Cover Crops: 5 Steps for Deciding What to Plant When & Where

Late summer into fall is prime time to sow winter cover crops that shield and build soil for next season. It's also a natural point to sketch out a year-round cover crop plan that makes your whole operation more sustainable over the long run.

First-time cover croppers and old hands tend to ask the same questions:

Help is everywhere, from experienced growers in your area to a wealth of online guides, charts and calculators. To make choosing cover crops for your farm more manageable, this guide follows a framework from Jason Lilley, a Cooperative Extension sustainable agriculture specialist, that splits the process into five simple steps.

Performance and roles chart from Managing Cover Crops Profitably

Start by deciding what you want the cover crop to do. Three useful places to begin:

• Northeast Cover Crop Handbook is a go-to reference for cover cropping in the Northeast.
• Managing Cover Crops Profitably, published by Sustainable Agriculture Research & Education (SARE), is another strong reference, free to download as a PDF or available in print.
• For a short summary of the main uses and benefits, read our ten main uses for cover crops and farm seed.

Most cover crops do several jobs at once, so use the charts and tools in these resources to rank your priorities.

Example four- and five-year rotations appear in the "Real Fields on Real Farms" section of the organic crop rotation planning manual

When could you plant, and how long will the cover crop stay in the ground?

Think about:

• Which crops come before the cover crop, and which will follow it?
• How will leftover residue from the cover or the previous crop affect tillage?
• What will the weather be like at that point in the season?

Use the organic crop rotation planning manual to build your rotation plan, fitting cover crops into a longer-term strategy.

The seeding and termination equipment you have shapes which cover crops make sense, and in turn, the right equipment depends on the cropping system you choose.

Core equipment includes:

Left: Broadcast seeder.   Center: Cultivating baskets and Lely tines.   Right: Cultipacker.

Broadcast seeder. A broadcast seeder can be the simplest place to start, here spreading oats into wide paths between tomato rows.

Cultivating baskets and Lely tines. Here used to work broadcast oats into the soil.

Cultipacker. Here firming soil over broadcast clover and oats. A cultipacker is a key tool for getting small-seeded cover crops established, and it's especially useful where soil moisture is hard to hold, such as in dry seasons.

Photos courtesy of a former research farm manager

Left: Roller-crimper.   Center: Yeoman's Plow.   Right: Starting with a clean field with strips cut in to receive a new cash crop.

A 10'-wide roller-crimper with chevron blades. Here ending fall-sown cover crops in spring for no-till or strip-till systems.

Yeoman's plow. Cuts 1'-wide planting strips through residue in strip-till systems. A disk slices through residue, a shank follows to lift the soil, and a basket behind it breaks up clods. Planting is usually a separate pass. It can prepare soil to roughly 8" deep.

A field ready to plant. Hairy vetch ended with a roller-crimper, in the foreground; rye rolled behind that; and mowed vetch. The rolled vetch took just over a week to die completely.

Photos courtesy of Jason Lilley

Your location affects every goal and challenge above, so factor it in when choosing which species or mixes will work best.

Plenty of region-specific help exists. These resources offer broadly useful guidance:

SARE's Cover Cropping Survey

With USDA–NIFA support, the Sustainable Agriculture Research & Education program publishes practical resources for planning and using cover crops.

• From the Midwest Cover Crop Council, the Vegetable & Row Crops Cover-Crop Decision Tool lets you compare species across several criteria.
• SARE's handbook, Managing Cover Crops Profitably is useful here too, with plenty of detail to help you match cover crops to your region and farm.
• Ask neighboring growers what works for them; they can often share specific varieties, local microclimates, and the weeds and pests to expect.
• For anyone using or curious about cover crops, the Cover Crop Survey Analysisfrom SARE and USDA–NIFA gives both the big picture and detailed findings on how U.S. growers use cover crops.

With all of this in hand, your species picked and slotted into the multiyear rotation from Step 2, it's time to carry out the plan.

• Keep records of seeding rates, where you bought seed, weather, field conditions and anything else you notice.
• Try the cover crop calculator from Oregon State University to estimate cover crop biomass and nitrogen contributions.
• Then enjoy the payoff over the seasons ahead!