At the end of the growing season, most vegetable gardeners remove all the dying bean vines and tomato plants. The debris is placed onto the compost pile and creates nutrient-rich compost for next year. Over winter the garden beds are left empty except for some opportunist weeds that tolerate cooler weather. Perennial and shrub beds are covered with mulch to help protect the soil. But vegetable beds are left to the elements where they are subject to rain, wind and freezing which sometimes sends the soil from well-filled raised beds over the side. This is where the cover crop idea helps.
What are the Benefits of Cover Crops?
Cover crops aren’t intended as a harvest for the dinner table. Instead, they protect the soil surface as a living mulch, in a similar way to regular mulch. Cover crops stop weeds and protect the soil surface from erosion.
Cover Crops are Not a New Idea
Organic farmers have used cover crops for decades but only recently has the market responded to the need of home gardeners. Seed suppliers are now putting together a mix of seeds in smaller quantities, which allows the gardener to plant several raised beds with one packet.
How Does a Cover Crop Work?
The idea is that the cover crop is sown late in summer or early fall, depending on your location and winter, and it germinates quickly. This gives a mass of seedlings to cover the bed and stop weed seeds from reaching the surface. In areas of heavy clay soil, the deep roots of some cover crops help break up the subsoil making it more suitable for spring seedlings.
Note: Cover crops are useful for covering the bare ground at any time of the year, but for home gardeners, protection in winter is the most useful time.
Types of Cover Crops
Most cover crops are from the legume or grass groups. They’re varieties that enjoy cool weather like annual clover, winter peas, buckwheat, or rye grass. Radishes can also be used if thickly sown. Radishes are quick to sprout and break up the subsoil as the radish grows. These fast-growing plants often survive light frosts and early snow showers.
How to Use Cover Crops
All cover crops are sown densely so that when they germinate, they cover the soil and slow any erosion. The crop is not harvested when the plants die because they continue to protect the surface of the soil through winter weather. In spring, the now dead plants keep the surface covered until you want to plant early crops. At this stage, the cover crop is dug into the garden bed.
After turning the cover crop into the soil by digging it in you add organic matter to the soil as the plants and roots decompose. The nutrients from the cover crop are then released into the soil just as it does in the compost heap. The legumes are popular cover crops because they fix nitrogen in the root nodules and this too enriches the soil.
Bonus: Clovers and grasses make the garden beds much more attractive than being bare through winter too!
If you’re interested in learning more about soil health and the different soils available at garden centers, then you’ll love our article The Dirt on Garden Soils.