Using Cover Crops in the Garden


by Karen Weiland, Advanced Master Gardener



If you would like to increase the amount of organic matter in your garden soil, planting a cover crop would be a good beginning.  Nearly all garden soils need organic matter to  maintain the bacteria, fungi, earthworms and other forms of life needed to make it healthy and fertile.  Cover crops also prevent erosion,  loosen heavy, compacted soil ( better water and air penetration)and improve fertility.

A cover crop, also known as green manure, can be small grains, legumes or grasses and are usually planted late summer to early fall.  Your choice of cover crop should be sown right after the vegetables have been harvested.  They normally require four weeks of growing before cold weather sets in at which time they will stop growing and go dormant.  Before planting a cover crop, vegetable debris should be removed from the garden and the soil will need to be worked with a tiller to the depth of about six inches.  If fall vegetables are still growing in your garden, plant  the cover crops between the rows.   Add some compost or some well-rotted manure at the rate of 20 pounds per 100 square feet or you can also add a complete fertilizer such as 15-15-15 at the rate of one pound per 100 square feet at the time of tillage.

Some of the most commonly available cover crop seeds are winter rye, hairy vetch, winter wheat and buckwheat.  You should be able to find them at your local garden/farm store or by mail-order catalog.

During the summer, continuous crops of buckwheat can be planted where early vegetable crops have been harvested.  Work the soil before broadcasting the buckwheat seed which will germinate quickly and prevent any weeds from becoming King of the Garden.  Buckwheat grows and flowers in only six weeks and needs to be tilled under before it goes to seed.  It adds calcium, phosphorus and potassium to the soil and likes the heat of the summer.

Winter cover crops are usually seeded at a rate of about two to three pounds per 1000 square feet.  Exact coverage will depend upon which one you use.  Work the soil, then scatter the seed at a depth that corresponds with the size of the seed.  Larger seeds should be covered with one fourth to one half inch of soil or compost.  Smaller seeds can be lightly raked in.  It’s a good practice to cover the seeded area with a loose layer of straw to protect it from wind and rain.  If the soil is dry, irrigate often enough to keep the soil damp to germinate the seeds.

A winter-hardy cover crop will resume its growth in the spring.  If needed, keep it mowed so it does not go to seed and then till it under as soon as the soil can be worked.   Mowing down a heavy top growth before tilling it in will make your work a lot easier. Cover crops need to be tilled under two to three weeks before spring planting begins to allow the vegetation a chance to break down a bit.

Give your garden a reason to smile, plant a cover crop.


As always, Happy Gardening!


More information about gardening and related subjects is available online at  The Purdue University Cooperative Extension Service can be reached at 499-6334 in LaGrange Co., 636-2111 in Noble Co., 925-2562 in DeKalb Co. and 668-1000 in Steuben Co.