›› Alysha Punnett
Cover crops provide the same benefits as other mulches like straw, but are extra beneficial because they are living (see our Factsheet #7). The active root zone of the plant cycles nutrients and minerals, keeping them in the planting zone of your soil instead of washing away with the winter rains. The roots also continue to interact with microorganisms, maintaining soil life even when it slows down in cold weather. Above ground, the greens of these plants protect the soil from the elements. In my experience, all of this leads to a nutrient-rich soil with a beautiful texture.
When to Sow
Seed cover crop September through October. You want at least a few inches of green before the cold hits and growth slows down. As the weather warms, growth will speed up and you can expect many more inches before flowers start to appear.
How to Cover Crop in the Backyard Garden
Cover crops are often grown on farms in between cash crops, then tilled in with farm equipment so the nutrients enrich the soil for subsequent crops to feed from. Many of us are low-tech backyard gardeners and using a rototiller isn’t realistic. In our case, cover crops become compost fodder as well as soil conditioner because of the volume of green material that is produced (i.e. it’s a big job to hand-dig in all of the cover crop). In the spring, as the first flowers appear on the cover crop, chop the tops and use them in your compost pile. Roughly chop up the roots in the soil using a shovel and allow them to decompose for around two weeks, releasing all their nutrients back into the soil for your spring planting. You may need to rake through and compost the dried up roots before planting, but this is great compost food too.
Cover Crops for Backyard Gardeners
Cover crops that I find manageable with a shovel and my muscles are crimson clover, winter field pea, fava beans and buckwheat. With all of these, make sure to spread bird netting over the seeded area until germination occurs, or the birds will be thanking you for a hearty meal.
Check out compost.bc.ca for more factsheets and our shiny new workshop line-up!