Cover Crops

The educational materials listed on this page are about Cover Crops.

What is a cover crop? A common definition of a cover crop is a plant that is used as part of a crop rotation to improve the soil, scavenge or add nutrients, smother weeds and as a tool for erosion control. Cover crops are not harvested, but are left in place in no-till farming or turned under, especially in organic farming. Another term for cover crops is green manures, especially when the crop residue is incorporated into the soil.

Cover crops can improve soil fertility by adding organic matter, and they help in nutrient management planning by adding nitrogen to soil or by taking up nutrients in soil after cash crop harvest. Winter cover crops are most common in corn and soybean grain production systems, while spring cover crops or summer cover crops can fit many vegetable production systems. Cover crops improve soil moisture, especially over time as soil organic matter and soil tilth are improved.

Cover crop cocktails are used by many farmers as a way to improve soil health. Cocktails or cover crop mixes usually include a grass cover crop such as cereal rye or annual ryegrass, a legume cover crop like crimson clover or hairy vetch, and sometimes a brassica cover crop like forage radish, sometimes called “tillage radish.” Cover crop benefits from cocktails are often greater than seeding a single cover crop species. Cover crop mixes contribute to pest control by attracting beneficial insects and they may increase weed control by providing more ground cover and leaving more crop residue on the soil surface. Some cover crops can mitigate plant disease by suppression soil pathogens. Cover crop cocktails also attract pollinators, including native pollinators.

Cover crop seed is increasingly available from seed companies. They may also be able to help you with information about cover crop selection as well as best timing and methods of planting cover crops.

Some SARE books will help you decide how and when to grow cover crops. Managing Cover Crops Profitably, Crop Rotation on Organic Farms, and Building Soils for Better Crops are comprehensive guides or manuals. Another useful resource is the SARE topic brief Cover Crops for Sustainable Crop Rotations, which summarizes the usefulness of rotating cover crops in any cropping system. For organic farming, see the Organic Transitions business planning guide.