with Colorado potato beetles, if necessary, every 7 days with Spinosad (or Neem.)
Mulch tomatoes, peppers, eggplant, okra, cukes, asparagus, & watermelons (if not already done).
Mow buckwheat before flowering, and sorghum-sudan at 3-4’ (cut high) to encourage deep rooting.
String weave tomatoes once a week, first 3 rounds with thicker baler twine, then thinner binder twine.
String weaving tomatoes.
Credit Kathryn Simmons

Early June:

1st June: Chit (pre-sprout) seed potatoes for 2 weeks in trays in the light. Let all sprouts grow.
Harvest garlic and potato onions (see Task List for late May)
Sow corn #3, edamame #3, beans #3 (6/7, 24 days after #2). Sow cauliflower 6/1.
Finish planting watermelons (transplants or sprouted seeds). Remove rowcover after 3 weeks.
Transplant leeks, lettuce #12, late tomatoess, (cukes & zukes #2 6/7, if not direct sown). Replace casualties in Roma paste tomatoes, okra & peppers.
Look for Mexican Bean Beetle on the first cloudy day in June. Order Pediobius foveolatus wasps when larvae seen . Maybe predators too (Lacewings, Nematodes).
Weed asparagus in this last week of harvest. If possible give more compost. Mulch again.
Weed cukes & zukes #2 if direct sown. Clear spring-sown collards, kale, if not done already.

Mid June:

Seed potatoes: cut into pieces, with approx 2 sprouts per piece.
Plant & mulch potatoes, Flag end of each row. 1.3 hours for 2 tractor passes.
Sow carrots #7, corn #4, drying beans, limas #2. Consider sowing sunflowers in leek beds to flower in late July/early Aug for grasshopper predators (to protect kale).
Transplant lettuce #13 & 14, zinnias. Clear turnips and kohlrabi.
Weed and thin to 24” winter squash as soon as they have 3 true leaves.
Till between rows of winter squash and sweet potatoes, if not using bioplastic mulch.
Curing onions in a net-covered rack.
Credit Wren Vile

Harvest bulb onions when >50% tops have fallen, (6/11-30), cure indoors for 14 days with fans. Store at 77-95°F or 32-45°F. Take non-storers to walk-in refrigerator after trimming, weighing and recording yield of each variety.
Stop watering spring potatoes to encourage them to finish up. Bush-hog July 1st at the latest.
#5 Spring Tractor Work – by mid-June disk the rest of the garden: Corn #6 &7, any odd areas not done earlier. Get mulch for asparagus, Roma paste tomatoes. Bushhog broccoli, and sorghum-sudan 4’ tall or more (as well as spring-planted potatoes)

Late June:

Sow drying beans, cucumbers #3 (slicers only), zukes, summer squash #3, 6/23, beans #4, edamame #4 melons #2 by 6/25, cowpeas #3.
Sow brassicas for fall, (use fall brassicas spreadsheet). 2 or 3 sowings of each variety (each enough alone), a week apart, as insurance.
Transplant lettuce #15, “filler” leeks to make up for any shortfall in earlier sowings.
Undersow corn #3, 4 at 2^nd cultivation (when 6-12” tall) with soy, or just till.
Clear beets. Clear pea stakes if not done earlier
Get program for Louisa County Ag Fair, (1st w/e of August), to enter produce.
Sort Potato Onions 6/20-6/30 (without breaking clusters), starting with the biggest, and remove rotting ones. Remove ones >2” for eating, or refrigerate for September planting; or sell to Southern Exposure Seed Exchange before 7/31. Continue to cure small and medium ones for 2 months or more in total, with fans. Use Worksheet and Log Book. Be sure to write down where you store them!
Store any seeds not needed until fall (okra, nightshades, peanuts, melons) in basement
Snip, sort and store garlic after curing 2-4 weeks. Store at 60-70°F (basement), never 40-50°F. Seed garlic is best stored in garden shed (or 32-35°F).

Cover crops: can sow buckwheat, millet, soy and sorghum-sudan during June. Japanese millet is good for small equipment. Sorghum-sudangrass is not!

Perennials: Water all.

Till in oldest strawberry beds after potting up any needed runners. Bushhog or mow, weed and mulch strawberry beds, mulch paths. Don’t compost until August.
Mow aisles in grapes and raspberries.
Weed, compost and tuck mulch round asparagus, (late June/early July).
Weed and mulch rhubarb.
New grapevines: remove side branches and fruitlets. Late June/early July:
Make a visit to the new blueberries and grapes, log progress, tie in, prune if needed. Water, weed, & harvest blueberries & select plants to propagate.
Blueberry Harvest: 12 person-hours 2 x week from 5/30 to 7/8, then 6 person-hours 2 x week till 7/27. 7 weeks total.

Harvest: Beans, beets, beet greens, blueberries, broccoli, cabbage, carrots, celery, chard, cherries, cucumbers, fava beans in one harvest mid-June, fennel, garlic, kohlrabi, lettuce, onions, peas, hoophouse peppers (green), potato onions, raspberries, scallions, squash, hoophouse tomatoes, turnips, zucchini. Harvest early potatoes from 6/15.

