Barbara Pleasant – Sustainable Market Farming

Cover Crops for May: Buckwheat

Buckwheat in flower in September.
Photo Pam Dawling

This is the first of a monthly series on cover crops, which will take us through a whole year, to April 2024.

Why Grow Cover Crops?

See my post Cover Crops in Summer.

Cover crops suppress weeds and provide a boost to soil organic matter.
Keep live roots in the ground as much of the time as possible, to feed the microorganisms in the Soil Food Web.
Here is a diagram of the Soil Food Web: https://upload.wikimedia.org/wikipedia/commons/8/89/Soil_food_webUSDA.jpg
Roots 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 sequestering 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.
Too often, gardeners grow cover crop only in the off-season, to protect the soil in winter, and assume it’s not a summer option. But it is, and planting summer cover crops provides many benefits.

Focus Cover Crop for May: Buckwheat

A bed of young buckwheat with a cosmos plant to attract beneficial insects. Photo Pam Dawling

I have a blog post Buckwheat, a wonderful summer cover crop, introducing an article I wrote for Growing for Market magazine. See that post for basic details I mostly won’t repeat here.

Buckwheat (Fagopyron esculentum) is a fast-growing warm-season broadleaf annual that is a very useful cover crop. Its special strengths are in weed-suppression, attracting beneficial insects, improving the soil tilth (aggregate structure) with its fibrous roots, and extracting potassium, calcium and phosphorus from the soil to the benefit of following crops. Buckwheat is almost three times as good as barley in scavenging phosphorus, and more than ten times better than rye (a poor phosphorus scavenger). Because buckwheat is not related to any of the common food crops, it is simple to include in rotations.

Buckwheat can be sown up from your last frost up to 35 days before first fall frost. Buckwheat can close its canopy in just two weeks, preventing the soil baking in summer conditions. Because it matures quickly, and self-sows, it can be used in several successions with tilling between, to suppress some perennial weeds.

Flowering buckwheat in September.
Photo Pam Dawling

Buckwheat can do fairly well on poor soils, is tolerant of a range of soil pH and is an easy crop to deal with manually or with small-scale equipment. Even mature buckwheat plants are easy to deal with using manual or small-scale equipment. You can just pull up the plants by hand, or use a hoe or scythe to slice them off at the soil line. You can chop them into the soil, or gather them up and compost them. Or you can use a no-till method, let the dead plants die into a surface mulch and plant through them.

Buckwheat yields only a couple of tons per acre, but does it in only six to eight weeks. If you want to increase the (admittedly sparse) biomass, cut down buckwheat just before it reaches 25% bloom, to a height above the lowest leaf node. Buckwheat will regrow rapidly and you may even be able to make a second cutting.

Buckwheat also makes good food for poultry or rabbits, and chickens love the seeds. It does not provide good forage for larger livestock.

Beds of young buckwheat.
Photo Bridget Aleshire

Barbara Pleasant, in her 2009 article Cover Crops, described Rhizodeposition as a special advantage of using cover crops. Many plants release sugars and other substances through their root hairs into the soil. They are solar-powered pumps, sending energy down into the soil, causing the root tips to host colonies of useful microorganisms. As the roots move deeper, the microbes follow. With vigorous winter cover crop plants, like oats or rye, this process goes on down to 6 feet (much more deeply than you should dig). Buckwheat doesn’t go very deeply at all, but it can be working for you, which is much better than leaving the soil empty and drying out.

Buckwheat in flower in June. Photo Pam Dawling

Buckwheat Resources

e-Organic: Buckwheat for Cover Cropping in Organic Farming and a video clip
Mark Schonbeck, Principles of Sustainable Weed Management in Organic Cropping Systems
Mark Schonbeck and Ron Morse, Virginia Association for Biological Farming, Seeders: Using Manually-operated Seeders for Precision Cover Crop Plantings,
Country Living How to De-hull Buckwheat with the Country Living Mill
Harvey Ussery, The Modern Homestead, Four Outstanding Cover Crops for Summer
Cornell Buckwheat Cover Crop Handbook (thorough, but not organic) .

Secondary Cover Crops for May

Soy, mustard, sunn hemp, southern peas are all also good summer cover crops, and I will say more about them in the next few months. See Cover Crops in Summer.

Sunnhemp cover crop at Nourishing Acres Farm, NC.
Photo Pam Dawling

Sunn hemp, a nitrogen-fixing legume from the tropics, can grow as tall as 9’ (2.7 m) in a few months. Sow sunn hemp from a week after your sweet corn sowing date, up to 9 weeks before your first fall frost, which will kill it. It tolerates a wide range of soils (but not if waterlogged). 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 (as with all cover crops) will work better to smother the weeds.

If you sow sunn hemp in a summer gap between spring and fall vegetable crops, it will provide a nitrogen boost for the fall crop, because it is a legume. 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).

