“Seed availability, cost, seeding methods, ability to terminate the plants and other factors enter into the number of species a farmer might use,” says David Lamm of the USDA Natural Resources Conservation Service (NRCS).
“Some studies suggest six to eight species from three of the four groups would be about right,” Lamm says. “Our NRCS plant materials centers are conducting a three-year study to look at this.”
Lamm says location dictates the amount of growing season available, so it should be considered when selecting varieties of cover crops.
There are a number of common mixes being recommended depending on the location in the country. For the northern Corn Belt, Lamm says a common mix is cereal rye, hairy vetch, winter peas and daikon radish. In the south and southeastern U.S., a common mix is cereal rye, hairy vetch, crimson clover, and daikon radish.
“But producers shouldn’t limit themselves to these mixes,” Lamm says. “They should continue to experiment to see what might work best on their farms.” He suggests interested farmers talk with farmers who have long-term experience, too.