Tips for Planting Cover Crops in Home Gardens

"Soil is meant to be covered." Think about it! What happens to a bare patch of soil? In a very short time, plants will cover that bare patch. Unless we guide Mother Nature, those plants may be weeds. What an awful thing to happen to our well-tended gardens during the off-season! 

Why would you use your valuable time and money to add another crop to your garden? Cover crops planted in late summer or early fall are an inexpensive way to build better soil for gardening. Cover crops are often called green manure crops. They are grains, grasses, brassicas, or legumes that will grow during fall and winter and that you can plow, spade, or till under in the spring. During their growth, cover crops help reduce soil compaction, capture excess nutrients, and prevent erosion. Their roots penetrate and help loosen heavy-textured soils, allowing better air and water penetration. Legume cover crops add nitrogen to the soil. When you turn cover crops under, they add organic matter to the soil — building better soil structure and fertility. All gardens need organic matter to maintain the bacteria, fungi, earthworms, and other life forms needed to make healthy, fertile soil.

One does not need to plant a cover crop all at one time. My father planted annual ryegrass as each crop finished from early August through October. The garden began as a patchwork quilt that became lush green before winter. Annual ryegrass has an extensive root system that occupies the same root zone as the garden plants. Winter rye is a good choice for planting as late as early November since it will still germinate as low as 35°F. Its roots are amazingly deep. Because it is winter-hardy, turn it under when it is 10 to 12 inches tall; otherwise, cut it with a scythe or mower before turning it under in the spring.

To plant a cover crop, rake the garden area smooth and remove debris or large stones. Broadcast the seed according to the recommended rates. Lightly rake again and water in the cover crop with your hose set at a fine mist. To get your cover crop off to a good start, add a complete fertilizer like 10-10-10 at 10 pounds per 1000 square feet. If you are planting legumes, use a lower nitrogen fertilizer, such as 5-10-10.

In the spring, as soon as the ground dries enough, turn under the cover crop. To allow time for the organic matter to decompose, turn under at least two to three weeks before planting the garden. Do not allow cover crops to go to seed, or they may become unwelcome weeds. Cut down the plants when or just before they flower. You carefully watch your summer crop for success — be sure to watch your cover crop, so it is successful, too.

Seed cover crops as early in the growing season as possible for good establishment. Plant annual ryegrass from August through October at a rate of 1 to 2 pounds per 1000 square feet. Plant oats until September, wheat until October, and winter rye until November, all at a rate of 4 pounds per 1000 square feet. Plant brassicas, including tillage radishes, turnips, and rapeseed, in August at a rate of 1 pound per 1000 square feet. Plant alfalfas and clovers in August or September at a rate of 1 to 2 pounds per 1000 square feet. Purchase your cover crop seeds at a local garden center, farm store, or online using their application rate chart.

As you decide what to plant as a cover crop, please remember that brassicas (mustard and cabbage family) get off to a fast start in August and provide excellent weed suppression. However, they may develop a rotten egg-like odor as they decompose. Is your home or a neighbor’s home downwind during winter thaws?  Also, do consider how attractive the cover crop may be to wildlife. Legumes (bean and clover family) will draw in deer. I once considered planting a cover crop of beautiful crimson clover along my stone wall. Fortunately, I remembered that this seed is common in food plot blends for deer. What may be suitable for a garden in town may not be for a country garden and vice versa! Experiment with cover crops, just as you do with your garden's plants. Keep notes on a calendar or in a journal because you may not remember accurately. Do not forget that soil is meant to be covered!

For more information see Improve Vegetable Garden Soil with Cover Crops.