What is a good cover crop to plant?


If we want to let our garden be fallow for this summer season what is a good cover crop to plant?


Kate Garland, Horticultural Professional

Very wise of you to make a plan for your resting garden. Buckwheat followed by oats is one of my favorite combinations. Buckwheat grows quickly, out competing many weeds for light and moisture resources, and serves as a food source for pollinators when it’s in flower. Mow it back about 10-15 days after it begins to flower in order to avoid having the seed become a nuisance. Follow with oats, which will put on significant growth for the remainder of the season, but reliably winterkill in Maine; leaving a nice mulch behind the following spring that will further suppress weeds by blocking the light on what would have been bare ground. Find more information on cover crops. Buckwheat and oat seeds are typically available at animal feed stores.

Keep in mind that cover crops are often given more weed suppression credit than they deserve. For example, perennial weeds that spread through rhizomes can readily grow among a healthy stand of cover crop. If that’s what you are facing in your garden, here are some other options to consider when you’re not going to be gardening in an area this summer.

  • Leaves/Straw. Five inches of shredded leaves or straw (not hay) should be a good barrier to keep weeds from germinating and the soil in place. Leaves can be shredded with a mulching mower, leaf shredder, or by carefully using a weed whacker in a plastic bin. Shredded leaves will decompose more readily and stay in place better than unshredded leaves.
  • Opaque plastic, tarps or cardboard. A barrier that doesn’t allow light through will help keep weed seeds from germinating and will prevent light from reaching perennial and spreading weeds. Anchoring these barriers well is key to success, especially in windy sites.
  • Mowing. Knock back any weeds that may creep up along the margins of your garden, potentially adding weed seeds to the soil “seed bank”. Many weed species produce large quantities of seeds that can stay viable for 10-30 years (sometimes longer). Simply cutting back the weeds before they go to seed can have a huge impact on weed pressure in future years.