Cover Crops For Gardens

A mass planting of crimson clover in bloom, with velvety-red flower clusters atop green foliage.

Crimson clover is a cover crop with showy flowers. Photo: Jon Traunfeld

Updated: August 7, 2026

Farmers around the world grow cover crops to protect and improve the soil between harvests, which in turn increases the yields of their primary crops. Cover crop roots pull up and retain nutrients that might otherwise leach out of the soil. Also known as green manures, cover crops are an excellent tool for home vegetable gardeners, especially where other sources of organic matter (like composted leaves or animal manure) are unavailable.

Cover crops provide several benefits:

reducing soil erosion during the winter (or in any season there is no vegetable crop growing in the planting bed);
improving soil quality by feeding the beneficial soil microbes which build good soil texture and maintain drainage;
adding organic material when the debris is turned-under in the spring;
adding valuable nutrients as they break down.

Clusters of small white flowers on the tips of leafy green plants in a mass planting. — Buckwheat in bloom.
Photo: Miri Talabac, University of Maryland Extension

A dense mixture of three plant types: a tall blue-green grass, a climbing plant with small leaflets and purple flowers, and a shorter red-flowered clover. — A 3-species cover crop mixture of winter rye (grassy leaves), crimson clover (red flowers), and hairy vetch (climbing, with small leaflets and purple flowers). Photo: Jon Traunfeld

A short raised bed with lush green growth of a mix of grasses and pea plants. — A grass and pea cover crop combination in a community garden bed.
Photo: Jon Traunfeld

Several rows of subtle planting mounds in a community garden with a lush cover crop mix of grains and peas. — A cover crop mixture of oats and peas providing a dense living mulch for rows of a vegetable garden in late March.
Photo: Miri Talabac, University of Maryland Extension

How to use cover crops

A person holds an uprooted daikon radish that has a thick root roughly six inches long. — The substantial taproot of forage radish helps to break up compacted or heavy clay soil. Photo: Jon Traunfeld

Most cover crops are planted in late summer or early autumn, at the end of the harvest season for warm-season vegetables. Popular choices include grassy grains like oats, winter rye, and winter wheat, and legumes like crimson clover and hairy vetch. Legume roots partner with special bacteria that convert nitrogen in the air into a plant-usable form. This allows legumes to access and use more nitrogen (a key plant nutrient) than the soil alone can provide. When legume cover crops decompose, they return a lot of nitrogen to the soil, which in turn is a valuable resource for vegetable crops.

Fall-sown cover crops are typically planted in a two-month window, starting in mid-August and ending no later than mid-October. The plants should have enough time to germinate and grow before the first hard frost and short days force them into dormancy. Some cover crops (oats and daikon radish) are killed by cold winter temperatures, but most stay dormant for the winter and resume growth in the spring. Cover crops are mown, flattened, and/or turned into the soil before going to seed, usually in late April or early May.

Buckwheat and Dutch white clover are examples of spring- or summer-sown cover crops typically used to help improve bare soil before planting, or to discourage weed growth and erosion before the main crop is ready for planting.

Steps for planting a fall cover crop

Choose and source the seed

Side-by-side paper bowls holding crimson clover and winter wheat seeds. — Crimson clover (left) and winter wheat (right) illustrate the varied sizes of cover crop seeds.
Photo: Jon Traunfeld

Decide which cover crops to plant. For your first time trying a cover crop (or if you want to be able to plant early spring vegetables), sow oats. Oats are killed by the first hard freeze, leaving a brown decomposing mat in spring.
Purchase seed locally if possible from a farm supply store or garden center. You can also order cover crop seeds from most retail seed companies.
Combine legumes and non-legumes when possible. If you plant a two-species mixture, use about 60% of the recommended amount for each. (For example, instead of sowing the full 4 ounces of each crop type, sow 2.6 ounces of each.)

Prepare the planting bed

To sow a cover crop over an entire bed: Prepare the soil by removing vegetable plants, weeds, and mulch from the summer. Loosen the soil with a garden fork and rake the area smooth.
To sow a cover crop while vegetable crops are still producing: Remove mulch from around plants and rake the area smooth. Your cover crop will get a good start but will not interfere with vegetable plant growth.

Sow the cover crop

Seedling barley (grass) and buckwheat (broadleaf) plants growing in a cover crop mix sown on an empty vegetable bed. — A mixed cover crop of barley and buckwheat seedlings. Photo: Jon Traunfeld

Use the amount of seed listed in the following chart. Broadcast the seed by hand or with a hand-held broadcast seeder, preferably before a rain. Mixing seeds with soil or compost will make it easier to distribute the cover crop seeds evenly by hand.
Gently rake seeds evenly into the soil surface, then lightly walk on the seeds to press them into the soil. (The seed must directly contact soil in order to germinate.)

Cover crop selection chart

Ounces to sow cover a 100-square-foot area for a single-species cover crop. For crop mixtures, use an amount reduced to about 60% of the recommended rate for each species.

The ideal sowing period for fall cover crops is from late summer into fall (August 15 to October 1), although adjustments can be made for crop species, location (Western versus Southern Maryland), and weather forecast.

