Planting cover crops is a powerful way to improve your soil. Cover crops perform a host of valuable functions like increasing soil organic matter, fixing nitrogen, breaking up compaction, suppressing weeds and preventing erosion. In this guide we'll discuss your options for spring cover crops and the benefits of each, when and how to plant, and how to manage the crop once it's established. While commercial growers typically use a seed drill or mechanical broadcaster to plant cover crops (followed by mowing and tilling before the crop sets seed), home gardeners can grow cover crops too. For gardeners we recommend planting most cover crops by hand-broadcasting seed over freshly turned soil, then raking in lightly just before a rain. When the cover crop is in flower, just before it sets seed, it should be cut with a scythe or mower, then left as a living mulch for the rest of the season or turned under with a rototiller. Because of the nutrients bound up by the decomposing crop, it is recommended to wait 2-3 weeks after tilling before planting another crop into the area. At this point the cover crop residues will have mostly decomposed, making organic matter and nutrients available to the next crop. BMR Sorghum-Sudangrass F1 Life cycle: Annual Benefits: fast growing, tolerates drought, builds biomass, smothers and discourages weeds, penetrates compact soil. Can grow to 12’ tall with 4,000-5,000 lbs of dry matter produced per acre, easier to grow than corn (for silage) Uses: soil building, silage or green forage when 24-30” tall (not suitable for horses) When to sow: Late May to early July depending on location, or when soil reaches 60ºF Days to maturity: 90-100 Seeding rate and depth: 35 lbs/acre drilled or 40-50 lbs/acre broadcast, .5” deep in heavy soil, 1.5” deep in sandy soil How to harvest: Mow when crop reaches 36-40” tall for silage Limitations: soil temperature must reach 65ºF at least two months before first fall frost. Performs poorly in waterlogged soils Learn more about Sorghum-Sudangrass for silage here   Common Buckwheat Life cycle: Annual Benefits: a rapid grower widely used for smothering weeds, lightening heavy soils, holding nutrients for the next crop and attracting pollinators Uses: as a green manure in rotation with vegetable crops, for grain When to sow: late May through July or when soil is at least 50ºF, at least 3 months before first frost for grain Days to maturity: 35-42 bloom, 70-84 grain Seeding rate and depth: 2-3 lbs/1000 sq ft or 35-135 lbs/acre How to harvest: for green manure mow or harrow before seeds mature, about one month after planting. For grain cut when 80-90% of seeds have turned brown, after killing frost Limitations: does not tolerate waterlogged soils or very hot, dry weather (later planting is recommended for Southern growers to avoid the hottest part of the summer) Learn more about Buckwheat for grain production here   Medium Red Clover Life cycle: Perennial Benefits: fixes nitrogen, mines nutrients & conditions soil, tolerates shade, reduces compaction, attracts beneficial insects, tolerates poor/wet/acid soils, produces 2-4 tons dry matter/acre in 2nd year Uses: soil builder, ground cover, undersown in existing crops, insectary, hay and forage When to sow: Spring to summer when soil is above 41ºF Days to maturity: 14 months when spring sown Seeding rate and depth: Broadcast, drilled or frostseeded 1/2 lb/1,000 sq ft or 5-15 lbs/acre, ¼-1/2” deep How to harvest: Incorporate once blooming begins in spring of 2nd year by mowing and/or tilling under Limitations: not exceptionally heat-tolerant; growers in the South should plant in late summer/fall for overwintering TIP: “Frostseeding” can be effective at least a month before last frost; sow in early morning when soil is still frost-covered   Field Peas Life cycle: Annual Benefits: fixes nitrogen, builds soil, moderate weed suppression, biomass decomposes quickly, edible tops Uses: soil builder, edible tendrils, forage crop When to sow: Early spring as soon as soil can be worked Days to maturity: 52-75 Seeding rate and depth: 5 lbs/1,000 sq ft or 