Cover Crops for Summer: Selection, Planting & Care

Summer cover crops turn an open bed or field into a working part of the rotation. Warm-season species can cover bare soil, compete with weeds, produce organic matter, capture nutrients, support beneficial insects, and—in the case of properly nodulated legumes—fix nitrogen. The best choice depends on how many frost-free days you have, how much water is available, what you want the crop to accomplish, and how you will terminate it before the next planting.

Choosing for a home garden? Use the Cover Crop Selector for Home Gardens to answer a few quick questions and get recommendations based on your growing space, season, and garden goals—plus estimated seed and inoculant needs.

Use this guide when choosing a cover crop for late spring, summer, or an early-fall gap. For year-round fundamentals, see How to Grow Cover Crops. To compare seed now, browse Warm Weather Cover Crops.

Quick summer cover crop decision

Primary need	Planning direction
Very short warm-weather gap	Start with a quick-establishing option and confirm that useful growth fits before the next crop.
Nitrogen fixation	Choose a heat-adapted legume and verify compatible rhizobia, moisture, and enough growing time.
High biomass or vigorous roots	Choose a warm-season grass only when water, equipment, and termination time can handle the growth.
Several complementary goals	Compare a purpose-built mixture with a single species rather than assuming more species are automatically better.

Compare individual choices in 7 Summer Cover Crops: Uses & Tradeoffs. Measure the planting area with the Cover Crop Seed Rate Calculator, then replace its default range with the selected product’s current rate when one is listed.

When does a summer cover crop make sense?

A summer cover crop is useful when soil would otherwise remain bare for several weeks or months. Common opportunities include an empty garden bed between spring and fall vegetables, a resting production block, a new growing area being prepared for later planting, or a field where rapid biomass or weed competition is needed.

Count backward from the next crop's planting date. Include time for establishment, useful growth, termination, and residue management. A crop that needs a long, hot season is a poor fit for a short gap, even if it grows well in your climate. Conversely, a quick crop may be terminated before a long-season grass or legume reaches its potential.

Choose summer cover crops by goal and growing window

Short windows and rapid soil cover

Buckwheat is widely used for quick warm-season cover. It germinates rapidly under suitable conditions, creates a canopy that can compete with weeds, and flowers relatively early. It is sensitive to frost and can set seed if left too long, so monitor it closely and plan termination before mature seed becomes a problem.

Buckwheat is not a grass and does not fix nitrogen. Its value is rapid cover, fine roots, pollinator forage when flowering is allowed, and residue that is generally easier to manage than a mature high-biomass grass. Shop warm-weather options and check each product page for its recommended planting window.

Nitrogen fixation in hot weather

Cowpeas and sunn hemp are warm-season legumes used where heat and a sufficient growing window are available. Successful nitrogen fixation requires compatible Rhizobium bacteria and adequate plant growth. Nitrogen contribution varies with species, biomass, nodulation, soil conditions, and termination timing; it should not be treated as a guaranteed replacement for a fixed amount of fertilizer.

Confirm whether the seed is raw, coated, or Nitrocoated on the current product listing. A coating does not automatically mean that the correct live inoculant is included. When a compatible current inoculant is not clearly included—especially with raw seed or where that legume has not been grown recently—apply the correct inoculant according to its label. Compare legume cover crops and inoculants, and read Nitrogen-Fixing Cover Crops.

Biomass, roots, and weed competition

Sorghum-sudangrass, sudangrass, and warm-season millets can produce substantial roots and above-ground biomass when planted into warm soil with adequate time and moisture. These grasses can be useful for covering large areas, capturing residual nutrients, and competing with weeds after establishment.

High-biomass grasses require a realistic termination plan. Mature stems and heavy residue may be difficult to incorporate with small garden equipment and can delay the following crop. Select a manageable acreage, monitor height, and mow or terminate at a stage appropriate to the species and your equipment.

Multiple goals in one planting

A mixture can combine a legume for nitrogen fixation with a grass or broadleaf crop for biomass, nutrient capture, or faster soil coverage. Mixtures can be resilient, but their components may have different seed sizes, planting depths, maturity dates, and termination responses. Use the mixture's own seeding and management instructions rather than averaging recommendations from its ingredients. Browse Cover Crop Mixes.

