To grow winter rye as a cover crop, spread 1 1/2 to 3 bushes of seed per acre, with the greater amounts spread over rough soil or areas where erosion is possible, and lightly till the seed into the soil. Apply nitrogen-rich fertilizer to the soil if necessary, and maintain moist soil until the seeds germinate. Plant cold-hardy rye anytime before the first frost, and plant other varieties one month before the first expected frost.
When planting rye after harvesting corn or other nitrogen-fertilized crops, do not apply additional fertilizer. Read the instructions on the seed to determine how much seed to plant, as the amount needed varies depending on the species.
Mix rye with another cold-hardy plant, such as crimson clover, to encourage successful growth as the temperatures cool. To improve the soil quality, mix hairy vetch with rye. When seeding small areas, such as garden beds, remove weeds and other vegetation, and loosen the soil to a depth of 3 to 4 inches.
Spread 1 to 4 pounds of the seed per 1,000 feet. Rake over the seeds lightly, and use a sprinkler system to maintain moist soil until the rye germinates. Remove the rye by mowing it down several weeks before the final frost of the season.