Cover crops (sometimes called “Green Manure”) can be sown at any time when you are not planning to grow a garden crop in a particular space and want to improve the soil, stop erosion, or reduce weeds. Some cover crops are killed by frost, and some survive the winter. Some add nitrogen to the soil, and some harvest surplus nitrogen, making it available the following season.

The longer cover crops are allowed to grow, the more difficult they will be to kill! Unless you want them to reseed themselves, all cover crops should be cut down or tilled into the soil when flowering begins (if not sooner).

The technique for sowing cover crops is simple: scatter the seeds at the recommended rate over the surface of the soil, and cover them lightly. Water them – and that’s all there is to it! The easiest crops to grow are buckwheat (for a summer cover crop) and winter rye (for a fall cover crop). The seeds are large and easy to handle, and require no inoculants. Buckwheat also attracts pollinators for your summer veggies.

You can sow your own combinations of crops (such as Oats with Peas, or Oats with Clover), or use pre-mixed combos such as “Spring Green” (clover/radish/rye) or “Winter Blanket” (oats/radish). Remember that any time your soil is bare, it runs the risk of eroding or becoming infested with weeds. Cover crops solve both these problems, and the aggressive root systems help break up clay subsoils at the same time.

If you are tilling your cover crop under the ground before planting your spring garden, plan to wait two or three weeks to allow the cover crop to decompose before you plant again. If you are pulling the cover crop out or cutting it down at ground level, you can replant immediately.

There are many kinds of cover crops, and they serve a variety of functions. There is a cover crop for nearly any gardening reason or season. Here are some of the options:

  1. WINTER RYE (also known as Cereal Rye) – Secale cereale is what rye bread comes from, if allowed to mature! But for cover crops, it is planted because it germinates quickly and tolerates very cold temperatures – even when young.

    Seeding rate: 6 pounds per 1000 square feet

  2. WINTER WHEAT – Triticum aestivum grows similarly to Winter Rye, except you’d end up with wheat bread if it matured! Both are generally grown as fall crops and are cut down in early spring.

    Seeding rate: 6 pounds per 1000 square feet

  3. HAIRY VETCH – Vicia villosa needs to be planted in late summer or early fall. It adds nitrogen to the soil (unlike rye or wheat) and can easily be killed with a hoe, so it’s easy to plant over it.

    Seeding rate: 1 pound per 1000 square feet

  4. BUCKWHEAT – Fagopyron esculentum is an ideal summer cover crop; it grows quickly and chokes out weeds. It will bloom in just a few weeks, and attracts pollinators. It is easy to pull up or cut back at the soil.

    Seeding rate: 3 pounds per 1000 square feet

  5. BARLEY – Hordeum vulgare is killed by frost, so it needs to be planted in late summer. The dead plant residue protects the soil during the winter, and you can plant right through it the following year. It “captures” excess nitrogen in the soil, so that it does not leach away.

    Seeding rate: 4 pounds per 1000 square feet

  6. OATS – If Avena sativa is planted in early fall with winter peas, oats will support the peas in the spring and can be cut down in April. The peas give nitrogen to the soil; the oats support the peas.

    Seeding rate: 4 pounds per 1000 square feet

  7. WINTER PEAS – Pisum sativum add nitrogen to the soil, and are also attractive to wildlife and livestock for foraging. Planted in early fall, they can be tilled in or cut down in spring.

    Seeding rate: 2 pounds per 1000 square feet

  8. CLOVERS – Medium Red Clover is a biennial which can be sown spring/summer/early fall. Yellow Blossom Sweet Clover should be planted in spring, and is also biennial. White Dutch Clover is perennial and makes a good path cover, but should not be used to overseed a garden space.

    Seeding rate: ½ pound per 1000 square feet