We have taken to sowing sunn hemp as a summer cover crop in our hoophouse, and lopping it periodically with hedge shears to an ergonomic elbow height. This is because we don’t want it to shade crop plants further back (north). The fallen tops make a nice “forest floor” carbonaceous mulch.

Mustard we don’t grow as cover crops, although I do have experience of growing it in England, where it is one of the favorite cover crops for short crop gaps, or in preparing areas reclaimed from pasture or lawn. We have too many harlequin bugs, and we hope to break their lifecycle by having a summer month without any visible brassicas. (We do often have fall brassica seedlings growing under insect netting.) Also, our “crop portfolio” has plenty of brassicas already, and we’d rather have a better rotation, with brassicas less often.

Mustards can decrease weeds, or certain pest nematodes, if you grow the right kind.

Soybeans as a cover crop
Photo agcrops.osu.edu

Soybeans are a great summer cover crop and they are also a legume, so they add nitrogen to the soil. They have good shade tolerance and tolerance to foot traffic (that is, people harvesting crops on either side. Because of this, we like using soy to undersow in sweet corn.

Southern peas are another warm weather cover crop option. They are also a legume, and so will add nitrogen to the soil. Iron and Clay is the sprawl variety best known for cover crop use, but other varieties also work.

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

Cover Crop Planning

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.

See Harvey Ussery Four Outstanding Cover Crops for Summer.

More about Jamaica’s Source Farm Project

A bunch of bananas growing at face level outside my door on the path to the office at Source Farm, Jamaica.
Photo Pam Dawling

At last I got the photos from my Jamaica trip from my camera to the computer. I didn’t take many photos – as I said in my other Jamaica post, it rained most of the time. As you see in the photo above, bananas grow well, the land at Source Farm is hilly, the office is a repurposed and repainted shipping container

At the beginning of June the BBC visited Source Farm and made a podcast as part of the On Your Farm series, and called it Jamaica’s Organic Revolution.

You can listen to all 22 minutes of it for free, and hear the people I stayed with at Source Farm as well as Mr Brown, one of the farmers I met with. I can only link to the program, not embed it, so click the link below

http://www.bbc.co.uk/programmes/b08skyk0

Source – BBC News

I thoroughly enjoyed listening to the voices of my new friends, and being reminded of the farm and the countryside.

Viewing my photos reminded me also of the “domestic wildlife.” First the friendly ones:

Gecko or “Croaking Lizard” on my wall at Source Farm
Photo Pam Dawling

Then the creepy crawlies, the two inch millipedes that were everywhere. You have to be careful not to crush them, because the liquid inside them can cause burns. I never had that problem, and scooped them up by the handful to throw outside each night, only to find them back inside by morning. I concluded that each house had its allotment of millipedes and it was best to ignore them!

Millipede and electric outlet in my room at Source Farm.
Photo Pam Dawling

Things I noticed and learned from the farmers about growing crops in the tropics have led me to think more about how plants respond to temperature and day-length, and I want to learn more about this when I have time. As I said in my Asian Greens for June post:

“Last month I was in Jamaica and saw how they can grow kale in very hot weather. “

I had a comment from a reader about successfully growing Joy Choi in hot summers as well as Tokyo bekana. It’s revelation to me that at least some brassicas can grow in hot weather as long as the temperature never drops below 50°F (10°C), which triggers bolting.

Swiss chard I take for granted as a summer leafy green – it’s a biennial and usually won’t bolt until the second year. The Ruby chard seems the most prone to bolting. We’ve given up that one in favor of Bright Lights, as well as Fordhook Giant green chard. Chard is popular in Jamaica too.

Fordhook Giant green chard.
Photo Bridget Aleshire

A green which is not common here in the US, but is very popular in Jamaica is callaloo, which is a type of amaranth. I enjoyed eating it at Source Farm. I tried growing it in Virginia one year, when I was researching summer cooking greens in spring 2015 for an article in Growing for Market. Here’s what I said then (when I maybe misspelled callaloo):

Vegetable amaranth, Amaranthus species.

In spring use the young leaves for salad. Larger leaves make tender and nutritious cooked greens. Calaloo is an amaranth (but sometimes other crops have this name), used to make a green Caribbean stew. Joseph’s Coat, Amaranthus tricolor, is an eye-catching plant with red, green, and yellow leaves that may also include patches of pink, bronze, purple and brown. This tropical plant thrives in really hot weather. It is a huge plant, 4-6’ tall. Carol Deppe in The Tao of Vegetable Gardening recommends All Red for a spectacularly colorful leaf, especially for salads, and Green Calaloo and Burgundy for fast-growing greens. She reports they all taste the same to her raw, and all taste the same when cooked. So choose by preferred color and rate of growth.