Cover crops for vegetable gardens
Crop (Botanical name)	Plant Family	Ounces to Sow	Season to Sow	When to Turn Under	Notes
Barley (Hordeum vulgare)	grass (grain)	3 to 4	spring or late summer/ fall	spring	not as hardy as rye; tolerates drought
Buckwheat (Fagopyrum esculentum)	buckwheat	3 to 4	spring or summer	any time	not winter-hardy; grows quickly; will reseed
Crimson clover (Trifolium incarnatum)	legume	1 to 2	spring or late summer/ fall	fall or spring	showy spring blooms
Forage radish (a type of daikon radish; Raphanus sativus variety longipinnatus)	brassica	1 to 2	late summer/fall	spring	wide, deep taproots break up clay soil; all parts are edible; monitor for harlequin bug
Spring oats (Avena sativa)	grass (grain)	3 to 4	spring or late summer/fall	summer spring	not cold-hardy; tolerates low pH (acidic soil)
Winter rye (Secale cereale)	grass (grain)	3 to 4	late summer/fall	spring	very hardy; produces a massive root system that breaks up dense clay soil; can be planted the latest in the fall
Hairy vetch (Vicia villosa)	legume	3 to 4	late summer/fall	spring	very hardy; slow to establish; can become weedy, so till under at bloom before it ripens seed
Winter wheat (Triticum aestivum)	grass (grain)	3 to 4	late summer/fall	spring	produces a massive root system that breaks up dense clay soil; easier to manage and terminate in spring than rye or barley

Short green grass covering two empty vegetable beds in winter. — Winter rye covering empty vegetable beds in January. Photo: Jon Traunfeld

You can jump-start the natural process legumes use to obtain atmospheric nitrogen by purchasing an inoculant with the seed - the Rhizobia species bacteria that will colonize their roots. Coat the legume seeds with the inoculant powder by mixing them together in a bag or bucket before sowing.

A dark brown powder is emptied from a bag onto a pile of cover crop seeds in a bucket. — Bacterial inoculant is poured onto legume seeds before sowing.
Photo: Miri Talabac, University of Maryland Extension

A finger props up one root of a pulled-up legume plant. The root has several small, pale-colored nodules attached to it. — Legume root nodules house beneficial nitrogen-fixing bacteria.
Photo: Miri Talabac, University of Maryland Extension

In most years, forage/daikon radish and spring oats will winter-kill (die out due to the cold), leaving a mat of dead vegetation. The debris can be treated as a mulch (planted through in the spring) or turned-under. Turning-under involves using a garden fork or shovel to flip or partially bury the debris so it begins to compost.

Collapsed, darkened, and withered foliage on radish plants whose tops were killed by freezing temperatures. — Forage radish will often die off over the winter from freezing temperatures. The debris continues to serve as a mulch until it breaks down in spring.
Photo: Jon Traunfeld

Collapsed, withered, brown foliage on a cover crop planting of oats. — Oats are not cold-hardy and die off during the winter when sown in late summer or fall. In spring, any remaining debris can be forked into the soil or raked aside to mulch around new plants.
Photo: Jon Traunfeld

Spring vegetable planting may be delayed somewhat by a cover crop (except for oats and usually daikon radish) since you must allow about 2 weeks for the terminated cover crop plants to break down.

Prepare to plant vegetables: cover crop termination

The cover crop needs to be terminated (killed) when you are ready to plant vegetables. There are several options, including cutting the plants down (such as with a lawn mower, string trimmer, or spade) or smothering them with a tarp to deprive them of light. A combination approach - mowing, then covering the stubble with a tarp - can also be effective.

A densely-planted patch of tall blue-green grass and shorter legumes. The foreground part of the planting has been cut down to ground level. — A cover crop mixture of rye, crimson clover, and hairy vetch ready for terminating. One option is to cut all vegetation down to the ground.
Photo: Jon Traunfeld

A booted foot steps on a metal bar that has a rope handle tied to each end. The bar is held parallel to the ground and pushed onto tall grass to flatten it. — A crimper, used to flatten tall crops without disturbing the soil, can be homemade from a metal fence post and rope handles. Hold the bar parallel to the ground and step on it to flatten the cover crop.
Photo: Jon Traunfeld

Fresh-cut cover crop grass lying on the ground in a variety of fragment sizes. — Mown rye cover crop left to dry out and start decomposing on the soil surface. Photo: Jon Traunfeld

Two eggplant transplants surrounded by the mostly-brown stubble of cover crop stems cut several inches above the ground. — Eggplant transplants surrounded by the stubble of cut cover crop stems. This cover crop was terminated by mowing but not smothered before planting, so scattered regrowth may need to be cut down again.
Photo: Jon Traunfeld

Keep the cover crop debris, which is a valuable source of nutrients and which can serve as a mulch to keep protecting the soil from erosion, evaporation, and weed germination as the vegetable plants establish. The cover crop residue will gradually decompose, adding organic matter to the soil and releasing nutrients that can be used by the vegetable roots. If there is too much material to keep on top of (or fork into) the vegetable bed, it can be added to a compost pile and applied as finished compost later in the season.