Cover crops help gardens

If you are looking to boost the quality of garden soil on your acreage this summer, try planting a cover crop. One benefit of cover crops, says Purdue University Extension, is that foliage and root growth can be tilled under in late winter to help loosen heavy soils and to improve overall soil structure and fertility.

Also known as green manure, cover crops can be very valuable in preparing a new site for gardening or for rehabilitating a heavy or compacted site. Many gardeners also plant cover crops to help keep their soil from blowing away over the winter.

Plant in late summer/early fall

Cover crops are generally sown in late summer or early fall. In established gardens, wait until after summer vegetables are harvested.

The type of crop to grow will depend on the desired function and availability. Winter rye, buckwheat, hairy vetch, and winter wheat are ideal for use as cover crops. They are also among the most commonly available cover crops through home garden centers and mail-order catalogs.

The amount of seed to plant will vary with the species, but in general, winter cover crops are seeded at a rate of 2 to 3 pounds per 1,000 square feet. Till or spade the soil. Scatter the seed over the area, and then cover at a depth corresponding to the size of the seed.

Large seeds should be covered with ¼ to ½ inch of soil or compost. Small seeds can be left on the surface and lightly raked. Apply a thin layer of loose straw to protect the area from wind and runoff from heavy rains.

Fertilizing is generally not necessary, especially for established garden beds. Some members of the legume family of plants, most notably alfalfa and hairy vetch, actually facilitate the fixing of nitrogen in association with certain soil-borne bacteria. The bacteria colonize in nodules of the legume's roots.

Other benefits of cover crops

The root growth of the cover crops will help loosen heavy or otherwise compacted soils. The addition of the dead foliage later in winter or spring improves aeration, water-holding capacity, and nutrient status.

Plow the cover crop under several weeks prior to spring planting time to allow the vegetation a chance to break down a bit. For plants that have a large volume of top growth that tends to get tangled in the tiller tines, mow the tops first, then till under.