Why use cover crops?

A cover crop of winter wheat and hairy vetch at the USU Student Organic Farm.

According to the Natural Resource Conservation Service, cover crops are planted to “prevent erosion, improve soil’s physical and biological properties, supply nutrients, suppress weeds, improve the availability of soil water, and break pest cycles along with various other benefits.”

The Conservation Technology Information Center (CTIC) says that cover crops also increase yields. Results from their 2013-2014 survey show that farmers who used cover crops harvested 3.1 percent more corn and 4.3 percent more soybeans per acre than those who didn't. The survey also shows that the number of acres planted in cover crops grew 30 percent each year between the years of 2010-2013, and that it costs farmers an average of $25 per acre for seed to plant them. The CTIC adds that planting leguminous cover crops adds nitrogen to the soil (reducing the need for fertilizer).

Cover crops aren't just for farmers. The Utah State University Extension recommends several ways of using them in gardens: 1) planting half your garden with food crops and the other half with cover crops, and then rotating every year, 2) planting two years of garden followed by a year of cover crops, 3) planting cover crops in the summer after early crops (like lettuce) have been harvested, 4) planting cover crops in the fall to be tilled under in spring, 5) planting strips of cover crops between food crops, and 6) interplanting companion crops (planting strips of fruits and vegetables into already growing cover crops). Rodale's Organic Life also offers an overview of cover crops for gardeners.

How do you know which cover crops are right for you? The Agricultural Resource Service has created a helpful chart (PDF file) for choosing the best cover crops for a variety of circumstances.