Summer cover crop comparison

• Buckwheat: best suited to relatively short warm-season gaps and quick canopy development; frost-sensitive and should be monitored for seed formation.
• Cowpeas: heat-loving legume for nitrogen fixation and cover; requires the correct compatible rhizobia for dependable nodulation.
• Sunn hemp: warm-season legume capable of rapid biomass under suitable heat and day length; allow enough growing time and plan termination.
• Sorghum-sudangrass or sudangrass: strong biomass and root production; needs warm conditions, moisture, and equipment capable of managing vigorous growth.
• Japanese or other warm-season millets: grasses used for quick growth, soil coverage, and biomass; suitability varies by species and local conditions.
• Summer mixtures: combine traits but require attention to inoculation, seed distribution, maturity, and termination of every component.

The Cover Crop Solution Chart provides a broader comparison. Individual product pages remain the source for current seed treatment, seeding rate, planting depth, and acreage coverage.

Plan around heat and water

Warm-season does not mean no-water. Even drought-tolerant plants need moisture to germinate and establish. Decide how the seed zone will be kept moist before planting. In an irrigated garden, light, even watering may be needed until roots develop. In rain-fed production, plant when dependable moisture is expected rather than broadcasting seed onto dry ground.

Cover crops also use water while growing. That can be helpful where excess moisture is an issue, but it may reduce stored soil moisture before the following crop. In dry climates, terminate early enough to protect the next planting's water supply and consider leaving residue on the surface where appropriate.

Prepare and plant

1. Define the goal and deadline. Choose rapid cover, nitrogen, biomass, weed competition, or a combination, then set the latest acceptable termination date.
2. Control established weeds. Summer weeds can grow as quickly as the cover crop. Do not expect new seedlings to overcome mature weeds.
3. Prepare for seed-to-soil contact. A firm, even seedbed helps produce uniform depth and moisture. Avoid pulverizing soil into a surface that will crust.
4. Measure the area and seed. Follow the rate on the product page. Different species and mixtures cannot share one universal rate.
5. Inoculate legumes when needed. Match the inoculant to the crop, protect it from heat and direct sunlight, and plant promptly.
6. Drill or broadcast correctly. A drill can control depth on larger areas. In gardens, broadcast in two perpendicular passes, rake or incorporate only to the recommended depth, and firm the surface.
7. Water for establishment. Keep the seed zone adequately moist without washing seed away or creating standing water.

Manage the growing stand

Inspect emergence and identify thin areas early. Poor establishment can result from planting too deep, inadequate moisture, soil crusting, high soil-surface temperatures, uneven broadcasting, birds, or seed planted outside its preferred conditions. Correct the underlying problem before reseeding.

Monitor weeds, lodging, flowering, seed development, and water use. Mowing some vigorous grasses can encourage additional root and shoot growth when performed at an appropriate stage, but repeated mowing is not suitable for every species. Follow product-specific guidance and never assume that one management schedule applies to all summer covers.

Terminate before the next crop

Select the termination method before you seed. Options include mowing, cutting, rolling, shallow incorporation, grazing where appropriate, tarping, or a combination. Summer species may be killed by frost, but relying on eventual winterkill does not solve scheduling problems when a fall crop must be planted first.

Earlier termination generally means less biomass and more tender residue. Later termination may provide more growth but can increase water use, fibrous residue, regrowth, and viable seed. Leave enough time for residue to wilt or decompose based on the species, soil moisture, temperature, and planting method for the next crop.

For detailed planning, read When to Cut Down Your Cover Crop and Turning Cover Crops into Green Manure. When shopping green-manure options, use Green Manure Seeds.

Common summer cover crop mistakes

• Choosing a long-season crop for a gap that is too short.
• Planting into dry soil without a realistic irrigation or rainfall plan.
• Assuming every legume seed coating includes the correct inoculant.
• Letting buckwheat or another crop produce viable seed when volunteer plants are unwanted.
• Growing more grass biomass than the available mower or tiller can manage.
• Ignoring the water and time needed by the following vegetable or cash crop.
• Using a general seeding rate instead of the current product instructions.

Build your summer cover crop plan

Start with the length of your open window, then choose the most important result. Use buckwheat or another suitable quick crop for short gaps; consider warm-season legumes where nitrogen fixation and compatible inoculation are priorities; choose warm-season grasses where biomass and root production are worth the added management; or select a mixture when several complementary benefits fit your schedule.

Shop Warm Weather Cover Crops, compare Organic Cover Crop Seeds, or browse All Cover Crop Seeds. Products that remain available for sale while temporarily out of stock may still be useful for planning a future planting.

Planting a legume? If the seed is raw rather than pre-inoculated or Nitrocoated, use the Legume Inoculant Compatibility Chart to match clover, vetch, peas, beans, and other legumes with a compatible rhizobia group before planting.