What do cover crops actually do?
Bare soil loses structure and nutrients to wind and rain. A cover crop keeps living roots in the ground and a layer of green growth over it. Roots open channels for water and air, and when the plants break down, they feed soil life and add organic matter.
Cover crops can also crowd out weeds, hold nutrients that might otherwise wash away, and in some cases add nitrogen. The results depend on the species, the timing, and how well you manage them.
Which cover crop should I choose?
Choose by purpose first. Grasses and cereals grow fast, hold soil in place, and produce a lot of biomass. Legumes can add nitrogen through partnerships with soil bacteria and are often used before a crop that needs a lot of it. Brassicas and other broadleaf covers can open compacted soil and scavenge nutrients.
Mixes combine strengths, but simple single species are easier to manage. Ask your extension office which species and varieties perform in your region, and when they should be planted.
- Grasses and cereals: erosion control and biomass
- Legumes: nitrogen contribution
- Brassicas: scavenging and loosening soil
- Mixes: several benefits, more management
When do I plant and when do I stop the cover?
Timing is the heart of cover cropping. A late summer or fall planting needs enough time to establish before cold weather, while a spring planting competes with your cash crop schedule. Fit the cover into gaps in your rotation rather than forcing it into a crowded calendar.
Terminating the cover before it sets seed prevents it from becoming a weed. Methods include mowing, rolling, tillage, or letting winter kill it, depending on the species. Your extension office can tell you which species winter kill in your area and which survive.
How do I manage the next crop after a cover?
Residue from a heavy cover can tie up nitrogen for a time as it breaks down, and it can make seedbeds hard to prepare. Allow time between terminating the cover and planting the next crop, and ask local experts how long that gap should be for the species you use.
Some growers transplant into residue and avoid direct seeding there, because small seeds can struggle in thick mulch. Learn what works on your equipment and soil with a small trial before committing the whole farm.
What equipment and seed costs should I expect?
You can start with hand tools and a small seeder on a few beds. Larger fields need a drill or broadcaster and a mower or roller. Seed prices change, so compare sources and ask whether neighbors want to share a large seed order and equipment.
Programs sometimes help with the cost of conservation practices such as cover crops. Ask your local NRCS or Farm Service Agency office whether any program fits your farm and what the application steps are.
- Start with a trial block
- Share equipment and seed orders with neighbors
- Ask NRCS about conservation assistance
- Keep notes on seeding date and results
What mistakes should I avoid?
Common mistakes include planting too late, letting a cover go to seed, planting a species that does not fit the following crop, and skipping the trial. Each is easy to avoid with a plan and a calendar.
Be patient. The benefits build over several seasons, and your own records will show you which covers earn their place.
Can cover crops cause problems?
Yes, and it is better to know that up front. A cover that sets seed becomes a weed in the next crop. A heavy residue can slow soil warming in spring, which delays planting in cold ground. Some covers share pests or diseases with the cash crops that follow them, so match species to your rotation.
Wet springs can delay termination and planting, and dry years can leave a cover competing with the following crop for moisture. None of this is a reason to avoid covers, only a reason to start small and keep notes on each species in each season.
If you graze livestock on covers, ask your extension office about species that are safe for your animals and how long to wait before and after grazing. Do not guess when animal health is involved.
- Terminate before seed set
- Expect slower spring warming under heavy residue
- Match the cover to the crop that follows
- Check with extension before grazing covers
Key takeaways
- Cover crops protect soil, suppress weeds, and add organic matter.
- Choose by purpose: grass, legume, or brassica.
- Timing of planting and termination decides success.
- Ask NRCS about program help and your extension office about species.
Sources and further reading
Last reviewed: November 12, 2026. Written by the Rural Farm Life Editorial Team. See our editorial policy.