Home & Garden Garden 13 Best Examples of Cover Crops for Your Small Farm Cover crops can improve soil and suppress weeds. By Lauren Arcuri Lauren Arcuri Writer Swarthmore College Lauren Arcuri is a freelance writer and an experienced small farmer based in rural Vermont. Learn about our editorial process Updated August 5, 2022 Fact checked by Betsy Petrick Fact checked by Betsy Petrick Ohio Wesleyan University Brandeis University Northeastern University Betsy Petrick is an experienced researcher, writer, and producer. Learn about our fact checking process Treehugger / Hilary Allison Share Twitter Pinterest Email Garden Urban Farms Planting Guides Indoor Gardening Insects Cover crops are plants that are grown to suppress weeds, help build and improve soil, and control diseases and pests. They're sometimes called "green manure" or "living mulch," since they can add nitrogen to your soil and boost fertility without using chemical fertilizer. Choosing the right cover crop depends on the planting season and your local climate. From flowering clovers to winter grasses, and even food crops like okra, there are cover crops for every season and a variety of purposes. Here are 13 of the best cover crops that small-scale farmers can grow to improve soil quality. Warning Some of the plants on this list are toxic to pets. For more information about the safety of specific plants, consult the ASPCA's searchable database. 1 of 13 Winter Rye (Secale cereale) Tier Und Naturfotografie J und C Sohns / Getty Images Winter rye is a great annual late-season cover crop to plant in the fall or early winter. It can even be planted after the first light frost and still grow tall enough to be a viable cover crop. With its deep root system, it's highly drought resistant and excels at loosening compacted soil. It's often planted in tandem with a legume like clover, which gives a structure for these climbing plants to ascend and provides the next season's crop with nitrogen in the soil. USDA Growing Zones: 3-10.Sun Exposure: Full sun or partial shade.Soil Needs: Prefers well-drained, loamy soil; tolerates both dry, sandy soil and heavy clay. 2 of 13 Common Buckwheat (Fagopyrum esculentum) imagenavi / Getty Images Common buckwheat is an excellent choice for a fast-growing summer season ground cover. This annual grain can prevent erosion, outcompete weeds, and attract pollinators with its abundant blossoms. Because it can reach maturity in 70 to 90 days, it's an ideal crop in fields and garden beds that would otherwise go unused in between spring and fall cool-weather crops. It also has a large, fine root system that can access phosphorus in the soil efficiently, leaving it on hand for the next crop. It's important to cut or mow buckwheat before it goes to seed, as it can become a weed in the next planting otherwise. USDA Growing Zones: 4-11.Sun Exposure: Full sun.Soil Needs: Prefers well-drained soil; can tolerate acidic, alkaline, heavy, and light soil. 3 of 13 Crimson Clover (Trifolium incarnatum) KOKI TAKADA / Getty Images Crimson clover is a widely used annual cover crop that is useful for its role as a nitrogen fixer that adds fertility to your soil. For winter use, it should be planted six to eight weeks before the first expected frost. It can survive winters in warmer climates, but will generally die off over winter in zone five or lower. It can also be planted in spring, as soon as frost danger has passed, to prepare soil for summer crops. Thanks to its shade tolerance, it can be used in orchards to prevent erosion. USDA Growing Zones: 4-10.Sun Exposure: Full sun or partial shade.Soil Needs: Prefers well-drained sandy loam; grows in most soil types except very acidic or alkaline soils. 4 of 13 Sorghum-Sudangrass (Sorghum × drummondii) dszc / Getty Images Sorghum-sudangrass is a hybrid annual cover crop that grows quickly, prefers the heat of summer and forms an extensive root structure. Due to its fast growth rate, it's a great weed suppressor. It can be mowed down several times over the course of the summer, which prevents it from going to seed and increases the root system even further. It's an especially effective crop when it comes to revitalizing compacted and overfarmed fields. USDA Growing Zones: 4-10.Sun Exposure: Full sun or partial shade.Soil Needs: Prefers well-drained, fertile soil; tolerates most soil. 5 of 13 Hairy Vetch (Vicia cracca) Grigorii_Pisotckii / Getty Images Hairy vetch is an annual legume known for its winter hardiness that is commonly grown in northern climates. It's well-suited to use as a winter companion plant for tomatoes, which can be planted in the mulch of the cut hairy vetch in spring. It's a powerful nitrogen fixer, especially when allowed to grow over the winter and into spring. Like other legumes, it's important to mow or cut before it goes to seed. Its fragile seed pods shatter easily, which can lead to it regrowing as a weed later in the season. USDA Growing Zones: 3-10.Sun Exposure: Full sun to partial afternoon shade.Soil Needs: Prefers well-drained, slightly acidic soil with high fertility. 6 of 13 Partridge Pea (Chamaecrista fasciculata) Steven Autry / Getty Images Partridge pea is a short-lived annual plant with showy, yellow flowers. It's often used as an trap crop to attract predators (like wasps) that attack and mitigate pests (like stink bugs) that feed on other nearby crops. It also provides ground cover and food for quail and other game birds. Like clovers, it's a source of nitrogen, and is also considered a great erosion control species. USDA Growing Zones: 3-9.Sun Exposure: Prefers full sun, will survive shade.Soil Needs: Prefers sandy or slightly loamy soil; requires little water. 