Grow Green Manure

Discover how cover crops, such as oats, peas, buckwheat, and more, can give back to your soil and your homestead.

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by Masha Dougherty

This is adapted from Shawn and Beth Dougherty’s book, The Independent Farmstead (Chelsea Green Publishing, 2016).

Finding room in the garden, or time in your rotations, for cover crops can be difficult — don’t we know it! On our farm, The Sow’s Ear, we grow most of the food — and feed — for all of our people and animals. To avoid erosion and loss of soil nutrients, we try to minimize the land kept in cultivation, and sometimes devote a full crop to smothering weeds, or building fertility and soil organic content. Excellent as those goals are, they can seem like obstacles to productivity. So we’re always glad to find new ways of leveraging our covers and green manures to perform as many functions as possible. Who wouldn’t like a green manure that also acts as a nitrogen sponge, mulch, and chicken food and bedding? Or what about a weed-suppressing crop that provides winter food for pigs? Or a nitrogen-fixer that smothers weeds, and then doubles as food?

Benefits of Buckwheat

Take buckwheat. This fast-growing, broad-leaved, warm-weather crop is a quick way to crowd out weeds, and its brittle stems are easy to till into the soil for added organic matter. The normal procedure with buckwheat is to till it when it starts to flower but hasn’t yet set seed.

Buckwheat flowers over a long period of time: Seeds begin to mature from the early flowers while the plant is only half-grown. If we till in our buckwheat early enough to prevent seed set, we lose a great deal of the plant’s potential soil-building organic matter. Not only that, we lose an abundant and reliable honey crop, as buckwheat flowers are a favorite with bees. But if we wait for full growth, buckwheat’s generous crop of seeds means our cover will become a weed infestation in the next crop rotation. Catch-22, you think? Enter the chicken flock! Buckwheat is one of our favorite covers when we combine it with chickens in tractors.

After our buckwheat has begun to set seed — when the lower flowers begin to turn brown — we bring in some of our laying hens in tractors. We slide the chicken tractors over the buckwheat bed, knocking down the plants. The chickens love it. They gobble buckwheat leaves and seeds, as well as some of the many insects the cover crop attracts, significantly reducing the amount of supplemental feed the birds require. As we continue to move the tractor to new areas in the buckwheat patch, the laid-over stems we leave behind become a grown-in-place mulch. This mulch not only shades the soil — thus keeping it cool and moist, a necessary condition for active soil biota — but acts as a carbon sponge, absorbing nitrogen from the hot chicken manure before it washes away or volatilizes. Whatever seeds the chickens miss will sift down to soil level; then, with the next rain, we’ll have a second crop of buckwheat sprouting. Underneath this regrowth, the old stems and chicken manure quickly compost into the soil.

Fast forward a few weeks to when the new cover crop begins to set seed, and we bring back the chickens in their tractor and repeat the whole process. But in our climate, Zone 6, that third sprouting of buckwheat won’t have time to set seed before the cold weather turns this frost-sensitive crop black and mushy, so in spring we won’t have too much trouble with volunteer buckwheat. And we’re willing to pull a few buckwheat plants out of the potato patch in exchange for so much nitrogen, biomass, chicken food, and bee pasture!

Seasonal Cereals

Buckwheat is one of our favorite covers to plant early in the summer, when we can expect a long spell of hot weather. But when a bed becomes available later in the year — such as a potato bed harvested in August — we’re more likely to plant other crops, such as cereal grains, that will continue to grow into the fall and winter. With the soil already disturbed by the previous crop, oats, wheat, and barley are easy to broadcast into the harvested bed; soil contact can be improved by giving the bed a quick raking-over, or, for larger plots, dragging a pallet across the soil. Sometimes we use our chickens to plant this crop. Because the bulk of our birds’ diet is sprouted grain, we pen them in the garden for a few days to clear up bugs and young weeds. We also feed them sprouted grain, scattering larger-than-normal amounts on the garden, where it’ll be mixed in with the loose soil and crop residues; this saves us the trouble of raking in the seed.

Once the grain crop is a few inches tall, we bring in the chickens for another short visit. They love nibbling the tender green shoots, and grazing a cereal crop while the plants are small encourages them to send out tillers, broadening each plant and providing a denser cover for erosion control. Plus, the growing crop incorporates the nitrogen from the chickens’ manure before it can volatilize or wash away, so when the cereal cover crop is tilled into the soil in spring, those nutrients will be available for our next planting.

But we’re not done with the side benefits of this crop yet! In winter, we reap even more rewards when our chickens go over the grain again in multiple passes, this time in tractors covered with durable plastic sheeting, like little greenhouses, where the birds stay warm and protected even while they’re on pasture. The cereal plants are still growing down at the level of the crown, so they continue to provide some grazing for the chickens. In fact, we find that the chickens wintering in tractors lay more reliably than the birds in the henhouse. This seems to be attributable to the fresh green food and thawed soil, as well as the smaller, more easily warmed environment enjoyed by the tractor birds. In spring, the cereal beds will look a little scruffy for a couple of weeks as a result of the chickens’ attentions, but recovery is quick and the grains grow normally. And the plants are all the healthier for the winter application of nitrogen.

Chickens aren’t the only farm animals that can graze a cereal grain cover crop beneficially. If your soils are light enough, sheep can do the job without undue compaction, converting leafy growth in-place to nitrogen-rich manure and urine, while pressing surplus plant litter into the surface of the soil. When your garden space is too precious to be converted every five or six years to pastureland, two or three passes of the sheep over the garden will still contribute significantly to your fertility program, as well as to the feeding of a small flock.

