How to Grow Non-Brassica Cover Crops

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Non-Brassica Cover Crops

Various species (see description)

grass

Non-brassica cover crops are plants grown primarily to protect and improve soil rather than for harvest. They include legumes (nitrogen-fixing), grasses, and other species that prevent erosion, suppress weeds, improve soil structure, and add organic matter when tilled in.

Looking for a specific variety?

Winter Rye Hairy Vetch Red Clover Buckwheat Oats Alfalfa

When should you plant Non-Brassica Cover Crops in your zone?

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Example Non-Brassica Cover Crops timeline · Pittsburgh, PA (Zone 6b)

Plant Non-Brassica Cover Crops
Around Apr 17

Near Pittsburgh's average last spring frost.
Tend & protect
Late spring–summer

Watering, feeding, and pest-watch reminders.
Harvest Non-Brassica Cover Crops
Around Jun 1

≈ 45 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Non-Brassica Cover Crops dates for your own zip code.

Growing Conditions

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Sun: Full sun, 6+ hours daily (most species); some tolerate partial shade

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Water: Establish with regular moisture (1-1.5 inches weekly until established). Mature cover crops are often drought-tolerant; water during extended dry spells for root development.

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Spacing: Direct sown at broadcast rates (typically 50-200 lbs/acre depending on species); thin to 2-4 inches apart if row-seeded inches

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Days to maturity: 45-150 days depending on species and intended termination timing; often grown 8-16 weeks before incorporation

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Planting depth: 0.5-1.5 inches for most seeds; legumes shallower (0.5-1 inch), grasses slightly deeper (1-1.5 inches)

Soil

Type: Highly adaptable; most non-brassica cover crops tolerate poor to moderate soil

pH: 5.5-7.5 (species-dependent; legumes prefer 6.0-7.0)

Amendments:

Inoculant for legumes to enhance nitrogen fixation Phosphorus and potassium for balanced growth Lime if pH is below 5.5

Growing Zones

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Zones vary by species; cool-season grasses and legumes thrive in 3-7, warm-season varieties in 6-10

1a 1b 2a 2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b 10a 10b

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Growth Stages

Germination & Seedling

2-3 weeks

Seeds sprout and develop first true leaves; seedlings are tender and susceptible to competition

Ensure consistent moisture; suppress aggressive weeds during this 2-3 week period. Avoid heavy foot traffic.

Establishment

3-6 weeks

Root system deepens, leaf area expands; plants develop secondary branches and become more vigorous

Maintain adequate moisture; reduce inputs once actively growing. Monitor for early pest or disease issues.

Vegetative Growth

4-10 weeks

Rapid above- and below-ground biomass accumulation; canopy closes to suppress weeds and retain soil moisture

Minimal intervention needed; legumes will nodulate and fix nitrogen. Allow adequate time for biomass production.

Flowering/Reproductive

2-4 weeks

Grasses head out, legumes flower; peak nutrient uptake and biomass. System at maximum soil benefit.

Plan termination timing to maximize benefits without allowing seed set (which may create future weeds)

Termination & Incorporation

Variable; 14-30 days before next planting

Cover crop is killed via frost, herbicide, or mechanical termination; biomass is incorporated into soil

Terminate 2-4 weeks before planting cash crop to allow decomposition. Legumes benefit from extra wait time to release nitrogen.

Companion Planting

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Plant with:

Multiple cover crop species mixed (e.g., rye + clover) Radish (in brassica-inclusive mixes) Oats Buckwheat Hairy vetch Alfalfa

Avoid planting near:

Cash crops during cover crop growing season (they compete for resources) Allelopathic plants that inhibit germination in subsequent seasons

Common Pests

Typically not problematic in cover crops; if severe, allow natural predators or mow to disrupt life cycle
and
Rarely damaging to established cover crops; copper barriers or encouraging natural predators if needed
Marigold or certain cover crop species (e.g., rye) suppress nematodes; avoid susceptible species in infested fields
Uncommon; encourage natural enemies; mite-resistant varieties available

Uses

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Soil improvement & erosion control

Household

Cover crops prevent topsoil loss, improve soil structure, increase water infiltration, and add organic matter that enhances microbial activity. This is the primary agronomic benefit. [source]

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Nitrogen fixation (legume cover crops)

Culinary

Legumes like clover, vetch, and alfalfa form symbiotic relationships with rhizobia bacteria to convert atmospheric nitrogen into plant-available forms, reducing synthetic fertilizer needs for subsequent crops. [source]

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Forage & habitat for pollinators and beneficial insects

Wildlife

Flowering cover crops (clover, vetch, buckwheat) provide nectar and pollen for bees, butterflies, and other beneficial insects, supporting ecosystem health and natural pest control. [source]

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Weed suppression

Household

Dense cover crop canopy outcompetes weeds for light, water, and nutrients, reducing weed pressure before cash crop planting and minimizing herbicide use. [source]

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Phytoremediation potential

Medicinal

Some cover crops (e.g., sunflower) can accumulate excess nutrients or help remediate contaminated soils, making them useful in regenerative and sustainable agriculture systems. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Non-brassica cover crops are typically not harvested for marketable yield. Instead, terminate at peak biomass and nutrient content (late flowering/early seed stage, 8-16 weeks after planting). Kill via frost (winter-kill varieties), herbicide spray, mechanical mowing, or tillage. Incorporate 2-4 weeks before planting cash crops to allow decomposition and nitrogen release.

Fun Facts

🌱 Winter rye is one of the most winter-hardy cover crops and can germinate even in cold soil, making it ideal for fall planting in temperate climates; it also produces allelopathic compounds that naturally suppress weeds.
🌱 A single acre of legume cover crop can fix 100-300 pounds of atmospheric nitrogen, equivalent to $20-60 worth of synthetic fertilizer, making it an economical soil-building strategy.
🌱 Cover crops have been used for thousands of years; the Romans called them 'green manure' and rotated fields between crops and legumes to maintain fertility without chemical inputs.

Gardening Terms

New to gardening? Learn about terms used in this guide:

Cover Crop Full Sun Partial Shade True Leaves

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