Store for 100 people,1 bag cabbage/week until 9/25 when fall cabbage matures. – say from 6/25, store 12 bags. Store ½ bag beets/week until 9/20 when fall beets mature – say 6 bags from 6/20.

Grapevines and Solar Panels. Credit Bridget Aleshire — Grapevines and Solar Panels.
Credit Bridget Aleshire

Twin Oaks Garden Task List for May

Turnips interplanted with radishes - two spring crops from one bed. Credit Kathryn Simmons — Turnips interplanted with radishes – two spring crops from one bed.
Credit Kathryn Simmons

During the Month:

Lettuce Factory: Sow heat-resistant lettuce outdoors, every 8 to 6 days, #10, 11, 12, 13, 14. Transplant 120/week (1/3 bed). #7, 8, 9, 10, 11 this month.

Deal with potato beetles with Spinosad [or Neem] once larvae are seen, if >50 adults/50 plants or >200 larvae/100 plants. Spinosad: Spray when bees not flying (early morning or late evening.) Shake well, 1-4 Tbsp/gall. Expect to need 1.5-2 hours and 9-10.5 galls. Clean and triple rinse the sprayer. Do not flush in creek or pond. Repeat if needed in 6-7 days – could spot spray where larvae are seen. Flame weed potatoes before 12” high, if needed.

Deal with asparagus beetles, if necessary. See notes under April.

Early May:

Flat of home-grown sweet potato slips. Credit Kathryn Simmons — Flat of home-grown sweet potato slips.
Credit Kathryn Simmons

Continue cutting sweet potato slips until we have enough.

Transplant when hardened off: celery, celeriac, lettuce #7, main tomatoes (2’).

Set out drip tape & bioplastic mulch , transplant Romas (2’), peppers (18” when soil 70°F, dogwood blooms dropping), hot peppers, and melons #1, sweet potatoes.

Sow peanuts (120d), asparagus beans in bed w/ celery, okra, sunflowers. limas #1, cow peas #1 (68d)

Roll out driptape and bioplastic mulch for watermelons.

Cover Crops: Sorghum-Sudan, soy, buckwheat, or pearl millet as summer cover crops, now frost is past.

Mid-month:

Plant sweet potatoes, 16″ apart, with 4-4.5′ between ridges, 5’ at edges of patch. Install drip irrigation on ridges and plant at every other emitter. Ideal if soil temp is 65°F for four consecutive days before planting. If weather dry, dip roots in mud slurry before planting. Plant 2-3” deep, with at least 2 nodes in ground, and at least 2 leaves above ground. If slips are long, plant horizontally to increase production.

Transplant lettuce #8, eggplant (2’ apart, single row in center of bed, spray off flea beetles with jet of water & cover immediately), watermelon, insectaries, (okra if not direct-sown – mulch later, when soil warm).

Set out drip tape and biodegradable mulch and transplant melons and watermelons at four weeks old max. Cover for 3 weeks. Move rowcover off broccoli (12 pieces) and strawberries (~8 pieces) Watermelon needs 12 pieces.

In greenhouse sow tomatoes #3, filler watermelons & Romas. Sow cukes & squash #2 if spring is late and cold, and direct-sowing not wise.

Sow beans #2 (5/14, 28 days after #1), edamame #2, carrots #6, sunflowers.

Till between rows of corn #1 & transplant in gaps and/or thin to 8”.

A bed of various varieties of onions. Credit Kathryn Simmons — A bed of various varieties of onions.
Credit Kathryn Simmons

Weed onions 3 weeks before expected harvest date, and broccoli.

Garlic: Harvest garlic scapes, remove mulch from garlic, and weed. Move mulch to weeded broccoli.

Check maturity of potato onions and garlic. Likely harvest order is fall potato onions 5/25-6/10, hardneck garlic 5/30-6/15, spring potato onions 6/3-6/18, bulb onions 6/11-6/30, softneck garlic 6/5-6/15.

#4 Spring Tractor Work mid-May – Disk areas for June potatoes, corn 3,4,5, & later succession plantings of beans, squash, cucumbers.

Late May:

Mow between no-till paste tomato rows before mulching with hay. Fill gaps, weed, tuck mulch. Set up posts and string weave the tomatoes, using thick baler twine for lower 3 rows. Really try to keep up with weekly string-weaving.

String weave 1 row around peppers, using short stakes.

Clear empty coldframe and mulch with cardboard or plant something.

Till each corn twice, undersowing at 2^nd tilling (30 days), when 12” high, with soy for #1-5, oats/soy for #6. Thin corn to 8”. Avoid cultivating corn after it’s knee-high—roots are shallow.

Sow corn #2, cowpeas #2; cukes #2 (picklers and slicers), summer squash & zukes #2 5/24 (or in greenhouse 5/14, transplant 6/7), watermelons #3, winter squash 5/26 (put woodash with seeds to deter squash vine borer). If squash sowing is late, don’t sow Tahitian butternut – slow. Cover cucurbits (perhaps not winter squash) against cucumber beetles. Max. cuke beetle population is mid-May; keep susceptible plants well-covered until flowering.

