Table of Contents
1: Soil Care Basics | 2: Increasing Humus | 3: Maximizing Cover Crops | 4: Bare Ground and Tillage | 5: Plant Care | 6: Beneficial Insects | 7: Habitat Plantings | 8: Other Strategies for Insects | 9: Yet More Strategies | 10: Gardening All Four Seasons | 11: Eating Fresh
3. Soil Care: More on Cover Crops
When to sow cover crops
There is a cover crop for any need and for any season of the year. Planting cover crops in the fall to cover garden beds over the winter is excellent practice—beds under a cover are protected from erosive effects of winter weather. In addition, even if we do not see any obvious growth during the dormant period, root growth continues except when the ground is frozen. Generally an overwintered cover produces a good deal of spring growth before it is time to turn it under in preparation for planting. Good overwinter crops might include wheat, barley, oats, and crucifers. Some will survive the winter, some will winterkill, all will benefit the soil. Rye and vetch are the cover crops that can be started the latest in the fall and still make a cover before the dormant season. Neither will winterkill in Virginia’s climate, so will furnish that lush spring growth. In addition, the vetch, a legume, sets nitrogen in the soil.
In the spring, good covers include the grain grasses, the crucifers, clovers, alfalfa, and cold-hardy peas. Buckwheat, though extremely sensitive to frost in the spring, is a wonderful quick cover anytime in the frost-free period, easy to start even when it is hot and dry in summer, flowering in as little as thirty days! Soybeans and peas of the cowpea and blackeye group are also excellent covers to use in the heat of summer. (And remember they are legumes, so you can use the nitrogen they fix in your cropping strategy.)
Removing cover crops
Some cover crops are hard to kill, hard to turn under with the tools at hand for the home gardener. Rye, for example, with its matted, tough, extensive root system, is tough to turn in, even using a power tiller. Since I prefer to minimize tillage (see below), I try to find alternatives to chopping or cutting a cover crop into the soil.
- Winter-killed covers
- A great way to go with overwinter covers is to grow those which do not have to be tilled in at all, because they have already been killed by the more severe cold spells of winter and are now lying on the beds as a beautiful mulch, grown in place. My favorite winter-killed covers are oats and peas. Both will reliably winter-kill in our climate. Oats should be easy to get locally—whole oats such as are fed to horses, for example, will do just fine. The peas referred to are pisum arvense, feed or cover crop pea varieties in the same family as the common garden pea. I use such peas to make my poultry feeds, so simply draw some out of the bin and plant when I need a pea cover crop. For those without access to my sources, though, winter peas are not easy to find locally. They can be purchased from FEDCO. Getting the timing right for winter-killed covers can be tricky. I like to start mine by the third week of September. However, if I have to wait to finish the harvest of a previous crop, I can start as late as early October. I usually use a mix of both oats and peas. An early start is important to get a lush, vigorous stand which—because these species are relatively cold hardy—will grow through the early frosts with no problem, becoming quite thick and tall. Then, when the seriously cold weather comes in, they die and collapse—leaving a beautiful mulch-in-place to cover a bed of asparagus, say, or through which you could set transplants of broccoli, cabbage, tomatoes, etc. come spring.
- Cutting below the crowns
- Using a hoe, you can cut off living cover crop plants at ground level. The roots decay in place, improving soil structure, and the tops can be left in place to dry and serve as a mulch.
- Uprooting by hand
- With a cover such as rye, with its tough, matted root system, killing it with a hoe would be a pretty tough job. I sometimes use a broadfork to loosen the soil, then pull the plants out by hand, again simply laying them on the beds to dry and serve as mulch.
- Poultry power!
- The above two are obviously labor-intensive, involving an attack on a tough living sod with hand tools. (Don’t think it will be much easier with a power tiller. I have many times attacked a robust rye cover with a power tiller—the job took about as long as with the hand tools, the tiller was noisy and stinky, and it beat me half to death! I prefer hand-to-plant combat.) There is an easy way to turn that cover crop in, however. Let your flock of chickens do it! You do have a flock, don’t you? If not, and if it is at all possible for you to have one on your homestead, you would find there are a number of ways to use the flock to help with the work of the garden, the orchard, and other homestead projects. When I want to “chicken-till” a plot with a cover crop, I set a small portable shelter in the middle and surround it with electric net fencing energized by a solar-powered fence charger. I feed, water, and collect eggs—exactly as I would if they were on the pasture, or even locked in a henhouse—and forget about breaking my back with that cover crop. The chickens do what chickens love to do—scratch, and scratch, and scratch. They never tire, they don’t break down, they don’t require gas and oil, and the sounds they make are much more pleasant than a tiller. After a week or two—varying with the type of cover, the size of plot, and the number of birds—they completely turn in the cover crop, and I can move them elsewhere and plant. Please note that in the process they have:
- Eaten nutrient-dense foods (living green plants, earthworms, etc.) of a quality I cannot hope to match, boosting their health and vitality.
- “Sanitized” the area for slugs and slug eggs. It will be months before the slug population can recover to damaging levels.
- Tilled in the tough over-winter cover crop while I was busy with other projects.
- Incorporated their droppings, now finely dispersed, boosting the biological activity in the top few inches of soil and hastening the breakdown of the cover crop. (Talk about multi-tasking!)
Undersown cover crops
Described above is the practice of cover cropping when there is no food crop on the given space—over winter, in the spring before a bed is planted, between crops in the middle of the growing season, and in the fall after harvest of the main crop. However, it can be quite difficult fitting in a cover cropping program around the needs of the main crops. Buckwheat is a rapidly growing cover, but cannot be planted in early spring or fall because of sensitivity to frost. Clovers are excellent fixers of nitrogen, but need to be in place most of the season in order to do so. By the time we get the main crop off a bed in the fall, it may be too late to start an effective cover crop. Fortunately, there is a strategy for combining cover cropping with the growing of the main crop: undersowing an appropriate cover below the main crop.
In my experience, Dutch white clover is probably the best choice for such use. It is low-growing, thus will not interfere with harvest of the main crop (pole beans, peppers, tomatoes, etc.). It makes an amazingly fast start with the cooler temperatures and greater soil moisture of spring—indeed, along with buckwheat it is the fastest germinating cover in my experience. It provides a tight cover which smothers out most weed growth. At the same time, since it fixes its own nitrogen, it doesn’t compete heavily with the main crop for soil nutrients. And it does not deprive the main crop of water—indeed, because of its tight cover on the soil, it helps preserve soil moisture and keep it available to the main crop as well.
Dutch clover is best suited to undersowing large and/or tall crops with a relatively small “footprint.” Pole beans on a trellis, for example, place almost no “footprint” on the bed. We can sow the clover at the same time we plant the beans. The pole beans grow all season until shut down by frost, and all that time the clover is growing, setting nitrogen, shading the soil and helping retain moisture, and suppressing weed growth. When we remove the bean trellis, we have a bed of fully mature clover that has set a good deal of nitrogen that will be available for a heavy feeding crop the following season.
Other smaller-footprint crops that allow for a successful Dutch clover cover include tomatoes (if trellised), peppers, and broccoli.