200 lbs/acre, 1 ½ to 3” deep How to harvest: Till when flowering begins Limitations: does not tolerate hot, dry conditions; growers in the South should use as fall/winter crop in areas where legumes have not been grown recently TIP: Oats support weak pea stems and act as a “nurse” crop; sow 120 lbs of peas with 2 bushels of oats per acre   Improved White Clover Life cycle: Perennial Benefits: fixes nitrogen, reduces compaction, improves soil health, tolerates mowing/trampling/wet soils/drought Uses: soil builder, excellent for paths and lawns, undersow around existing crops for living mulch, green manure, hay, pasture forage When to sow: Anytime, preferably before a rain Days to maturity: 60-70 Seeding rate and depth: ¼ lb/1,000 sq ft, 5-9 lbs/acre drilled, 7-14 lbs/acre broadcast then rolled, raked or cultivated to ensure good soil contact How to harvest: Chisel or moldboard plow to kill; regular mowing to maintain Limitations: Slow to establish, not ideal for smothering weeds. TIP: Combine with Annual Ryegrass to increase soil benefits. “Frostseeding” can be effective a month before last frost; sow in early morning when soil is still frost-covered   Oats Life cycle: Annual Benefits: fast grower, prevents erosion, suppresses weeds, scavenges nutrients, builds biomass with up to 8,000 lbs/acre dry matter from spring stands Uses: soil builder, nurse crop for legumes, green manure, grain, hay When to sow: Early spring to summer, when soil is at least 38ºF Days to maturity: 100-120 for grain Seeding rate and depth: Broadcast or drill 4 lbs/1,000 sq ft or 100-140 lbs/acre 1” deep How to harvest: Till in when seedheads are just forming, or cut grain when seeds harden Limitations: performs poorly in hot, dry weather; Southern growers should plant in fall   Annual Ryegrass Life cycle: Annual Benefits: fast grower, suppresses weeds, controls erosion, adds organic matter, catches nutrients, thrives in all soil types Uses: soil builder, nurse crop, emergency forage When to sow: Anytime soil is at least 40ºF Days to maturity: 50-70 Seeding rate and depth: Broadcast 20-30 lbs/acre or drill 10-20 lbs/acre ½” deep How to harvest: Disk, till or plow under as soon as flowers form Limitations: occasionally some plants overwinter and become weedy   Yellow Sweet Clover Life cycle: Biennial Benefits: nitrogen-fixer, mines nutrients from deep in soil, drought-tolerant, attracts beneficials, tolerates poor soil, adds up to 2.5 tons dry matter/acre in first year Uses: excellent green manure, soil builder, subsoil aerator, and honey plant When to sow: Spring to summer when soil is at least 42ºF Days to maturity: 60-70 to bloom Seeding rate and depth: Broadcast ½ lb/1,000 sq ft or 15-20 lbs/acre, drill 8-15 lbs/acre How to harvest: Kill early in 2nd year by mowing or tilling when stalks are 6-10” tall Limitations: does not tolerate waterlogged soil; recommended for fall in the South TIP: Best grown with 2 bushels of oats as a nurse crop   Field Peas/Oats Mix Life cycle: Annual Benefits: versatile, fixes nitrogen, builds soil, suppresses weeds, decomposes quickly, edible pea tendrils Uses: versatile soil builder, marketable pea tendrils, forage crop When to sow: Early spring when soil is at least 38ºF Days to maturity: varies Seeding rate and depth: Broadcast 5 lbs/1,000 sq ft or 200 lbs/acre and rake or cultivate How to harvest: till under or otherwise incorporate before seeds are set Limitations: peas do not tolerate very hot dry weather; may be grown as a fall crop in the South   Field Peas/Oats/Vetch Mix Life cycle: Annual Benefits: versatile, fixes nitrogen, suppresses weeds, decomposes quickly, edible pea tendrils, adds up to 8,000 lbs/acre of organic matter Uses: versatile green manure, soil builder, marketable pea tendrils, forage crop When to sow: Early spring when soil is at least 38ºF Days to maturity: varies Seeding rate and depth: Broadcast 6-8 lbs/1,000 sq ft or 210 lbs/acre and rake in How to harvest: till under or otherwise incorporate before seeds are set Limitations: peas do not tolerate very hot dry weather; may be grown as a fall crop in the South