Hi, I live in North York in Toronto and would like to enrich my backyard vegetable garden soil prior to planting tomatoes, leafy greens, zucchini, beans and herbs. Which cover crop would be best suited and would grow quickly enough prior to the May planting period?
Thank you for your enquiry about using cover crops in your urban vegetable garden.
Cover crops have been used by farmers all over the world to enhance the soil and improve their crops. More and more urban vegetable gardeners such as you are realizing the value of using cover crops even in their smaller backyard gardens.
A cover crop is vegetation that is sown most frequently in the fall, killed off in the spring and then the biomass is incorporated into the soil before vegetables are planted.
Cover crops are divided into 4 groups: grasses (rye, barley), legumes (alfalfa, clover), brassicas (radishes, turnips) and non-legume broadleaves (spinach, flax). Each group has a slightly different affect on the soil but in general cover crops prevent erosion of soil nutrients, reduce weeds, enhance soil structure to improve nutrient and water retention, add organic matter to the soil, and perhaps most importantly, they fix atmospheric nitrogen which can then be used to feed the soil and then the plant. Heavy feeders such as tomatoes benefit greatly from this natural process. The longer the growing season, the greater the nitrogen fixation.
Cover crops should be applied every year to ensure a longer term benefit for the soil and vegetable growth.
You will be seeding your cover crop this spring. Red clover will provide a good quantity of nitrogen and biomass to your soil. It can be sown in the spring between your rows of vegetables. After your fall harvest, you will want to sow red clover over your entire vegetable bed and incorporate it into your soil in the spring.
Please remember to continue to add organic compost to your vegetable garden every year, even though the soil is benefiting from the nutrients of the cover crop.
Below are a few web sites that provide more in depth information about cover crops that you might find interesting. https://www.cropnutrition.com/cover-crops-type-makes-a-difference
https://organicgrowersschool.org/gardeners/library/basics-of-cover-cropping/ This web site has a useful chart listing different cover crops and their benefits.