How and why I use cover crops in my garden.
I like to take chances. As co-owner I wear a lot of hats at Botanical Interests but one of the most exciting ones for me is when I can be creative with new products. Several years ago, we added a few cover crops in garden-sized seed packets hoping that gardeners would take advantage of this long-time, organic, agricultural-scale practice in their small plots. The response makes my heart sing! Not only did the packets sell, they also have created so many conversations with customers wanting to know more!
Cover crops or “green manures” have gone hand in hand with agricultural practices for a long time and were even documented by the Roman poet, Virgil, in 29BC. Cover crops naturally re-enrich soil, protect it from erosion due to rain or wind, improve its texture, and feed soil organisms which maintain a healthy ecosystem in the soil. As gardeners, our success is directly tied to the soil in a very tangible way, but looking at the bigger picture, soil health impacts all its inhabitants.
“History is largely a record of human struggle to wrest the land from nature, because man relies for sustenance on the products of the soil. So direct, is the relationship between soil erosion, the productivity of the land, and the prosperity of people, that the history of mankind, to a considerable degree at least, may be interpreted in terms of the soil and what has happened to it as the result of human use.” – Hugh H. Bennett and W.C. Lowdermilk, 1930s
Can you tell I am passionate about soil yet?
Our current cover crop selection gives options for spring, summer, and fall cover crop growing. Any of the cover crops you choose to grow and turn into the bed will contribute organic material just due to their vegetation decomposing, and they will also work to stifle annual weeds by shading them out. Oats (peas and oats) and buckwheat, however, are “allelopathic”, meaning they naturally exude chemicals that prevent weeds from growing. The magic in this is that when weed seeds begin to germinate the allelopathic chemical stifles the new roots as they emerge which reduces the weed seeds in your soil. Leguminous cover crops like peas and oats (spring or fall but best in fall), fava beans (spring or fall) or crimson clover (spring or fall) fix nitrogen from the air, trapping it in their roots for the next plants to use. Nitrogen contributes to the green growth of plants and is the nutrient we need to add most often in the garden because it is a gas and moves about. Buckwheat (late spring through summer possibly fall, thrives in warm weather) is excellent at mining the soil for phosphorus, which contributes to root, flower, and fruit growth, which it then releases to plants as it decomposes.
Here is how I use cover crops. In spring I sow crimson clover under my fruit trees to enrich the soil and call in the pollinators, and as a bonus, it is adorable!In July, after harvesting my garlic, I sow buckwheat over the bed, chopping it down once I see about a third of it in flower (I don’t want it to reseed) allowing it to regrow. I cut the buckwheat two or three times, letting the cut parts lie on the soil as a mulch, until I turn them in later. Late in summer when my sweet corn or other warm-season crops are done, I sow fava or peas and oats in their place to enrich the soil. A heavy frost will kill the peas and oats, but favas will keep going until it gets persistently cold (below 20°F). I let the dead vegetation stand until spring; the roots hold the soil in place, shade the soil which preserves moisture, and feed microorganisms over winter. I have even used cover crops in newly created beds, giving them some nutrition and keeping the weeds at bay while I decide what to sow. A healthy soil is a soil covered in something living. With few exceptions, a bare patch of soil will quickly be covered with vegetation which nurtures and protects it. Gardening with cover crops is a way we can pick beneficial plants to cover that bare patch.
“The soil is the great connector of our lives, the source and destination of all.” – Wendell Berry, The Unsettling of America, 1977
Read more information on cover crops and how to choose the right cover crop for your organic gardening goals in our article, Cover Crops for a Naturally Better Garden.
Have you been using cover crops in your garden? Share your insight and experience in the comments below!