A Multipurpose Mix

A mixed cover of oats and peas is another good cover crop. In addition to its contributions of shading the soil, erosion control, and nitrogen fixation, in its later stages the mix makes excellent poultry pasture. The uncut pasture is great for poultry when we enclose it in netting and turn the birds in for a cool couple of weeks harvesting peas and eating bugs in the shade under the vines. After the pasture’s mowed, the chicken tractors can be moved over the bed so the chickens can eat some of the plant material, and can aerate and add manure to the rest for quick breakdown when the crop is either tilled into the soil or left on the surface to mulch the next planting. If we want the bed to be available for replanting immediately, we cut the cover with a sickle bar, let it dry for a couple of days, and then rake it and put it in the barn loft to be fed to the pigs and cows. The roots, with nitrogen-rich nodules, remain in the soil to provide fertility, while the tops provide the animals with excellent fodder, and we don’t have to wait for the incorporated plant material to break down before we replant that bed.

Pigs also benefit from many of the garden covers we incorporate into our rotation, while adding their own nitrogen-rich contributions to the garden. Some of our favorite pig-friendly plantings are root crops. Spring-planted turnips, mangel-wurzels, and tillage radishes make a fast cover, with broad leaves that shade the ground to discourage weed growth and keep soil temperatures cool. Their long roots puncture our heavy clay subsoil, making holes for water, air, and roots to penetrate, and take up nitrogen that might leach away if the bed were left unoccupied. Young turnips, broadcast and raked into the soil in spring, make good grazing for poultry when they’re a few inches high. If the grazing period is brief, the plants will continue to grow, and their roots will take up and store added nitrogen. Later, root crops can be lightly grazed by sheep — or even cattle, if your soil is light — without damage, so more than one pass is possible. When the roots get really big, they can be grazed again, this time harvesting the whole plant, or they can be pulled and fed to the pigs. If your timing and soil type are agreeable, pigs will be happy to self-harvest! Sometimes, if the garden plot isn’t needed for another planting right away, a cover crop can transition to a main crop left to grow for the whole season. Turnips, mangel-wurzels, and other roots can be cellared for winter pig food.

Summer Shell Beans

Another of our favorite multipurpose covers is shell beans: pintos, black beans, or whatever we have on hand. Planted in close rows, beans will shade out weeds in an otherwise empty bed, as well as fix atmospheric nitrogen for the benefit of the next crop. They fill an important niche in our cover crop lineup too, since they’ll germinate in even the warmest weather. We’ll often harvest some early young beans for our table — the plants don’t mind sharing! And if the weather cooperates, many shorter-season varieties of shell bean will have time to mature before frost. In fall, we cut these plants but leave the roots in the ground, rake the tops, and haul them to the barn to finish drying. If the beans have matured, we’ll thresh them for the farm’s human tenants, and then store the vines in the hay mow above the pig pen to feed out over the winter. Nitrogen fixation, weed suppression, human food, and pig forage — who could resist such a versatile and generous cover crop?

Cover crops are a valuable part of a natural fertility program, and we want to make the most of them. It’s probably obvious by now that our gardens and livestock enjoy an intimate symbiosis. We consider our farm animals necessary co-workers in the farmstead, so there are animals in some part of our garden year-round. We find that the benefits the plants and animals receive from one another save us many steps over the course of a year. Integration, versatility, and multiplication of purposes seem to us the key to every successful natural farm system. Because when farming takes its cues from nature, everyone benefits: plants, animals, soil, environment, and farmers.

Gritty’s Tips

Chicken tractors are movable, bottomless poultry pens that let you pinpoint your birds’ scratching and pooping work — and bug- and weed-suppressing — exactly where it’s needed on your land. We’ve gone through a lot of different models over the years to discover the tractors that offer us the greatest ease of use combined with the greatest versatility. These are the features most important to us on our homestead, The Sow’s Ear:

  • We need a tractor with a small footprint to fit our hilly landscape. Our favorite design is 10 feet by 6 feet.
  • We run laying hens as well as broilers in our chicken tractors, so an arrangement that allows us to install roosts and nesting boxes is ideal. Lightweight boxes made of plastic milk crates covered with vinyl siding can be built and installed using cable ties, and disassembled and stored in moments. We use sassafras saplings for poultry roosts; the strong-smelling wood is supposed to discourage bird lice and other parasites.
  • We need a sturdy design that can be used year-round, winterized with plastic film, and that’s heavy enough to endure strong winter winds. 2×2 and 2×4 planed lumber and 3⁄4-inch metal conduit make a strong frame without too much weight. If you’re worried that winter gales will rip the plastic on your bird pens, staple deer netting over the plastic film to prevent small rips from becoming large holes.
  • Finally, consider the weight of your chicken tractor. Lightweight construction is terrific when it comes to pulling these little bird palaces around, but keep in mind what sort of pasture you’re planning on taking them over. The taller the grass, weeds, or cover crops, the more need of a little weight so the tractor doesn’t “float” on the grass stems and leave gaps underneath, through which your poultry can get out — or predators can get in.

Shawn and Beth Dougherty have farmed together on their Ohio homestead, The Sow’s Ear, for more than 20 years. Follow them at The One-Cow Revolution. Their book can be found in our online store, The Independent Farmstead.

The Independent Farmstead: Regenerate Your Land with Grass-Fed Animals and Intensive Pasture Management

The Independent Farmstead is a must-have resource for those who desire clean, affordable food that’s unmodified, unprocessed, and unmedicated, and for those who long for the security of local food sourcing for themselves and their children. It’s a book for both new and prospective farmers and homesteaders, and for those who are interested in switching to grass-based systems. Best of all, it’s the kind of rare how-to book that the authors themselves view not as a compendium of one-size-fits-all instructions, but as “the beginning of a conversation,” one that’s informative, sincere, and inspiring. This title is available at our store or by calling 866-803-7096.

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