Cover crops are fast-growing small grains, grasses or legumes that are generally planted in the fall and tilled under in the spring.
Cover crops are used to increase the amount of organic matter in the soil, prevent erosion, fix nitrogen in the soil, reduce the number of weeds in the garden and provide habitat for beneficial insects. Your choice of cover crops will depend on the results you want to achieve in your garden.
Cover crops that are tilled in to improve the soil are sometimes referred to as green manure. Legumes such as dwarf white clover, crimson clover, and hairy vetch or bell beans will fix nitrogen in the soil while adding organic matter when they are tilled under in the spring.
When fast-growing winter rye is planted in the fall, it quickly covers the ground and crowds out weeds. The roots survive winter cold and the plants begin to grow early in the spring before early weeds have a chance to become established.
Tilling under the rye in the spring will increase the organic matter in the soil and leave the garden bed with fewer weeds and ready for planting about three weeks after it is tilled in.
Buckwheat is a cover crop that is planted in summer. Plant buckwheat where an early vegetable crop has already been harvested, or in a spot that has become overwhelmed by weeds. Start by tilling the soil and then broadcast seeds. The seeds will quickly germinate and prevent weeds from taking over again. Till under a buckwheat cover crop before the plants go to seed. Buckwheat grows and flowers in only six weeks and it also adds calcium, phosphorus and potassium to the soil.
Cover crops with blossoms, such as hairy vetch, crimson clover or buckwheat will attract beneficial insects to the garden where they will help pollinate your plants and attack damaging insects.
Leaving bare soil in the garden is an open invitation for weeds to come in, but planting a cover crop will help make your garden a private party for your plants.