Cover crops need 30-40 days of good growth before the first hard frost. Seeding after harvest will normally not allow cover crops to grow large enough to survive the winter. Seed from the end of August until mid-September. Cover crops may be air seeded prior to harvesting soybeans and other crops, or seeded conventionally after silage harvest. Many crops can be used for cover crops.
Cereal rye is common.
Kill cover crops in the spring. Mowing or herbicide application is acceptable. Tillage is not recommended because it will bury residue. Early kill is important to reduce the risk of depleting moisture needed for the grain crop. Legume cover crops add nitrogen to the soil, providing a low-cost fertilizer for grain crops.