Cover crops are an essential component of every sustainable farm. They are an investment in your gardens and fields that will pay future dividends of healthier, more productive cash crops.
The benefits of cover cropping are numerous and impressive:
- Cover crops increase soil fertility. Annual legumes such as soybeans and cowpeas can be grown in rotation over several years in vegetable fields. Perennial legumes such as clovers can be maintained for several years on fields that aren't needed for cash crops. Legumes fix nitrogen while they're growing, and add organic matter when incorporated into the soil. Cover crops used for this purpose are referred to as "green manures."
- Cover crops prevent soil erosion in winter by keeping the soil covered. A mixture of oats and winter rye, for example, can be planted in fall. The oats will be killed by cold weather, but their root systems will hold the soil in place. Winter rye will form small plants that will grow rapidly in early spring, to be mowed and tilled in before planting the field the following summer.
- Cover crops prevent weeds from flourishing on bare soil, in which case they are known as "smother crops." Fast-growing annuals such as buckwheat or soybeans can be planted after a crop is harvested to outcompete weeds. They also can be underseeded with taller cash crops or between rows to cover the soil and prevent weed growth.
- Cover crops can be planted as a "catch crop" after a vegetable crop is harvested to use nutrients that might otherwise leach into groundwater.
- Cover crops improve soil tilth. Besides adding organic matter when tilled in, the roots of actively growing cover crops loosen and aerate soil. Deep-rooted cover crops such as sweet clover will help break up hardpan layers several feet deep. Several cover crops can be grown to be cut for hay or straw, to feed livestock or mulch horticultural crops.
Lynn and her family have been growing vegetables and cut flowers since 1988, selling through CSAs, at farmers' markets, to chefs, grocery stores, and florists. They currently grow cut flowers and hoophouse tomatoes on about 2 acres of their 20-acre farm near Lawrence, Kansas. She is also the author/editor of The Flower Farmer.