Transplant lettuce #9, 10, 11; Roma paste tomato replacements for casualties, insectary flowers. Fill gaps in eggplant, peppers, melons, watermelons.

Store any seeds not needed until fall or next spring, in basement (radishes, onions, winter squash, watermelon).

Harvest fall planted Potato Onions in dry weather, after tops have fallen, (5/25-6/10, spring planted 6/3-18). May not all be ready at once. Handle gently. Dry as clusters in barn on wooden racks for 1-2 months, using fans. Service fans or buy new as needed. Eat potato onions >2.5” without curing, unless yield is very low, in which case label & refrigerate, then plant in September. Weight after drying for 1 week is approximately twice the final weight. First sorting is late June. Use the Worksheet and Log Book

Hanging garlic in vertical netting. Credit Marilyn Rayne Squier — Hanging garlic in vertical netting.
Credit Marilyn Rayne Squier

Harvest garlic when 6^th leaf down is starting to brown on 50% of the crop (ie .5 green leaves, so that 5 skins cover cloves), or cut open horizontally- when air space is visible between. stem and cloves it’s time to harvest. [Could replant small cloves immediately for garlic scallions.] Allow 15 mins/bucket harvesting and 15 mins/bucket for hanging in netting in barn,.

Till garlic area, sow soy & buckwheat to control weeds until fall carrot planting.

Plan fall and winter crops for raised beds.

Cover crops: can sow buckwheat, soy, millet, and sorghum-sudan during May.

Perennials: Put up blueberry netting before fruit sets. Weed & water & top up mulch. Mow grape & fall raspberry aisles. New grapevines: remove side branches and fruitlets. Weekly: visit grapes and log progress 4/20-5/30. If asparagus weeds are getting out of hand, mow down one or more rows to keep control.

Our Concord grapes in late May. Credit Bridget Aleshire — Our Concord grapes in late May.
Credit Bridget Aleshire

Harvest: Asparagus, hoophouse beans, beets, beet greens, broccoli, cabbage, first carrots, chard, collards, garlic scallions, garlic scapes, kale, kohlrabi, lettuce, peas, radishes, rhubarb, scallions, senposai, spinach, hoophouse squash, strawberries, turnips, hoophouse zucchini. (Clear spinach, senposai, collards, kale, probably in that order)

Grasshoppers and hoophouses

This week I did some research into grasshoppers, as we have have been losing lots of new seedlings (kale, spinach, beets and turnips), and the beds are leaping with little jumping critters. Definitely bigger than flea beetles, I think they are baby grasshoppers. usually we get them in mid-August, not the first part of September, but climate change is here, so things are not “as usual” any more.

I learned that we had inadvertently been providing ideal grasshopper habitat by two things we have been doing. Or rather, two things we have not been doing. Grasshoppers like tall unmowed grass, and yes, we have been very slack about mowing around the edges of the gardens this year.Next I read that if you want to keep grasshoppers away from your vegetables you could sow a small patch of grains nearby, but not too close. The light-bulb lit up! We use a lot of buckwheat and soy as summer cover crops in our raised beds and for one reason and another, some of them got over-mature and the buckwheat set seed. No doubt the grasshoppers were having a feeding frenzy there! We paid in other ways too – the self-sown buckwheat has come up in our fall crops, and been a challenge to remove before it swamps the crops. Next year, more timely mowing and tilling. (We have a mantra not to repeat the same mistake two years running.)

I read up about Nosema Locustae bait. It’s a parasite of grasshoppers that you can spray in the spring when there is a growing population of young grasshoppers. Some of them eat the bait and incubate the parasite, then other grasshoppers eat those ones, and the disease spreads. It’s an organic answer, and doesn’t give an instant result. Some people say it’s the following year after applying it, that you’ll see a diminished horde. Sounds worthwhile, to me.

Meanwhile, our main task this week has been replacing the plastic and doing major renovations to our 30′ x 96′ hoophouse (high tunnel). We scheduled this last week, but got too much rain and wind. It’s time to replace the plastic, and we also need to replace the baseboards and shore up the west wall, which has been leaning in for some time. The two layers of plastic came off fairly easily, but it’s been tough going since. All the screws and bolts are rusted up, of course.

In order to stabilize the framework, we decided to put a screw in each connector where the purlins join the bows. That’s 25 x 6! And to prop the west wall up, we got some steel tubing to make diagonal braces. Dim-wittedly, I bought connectors that only work on two pieces of tubing at right angles to each other, not on a diagonal. So I had to do some hasty shopping. We had hoped to finish before rain and before Tuesday, but I think we’ll be there longer than that. Every little thing that doesn’t go according to plan sets us back a bit more. I’ll tell you how it’s gone next weekend.

It’ll be a joy when it’s all done and cozy in there for the winter, and we have lots of salads and cooking greens. Can’t wait!