Planting Cover Crops to Improve your Garden

Ask Miss Jean!


Jean Lovell, long-time Resource Central volunteer and former master gardener, tackles your gardening questions!

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Q: What are cover crops and why should I plant them?

A: Cover crops, often called “living mulch” or “green manure” are plants that are grown to benefit and or/protect the soil. For home gardens, the most important benefits are improving soil structure and increasing organic matter. Other benefits include disease and pest control, weed suppression, and decreased need for chemical fertilizers. Legumes “fix” nitrogen – convert nitrogen in the soil and the atmosphere into a form usable to plants. Nitrogen is essential for growth of all living things and in the production of proteins and other chemicals.

– A mixture of legume and non-legume cover crops is most beneficial. Non-legume crops help with organic matter and soil structure. Legumes add organic matter and fix nitrogen.
For winter coverage: common crops include winter wheat or winter rye, (note that ‘rye grass’ is something entirely different). Legumes include clover, hairy vetch, and field peas.
For summer coverage: buckwheat and most any annual grasses combined with annual clovers.

– Some seeds are available in bulk bins at natural food stores. For others, check:
Arkansas Valley Seed, Denver
Pawnee Buttes Seed, Greeley
Poudre Valley Coop, Fort Collins
Buffalo Brand Seed, Greeley, mail-order site of Peaceful Valley Farm Supply

– Cover crops can be planted at several times of year; usually they are grown in the “off-season”. Rotating crops throughout the year and over several years gradually improves the soil and leads to better tasting crops. To start the process, in mid to late October, after a killing frost, turn over dead food plants and sow seeds thickly to prevent weeds. If they flower, mow them to prevent self-seeding and excessive growth. In spring, turn over the cover crop; if you use fertilizer, add it; and transplant or seed your food crops. If the cover crop didn’t die, wait until about 2 weeks after you turn it over before seeding or transplanting.
– In new garden beds in spring or early summer, plant one or two crops of buckwheat or beans to improve the soil and choke out weeds.
– Summer cover crops are often used in empty spaces to suppress weeds.
– With established flower and veggie gardens green manure planted early helps improve the soil; then after turning the soil, plant warm-season veggies or bedding plants.
– A cover crop planted after harvesting early-maturing veggies will add organic matter and help prevent weeds.

– When the cover crop is established, dispose of any remaining seedheads by:
     – Mowing it down, allowing it to dry and then tilling the soil OR
      – Leaving it on the soil as a mulch layer
– For more information on getting your garden ready to plant after your cover crop visit this article by Grow Organic