A Diverse Winter Cover Crop

Benjamin Eichorn
Benjamin is an internationally renowned expert on the topics of edible gardening and food literacy education. He is the author of “Edible Gardening: Ten Essential Practices for Growing Your Own Food,” and is the Founder and CEO of Grow Your Lunch (www.growyourlunch.com). He is based in San Francisco, CA. Benjamin taught in the Edible Schoolyard Berkeley garden from 2006 to 2010.

The basic idea of cover-cropping is to sow seed over ground that would otherwise be bare in the garden or on the farm. Cover crops are often grown throughout the winter in temperate latitudes, however there are appropriate seed mixes for any time of year.

Among the myriad reasons for cover cropping, erosion control, nitrogen fixation, and the development of organic matter are the most widely recognized. Some cover crops can increase habitat for beneficials such as pollinators and predatory insects, others can serve as “trap crops,” luring pests away from your other crops. Plants with a long taproot such as radishes and mustards can even help break up hardpan clay soils!

Even weeds can serve as effective cover crops. The most relevant aspect to managing weeds as cover crops is understanding their reproductive cycle. If the weed in question is a perennial and can spread without the production of seeds, it should probably not be used as a cover crop. For most annual weeds, however, merely ensuring that they are tilled in, harvested, composted or “chopped and dropped” as mulch before they produce mature seed is enough in the way of management. A diverse, even weedy, winter garden ensures a diverse and abundant soil food web and healthier and more vigorous fruits and vegetables in the coming seasons!

Our favorite cover crop mixes are improvised. A mixture of grains and legumes is a good base for your seed mix, but they alone they are not sufficient. Grains have complex root systems, which provide erosion control, and legumes fix atmospheric Nitrogen in the soil with the help of Mycorrhizal bacteria.  

Instead of growing a plain mix of grains and legumes, try throwing all your old seed into your mix and see what comes up!  In many cases you can begin to grow your weeds of choice. Our favorite “intended weed” is arugula. Even late into the Winter growing season in the San Francisco Bay Area, we will sow arugula, radishes, flax, cilantro and parsley and low-growing native wildflowers around our Winter lettuces, broccoli, fennel bulb, celery, chard, kale, chard, onions and garlic. We’ll even sprinkle in some Cupani sweet peas and see where they come up. At Grow Your Lunch, we believe that reckless and spontaneous growth in the Winter garden is the most beautiful.

Our inspiration for a diverse winter cover crop is in great part inspired by Masanobu Fukuoka, Japanese pioneer in sustainable agriculture, who demonstrated the art of “no-till” farming. He managed large production vegetable fields without tillage by sowing and harvesting all year round. By balling up a mixture of his seeds in clay and tossing these balls into the field at the proper time of year, he ensured both a diverse habitat for wildlife and minimal intrusion into the fragile soil.

If you don’t have a chance to cover crop this winter, try sowing a diverse cover in a plot that is lying fallow or one that has been opened but won’t be planted for a few weeks in the late spring or early summer. Even letting a cover crop “flush” or grow for 6-8 weeks can be enough to substantially increase the organic matter. Additionally, consider sowing a low growing mix under your Summer vegetables in order to control weeds and encourage the productivity of a more diverse ecological community.

Good luck and happy gardening in the new year! If you’d like more tips about when to cut down or “turn in” your cover crop, read more here.



This post is republished from the Grow Your Lunch blog. For more from Benjamin Eichorn, visit growyourlunch.com or download his handbook Edible Gardening: 10 Essential Practices for Growing Your Own Food.