Grow Your Soil with Fall Cover Crops

From left: blossoming arugula and miners’ lettuce (photos by Joshua Burman Thayer)

September Gardener’s Notebook by Joshua Burman Thayer

Once those winter rains come, the daily pummeling of raindrops can do a number on your soil, which is why some people put their gardens to bed through the winter with a two- to four-inch-thick layer of mulch. You can use straw hay, wood chips, cocoa hulls, or even simply fallen leaves (Avoid eucalyptus and sycamore leaves, however, as they are known to spread disease.) Mulch helps feed the soil as the force of driving rains help decompose the material, breaking it down to finer particles, which help build the fertility of the soil.

That’s all well and good, but why not grow some cover crops instead? Here in the subtropical East Bay, where there is little-to-no frost and a bounty of 300 or more growing days per year, there’s no reason not to try growing your soil through the winter with a diverse soil-building mix of cover crops, all of which can provide nutritious food for your table.

Cover crops help your soil in at least four ways:

  • They feed the soil with nitrogen and micronutrients
  • They create more fluffy soil tilth with decomposing cover-crop plant residues
  • They support local pollinators that appreciate the cover crops’ blossoms when sources of nectar become scarce in winter
  • They protect the soil from the compaction of raindrops.


Fava bean pods and flowers (photos by Nicki Rosario)


Here’s a selection of cover crops to plant now. All are edible and all can be direct sown from seed right into the soil. 

Miner’s lettuce: (claytonia spp.): This easy-to-grow native plant can infill under your orchard canopy and provide salad by the yard! (Read my past article on miner’s lettuce here.)

Fava beans (vicia faba): An Italian staple, fava creates copious and attractive biomass during the wet season. Its flowers are lovely, and the tender greens are edible. Plus, you’ll have a harvest of beans later in the season.

Sugar snap peas (pisum sativa): Set up these vines to grow vertically on the borders of your beds, and come spring, you’ll have lots of tender edible-pod peas to snack on or add to stir-fries.

Snow peas (pisum sativa saccharatum): Similar to sugar snaps, but the edible pods are flatter.

Arugula (eruca sativa): A salad favorite, arugula is super-easy to grow. (Read my full article on arugula here.)  

Radish (raphanus sativus): A quick and easy 30-day crop.

Parsley (petroselinum crispum): This aromatic plant provides greens for humans and helps dissuade pests.


Bonus tip: Use Tree Collards as a Trellis

Not a cover crop, tree collards are a perennial that you can plant in September. By late-October, as they reach two feet tall, they can serve as trellises for your climbing sugar snap peas. The peas will sprout and wind their way up the stalk without hurting the tree collards. In general, brassicas like tree collards tolerate bio-intensive production and won’t get sick just because other leaves are touching their surfaces.


To Learn more about Food Forests and Permaculture Landscape Design, visit Joshua Burman Thayer at Or call 510.332.2809.