7 of 13 Okra (Abelmoschus esculentus) Chunumunu / Getty Images Okra might seem like a strange choice for a cover crop, but it's catching on among with farmers who are willing to experiment. This flowering plant is mostly grown as an annual vegetable crop thanks to its edible seed pods, but its fast growth and drought tolerance makes it a perfect summer cover crop, as well. It has long tap roots that help break up compacted soil and retain valuable moisture. That you can harvest it for food all summer before cutting it down to mulch your fields is just an added bonus. USDA Growing Zones: 2-11.Sun Exposure: Full sun.Soil Needs: Moist, fertile, well-drained soil, prefers neutral pH soil. 8 of 13 Mustard (Brassica napus) Peter Olsen Photography / Getty Images Mustard is a cool-season spring annual that makes a good cover crop thanks to its chemical makeup. It is high in glucosinolates, compounds with a biofumigant response that helps repel common pests that plague a number of common vegetable crops, including potatoes, onions, peas, and carrots. Mustard matures in 80 to 95 days and should be mowed or cut when it begins to flower. It's best to incorporate the cut forage into the soil immediately. USDA Growing Zones: 4-11.Sun Exposure: Full sun or partial shade.Soil Needs: Adapted to fertile, loamy, well-drained soils; tolerates variable soil types that drain well. 9 of 13 Cowpeas (Vigna unguiculata) Maria Dattola Photography / Getty Images Cowpeas, also known as black-eyed peas, are an annual legume that are used as a cover crop because of their deep taproots and role as a nitrogen source. It's a summer crop that grows well in across the eastern United States. Though you can find bushy varieties, the taller, vining types are better suited as cover crops. Cowpeas are often used as a companion crop to corn, which thrives in similar climates. USDA Growing Zones: 2-11.Sun Exposure: Full sun or partial shade; can get moldy if overshaded.Soil Needs: Slightly acidic, fertile, well-draining soil; add organic matter to poor soil if possible. 10 of 13 Common Oat (Avena sativa) Westend61 / Getty Images The common oat plant has been widely used as a cover crop for many years. This annual grass grows quickly in fall weather and can be planted directly after the main summer vegetable harvest. In zones seven and below, it will die off over winter. In warmer climates, it can survive mild winters. It works well paired with legume cover crops like clovers, because it will gather soil nutrients that boost the productivity of its companion species. USDA Growing Zones: 2-10.Sun Exposure: Full sun or partial shade.Soil Needs: Acidic, well-drained, fertile soil. 11 of 13 Alfalfa (Medicago sativa) Edwin Remsberg / Getty Images Alfalfa is known for its deep, strong tap root that can reduce soil compaction over years of use as a cover crop. It can also protect sandy soil from erosion and improve the soil structure, particularly its permeability and infiltration. The roots, both main and lateral, contain nitrogen-fixing nodules. Alfalfa grows quickly, reaching 40 or 60 inches in height before it's ready to be harvested, and is relatively shade-tolerant, though it prefers full sun. USDA Growing Zones: 2-9.Sun Exposure: Full sun.Soil Needs: Sandy loam, silt loam, and clay loam are optimal. 12 of 13 Barley (Hordeum vulgare) Nick Brundle Photography / Getty Images Barley is great for suppressing weed growth and preventing soil erosion. It likes semi-arid regions and light soils in cool, dry growing areas, and is good at reclaiming overworked or weedy fields. It's a spring cover crop that can be grown further north than any other cereal crop and produces more biomass than any other. Barley captures significant amounts of nitrogen, boosts soil structure, and inhibits pests like leafhoppers, aphids, and more. USDA Growing Zones: 3-8.Sun Exposure: Full sun.Soil Needs: Well-drained, loamy soil. 13 of 13 Fava Beans PATSTOCK / Getty Images These hardy annual nitrogen fixers grow as small, upright plants. They become brittle and are easy to work back into the soil with a tiller or garden fork, or can be cut and composted. Fava beans can be started as early as the end of January or as late as early November where winters are mild. For nitrogen fixation, the plants should grow to the point of flowering, then cut plants at surface and leave on top of soil. Work in, then wait two weeks before planting anything else. USDA Growing Zones: 2-10Sun Exposure: Full to part sun, can tolerate partial shadeSoil Needs: Loamy, moist, well-drained How to Choose a Cover Crop If you are struggling to determine which cover crop to use, take a look at this helpful breakdown by Marianne Sarrantonio, from Sustainable Agriculture Research and Education (SARE). She explains how to go about narrowing down the options, starting with clarifying your primary needs, then identifying the best time and place for a cover crop in your system, and then testing a few options. Goals may include providing nitrogen, adding organic matter, reducing soil erosion, controlling weeds, or improving soil structure. You may want better drainage or a way to attract pollinators. You have to consider your work schedule, when the field is lying fallow between harvests, and what subsequent crops you plan to plant. Consider how the weather and soil conditions will be, and how you plan to kill the cover crop and plant into it. Plan ahead for greater success. To check if a plant is considered invasive in your area, go to the National Invasive Species Information Center or speak with your regional extension office or local gardening center. View Article Sources “Sorghum-Sudangrass: A Vigorous Cover Crop.” The University of Vermont. “Cover Crop, Hairy Vetch.” University of Massachusetts Amherst Extension.