Cover crops are plants grown primarily to benefit the soil rather than for harvest. They're planted when beds would otherwise be bare, typically in fall after summer crops finish or in beds resting between crop rotations.

Benefits include: - Nitrogen fixation: Legume cover crops (clover, peas, vetch) capture nitrogen from the air and store it in root nodules, then release it when incorporated into soil. - Erosion prevention: Roots hold soil in place; foliage protects from rain impact. - Weed suppression: Dense growth outcompetes weeds. - Organic matter: When turned under, cover crops add biomass that feeds soil life. - Soil structure: Roots break up compaction and create channels for water and air.

For market gardeners, cover crops are a natural, low-cost way to maintain soil fertility without purchased inputs.

Legumes (fix nitrogen): - Crimson Clover: Beautiful red flowers, fixes lots of nitrogen. Plant fall for spring incorporation. - Winter Peas: Cold-hardy, large biomass. Great for heavy clay. - Hairy Vetch: Very cold-hardy, excellent nitrogen fixer. Can be hard to terminate.

Grasses (add organic matter, scavenge nutrients): - Winter Rye: Extremely cold-hardy, easy to grow. Extensive roots break compaction. - Oats: Quick to establish, winter-kills in cold climates for easy incorporation. - Annual Ryegrass: Fast germination, good for short windows.

Brassicas (break compaction, scavenge nutrients): - Tillage Radish: Deep taproot breaks hardpan. Winter-kills. - Mustard: Fast-growing, may suppress soil-borne diseases.

Combinations often work best. A classic mix is winter rye + crimson clover: the rye provides quick cover while the clover establishes.

Fall Cover Crops (most common): - Plant 4-6 weeks before first fall frost - In Zone 7, that's typically late September to early October - Seeds need time to establish before cold weather - Will grow through fall, overwinter, resume growth in spring

Spring Cover Crops: - Plant as soon as soil can be worked - Good for beds that won't be planted until summer - Choose fast-growing options like oats or buckwheat

Summer Cover Crops: - Buckwheat is the classic choice - 30 days to flower - Fills short gaps between spring and fall plantings - Excellent for attracting pollinators

Check your LocalRoots Growing Profile for frost dates to time fall plantings correctly.

Cover crops are generally broadcast sown (scattered) rather than planted in rows:

1. Clear the bed of crop residue and weeds.

1. Rake smooth and remove large debris.

1. Calculate seed rate: Package will specify per 1000 sq ft. For a 100 sq ft bed, use 1/10 of that amount.

1. Broadcast seed by hand, walking across the bed in two perpendicular passes for even coverage.

1. Rake lightly to cover seeds 1/4 to 1/2 inch deep.

1. Water gently and keep moist until germination.

Alternative - understory planting: Broadcast cover crop seeds between rows of summer crops 4-6 weeks before expected frost. The cover crop establishes under the main crop and takes over after harvest.

Cover crops must be killed and incorporated before planting your next cash crop. Timing is critical - kill them too late and they'll compete with your vegetables.

When to terminate: 2-3 weeks before you want to plant. This allows decomposition time.

Methods

1. Mow/cut then till: Cut cover crop at ground level, let wilt 2-3 days, then turn under with a fork or tiller.

1. Smother method: Mow low, cover with cardboard or tarps for 3-4 weeks. No tillage required.

1. Winter-kill: Some covers (oats, tillage radish) die in cold winters. Just rake aside dead material in spring.

1. Crimp-roll: For no-till gardeners - flatten the crop, then transplant directly into the mulch.

Important: Kill legume covers at peak flowering for maximum nitrogen release. Grasses should be terminated before seed heads form.

For a typical Zone 6-7 garden

August-September: Plant fall brassicas cover (tillage radish) after early summer crops finish.

September-October: Plant winter rye/clover mix after tomatoes and peppers finish.

April: Terminate overwintered cover crop. Wait 2-3 weeks before planting.

May-June: Plant buckwheat in beds waiting for warm-season transplants.

July: Mow buckwheat at flowering. Can replant for second round.

Adjust dates based on your specific frost dates. The goal is never having bare soil - it's either growing food or growing soil fertility.