Cover crops have long been used to reduce soil erosion, add organic matter to improve the soil, and provide some winter and early spring grazing in large fields. But cover crops are also beneficial to the home garden, providing a “green” manure to help keep the soil fertilized. Cover crops are known for their ability to provide moisture-conserving nitrogen for the succeeding crop. Cover crops take up and hold nutrients, especially nitrogen that was not used by the previous crop. Because they remove water from the soil, they may reduce the risk of nutrients and pesticides moving through the soil. Cover crops can reduce weed problems and by providing a mulch to cover the soil surface. Some cover crops also release chemicals that suppress weed growth and may reduce populations of soil-borne plant pathogens.
Wheat, rye, barley, and oats are very effective winter cover crops for large fields. They also can be harvested as forage, straw, or grain, or left in the field to provide mulch and organic matter. When planted early enough in the fall, they provide good winter cover and take up nutrients left in the soil from the summer crop. Each small grain crop has its advantages and disadvantages.
In a small home garden, rye and wheat are the two most used in the Bluegrass Region. Rye can be seeded from August in Bluegrass and eastern Kentucky through mid-November. Rye germinates quickly, grows fast, and provides good winter cover if not planted too late. Early planting is important for soil protection and uptake of nutrients left over from the previous crop. Rye is effective in suppressing weeds. It resumes growth early in the spring and may produce too much top growth if not killed soon enough.