Published on 09/06/07

Plant cover crop in garden spot

By Sharon Omahen
University of Georgia

If the thought of planting a fall garden in the middle of a drought makes you fret, it may be time to take a rest and give your garden one, too.

"One option gardeners have is to plant a cover crop instead of a winter vegetable garden this fall," said Bob Westerfield, a Cooperative Extension horticulturist with the University of Georgia College of Agricultural and Environmental Sciences.

The term cover crop comes from the act of using plants, or "green mulch," to protect the soil from erosion, he said. Cover crops also release rich nutrients into the soil.

Grains and legumes

There are several choices when you select a cover crop. Westerfield recommends a combination of an annual grass or grain crop and a legume.

"An excellent choice would be a mixture of wheat or oats and clover," he said. "Small grains are easy to grow and germinate quickly and will act as a nurse crop for the slower-germinating clover."

Legumes such as clover or winter peas produce nitrogen-fixing nodules in their root systems, Westerfield said. These nutrients will be valuable to your garden when you till in the cover crop next spring.

Plant when soil cools

The ideal time to plant a cover crop, he said, is after soil temperatures cool down between late September and early October.

If you decide to plant clover, be sure the seeds have been inoculated before you plant them.

"Inoculation basically means adding a small packet of powdered bacteria that helps disintegrate the seed coat and aids in germination," he said. "Most feed stores that carry clover and other legume seed will either sell the inoculants or sell preinoculated seed."

Before planting a cover crop, first remove all residues from this year's garden. Then till the soil thoroughly.

Mix wheat and clover seed together and broadcast the mixture across the entire garden. Use a light rake or drag across the seed bed to ensure good seed-to-soil contact.

Plant shallow, water well

"Be careful not to bury the seeds too deeply," Westerfield said. "If you do, your seed germination will be greatly reduced."

Water the garden early on to promote seed germination. Then water as needed when it doesn't rain. Winter rains should provide future irrigation for your cover crop.

To decide whether you need to fertilize your cover crop, take a soil sample to your county UGA Extension office. Usually, Westerfield said, all you need to establish a good cover crop mixture is to fertilize once when you plant.

In February or March, if you want to plant early-season crops such as lettuce, onions, carrots or beans, till under a few rows of your now fully established cover crop. Wait a few weeks to let the debris decompose before you plant.

You can use the same method to plant your spring garden. Mow and till under rows of the cover crop to reveal your planting rows. Leave the remaining crop to protect the soil and block out weeds.

If you prefer to start with a clean garden slate, mow and till in the remaining cover crop when you're ready to plant your entire spring garden.

"The best thing about planting cover crops is they're pest-free and maintenance-free," Westerfield said. "Your cover crop gives a bright, green contrast when everything else may be dormant. And the clover produces an attractive display of flowers in the spring."

Sharon Omahen is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.