Seeds should be started indoors in spring, and transplanted once all chance of frost has passed, when it is time to plant corn. Alternatively, broadcast with aim of getting plants 4” apart. Each time the plants reach 12” tall, harvest the top 8”. Pinch back often to push out new leaves and prevent reseeding (it can become a weed problem). If your farm has lots of amaranth weeds, you won’t want to risk adding another. Also, if weed amaranths are eaten by the striped fleabeetles, your cultivated amaranths will also suffer. (Those are the two reasons we gave up on them.)

William Woys Weaver (Saladings, Warm Weather, Mother Earth News) is a fan of ‘Bliton’ or ‘Horsetooth Amaranth’, Amaranthus lividus (Amaranthus viridis). He reports that it is the easiest and most prolific of summer greens. Seed should be started indoors, except in the South. Transplant seedlings when it’s warm enough to plant beans (Frequent advice for many of these hot weather greens). Alternatively, broadcast where it is to grow after all danger of frost is past. Thin the seedlings for salads or harvest plants about 12” tall and cook like spinach. When the plant is older, the stems get too tough, and then only the leaves and new shoots should be used. In parts of the South, it has become a weed – “Grow responsibly,” as Barbara Pleasant says in her Mother Earth News blogpost Warm Weather Spinach Alternatives.

Green Amaranth/Calaloo
Photo **Baker Creek Seeds**

The hoophouse in fall and winter, last spring planting dates, MEN Asheville

Last week I embedded my slideshow on using a hoophouse in spring and summer. Here’s the slideshow for the hoophouse in fall and winter, including some bonus material I didn’t show at the West Virginia Small farms Conference, due to time constraints:

Hoophouse in fall and winter dawling from Pam Dawling

Of course, this isn’t the season to be planting winter crops (despite the recent weather!), but you can get ideas for next winter and plan them in to your hoophouse layout, and order seeds.

I’ll be giving these two presentations at the Mother Earth News Fair in Asheville, North Carolina. It’s April 11-12 at the Western North Carolina Agricultural Center, Fletcher, NC. There you can hear me speak as well as see the slides; you’ll get a handout and you can ask questions. The Hoophouse in Spring and Summer is on Saturday 10am-11am on the Organic Gardening stage and The Hoophouse in Fall and Winter is on Sunday at 11.30am -12.30pm on the GRIT stage. I’ll also have a book signing.

One row of grapes (mostly Concord) from the north, in a warmer spring. Credit Kathryn Simmons — One row of grapes (mostly Concord) from the north, in a warmer spring.
Credit Kathryn Simmons

Meanwhile, this week in the garden, the snow has almost melted, and we had two garden shifts, on Saturday and Monday afternoons. We pruned grapes and gave compost to our younger blueberries. Mud season is everywhere. The snowmelt is being augmented by rain today. When will we ever be able to till the garden? We planted nothing in February except some shallots. “Normally” by now we would have sowed two beds of carrots, nine of peas, one of turnips and some radishes and scallions, transplanted 4 beds of spinach, one of cabbage, and a third of a bed of lettuce. We’d have beds ready for sowing more carrots and 4 beds of beets and transplanting three beds of kale and one of collards. We’d be preparing the potato patch for planting. Instead we are looking at at least a couple more weeks before we can till and several weeks before we can disk.

Obviously we can’t do it all, even if the weather suddenly became glorious rather than rainy! We have to make some tough decisions about where to take our losses. The potatoes we can just plant later, although it will cause us problems later, when we want to end the potatoes and prepare to plant fall broccoli and cabbage in the same spot. it will likely mean lower yields, as we can’t at this point find a new home for the broccoli and cabbage without infringing on our crop rotation.

The peas still have a chance. We plant peas in the middles of beds of overwintered spinach. So we don’t need to till, just weed, then sow. We reckon we can plant peas until 3/31 in central Virginia. Veggie Harvest agrees.

I’ve been researching last worthwhile planting dates for spring. There are plenty of tables of last planting dates for fall, but fewer for spring. Here’s what we came up with:

3/16 Turnips (Virginia Extension) – so we abandoned plans for those.

3/31 Peas (date from our records, confirmed by Veggie Harvest)

4/1 Kale and collards transplants (our records, confirmed by Veggie Harvest)

4/8 Spinach transplants (our records. Va Ext says 3/16, VH says late April, Barbara Pleasant says average last frost date. Ours is 4/20). So we’re in the middle, maybe risk later than we were going to. But it can turn hot fast here!

4/15 Beets (our records. VH says late April, so maybe we could try a little later)

We also have 3/15 as the last spring date to sow clovers and 3/31 as the last spring date to sow oats for cover crop.

We’re going to reconsider each week, looking at this list for reference. We’ve already also decided to cut out two beds of spring carrots, as we reckon we wouldn’t have time to deal with them all, even if we could get them planted. we have plenty of stored ones from the fall planting, still in good shape.

And, despite the challenges outdoors, we are potting up peppers for the hoophouse.

Pepper seedlings in the greenhouse. Credit Kathryn Simmons — Pepper seedlings in the greenhouse.
Credit Kathryn Simmons