Plan ahead to plant cover crops for healthy garden soil

By Denise Ruttan

Photo by Chris LaBelle. Nitrogen-rich fava beans make a great cover crop to help build the health and structure of garden soils during the winter.

Think cover crops are just for farmers?

Gardeners can also make use of these inexpensive soil protectors, according to Daniel McGrath, a vegetable crops specialist for the Oregon State University Extension Service.

"Cover crops protect the soil from rain, add organic matter to the soil and in some cases add nitrogen to the soil to help plants grow," McGrath said.

Gardeners who are trying cover crops for the first time should avoid species that have tough, fibrous root systems, such as grains or annual ryegrass.

McGrath recommends three easy-to-grow winter cover crops: fava beans, bell beans or Austrian winter pea. Most nurseries and garden centers sell seeds of all three.   

In August, remove all crop residue and weeds, as well as loosen the soil with a garden fork, advises McGrath. Plant winter cover crops between Aug. 15 and Sept. 15, and they should be growing by mid-October, when the rains normally start.

When cover crops reach about 2-3 feet tall the following spring, mow them to the ground or cut off all the vegetation above ground and add it to your compost pile. Use a garden fork or a square spade to chop up the soil and cover crop roots. Thoroughly mix the cover crop roots with the soil and let the roots decompose before planting your spring and summer vegetable crop. Wait about 3-4 weeks after turning in the cover crop roots before planting summer vegetables.

Gardeners can also grow certain cover crop species in the summer. McGrath recommends experimenting with the summer cover crop known as "buckwheat.” Prepare the garden bed as if you were going to plant a summer vegetable crop and sow buckwheat instead.

Later in the summer, just as the buckwheat begins to flower, mow it to the ground or cut off all vegetation above the soil and toss it in your compost pile.

Thoroughly mix the cover crop roots with the soil and let the roots decompose before planting your fall vegetable crop. Wait about 3-4 weeks after turning before planting again.

To learn more about cover crops, see the Extension guide "Cover Crops for Home Gardens" at http://bit.ly/ href="http://bit.ly/OSU_CoverCrops">http://bit.ly/OSU_CoverCrops.