Put Your Garden to Sleep with a Cover of Green
Elizabeth Anne Wuerslin
Colorado State University Extension Master Gardener in Larimer County
October 31, 2009
Late this summer, my raised bed garden was simply worn out. After wet spring rains and then beating hail, it was tired. Weeds were becoming bolder, and I was exhausted at the thought of planting a second crop of cool weather vegetables. That is when I decided to let nature do the work and plant a blanket of winter rye, a cover crop of what is also known as “green manure.”
Cover crops are plants grown not to be used as food, but as plant material which is used to improve soil conditions. They can be cut down and dug into the soil in the spring. Cover crops improve soil by adding organic materials, replenishing soil nutrients, building soil integrity or tilth, and reducing erosion. They also reduce the need for nitrogen fertilization. Best yet, these crops keep weeds down as well.
Cover crops are usually grass varieties or winter legumes. Winter rye, buckwheat, annual rye and oats are some of the most common grasses. Winter rye grass is a good choice for Colorado gardens as it tolerates poor soils and does not need much rain. Winter legumes are great nitrogen recyclers, and include crimson clover, winter peas, and hairy vetch. The latter legume has been especially bred for colder climates. Some gardeners combine grasses with legumes, i.e. winter rye with hairy vetch, to create diversity. The roots of the grain protect the slower growing vetch.
Seed winter rye and Austrian pea at 4 to 6 ounces per 100 square feet. Two to 3 ounces of hairy vetch is needed for each 100 square feet of garden area. Note that these green winter plants are attractive to deer and geese. If they are well established prior to extreme winter temperatures, plants generally recover from winter grazing in spring.
Come spring, my winter rye will be cut down and dug in. I plan to let the residue sit for about three weeks before planting my spring crops. In the meantime, I will read garden catalogues, rest and let the sun and soil do their thing.
Refer to Plant Talk 1607, “Cover Crops: Winter Rye.”
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