Cover Crop Planting (Green Manure): A Complete Guide for Healthy Soil

Cover crops, often called green manure, are an essential part of sustainable gardening and farming. Whether you’re managing a backyard vegetable bed or a full-scale homestead, cover cropping can transform your soil health, reduce pest pressure, and naturally increase fertility—without synthetic inputs.

In this comprehensive guide from PlantingWell.com, you’ll learn how to choose, grow, and manage cover crops for every season and garden type.

What Is a Cover Crop?

A cover crop is a plant grown not to harvest but to benefit the soil and surrounding ecosystem. Unlike vegetables or cash crops, cover crops are typically planted during the off-season or between planting cycles. When tilled into the soil or left as mulch, these plants act as green manure—adding organic matter, nutrients, and beneficial microbes back into the earth.

While modern gardeners are rediscovering this ancient practice, civilizations have used green manure for centuries to build fertile, productive land without synthetic fertilizers.

Benefits

Cover cropping offers a range of benefits that contribute to a thriving, resilient garden:

🌱 1. Enriches Soil Fertility

Leguminous cover crops like clover and vetch fix nitrogen from the air, making it available to future crops. Others add organic matter that improves soil texture and microbial life.

🌿 2. Suppresses Weeds Naturally

Fast-growing varieties like buckwheat and mustard quickly cover the soil, shading out unwanted weeds and reducing competition for nutrients.

💧 3. Reduces Soil Erosion

In fall and winter, cover crops protect exposed beds from wind and water erosion, especially helpful on sloped or raised beds.

🐞 4. Attracts Beneficial Insects

Many cover crops produce nectar and flowers that invite pollinators and predatory insects, enhancing natural pest control.

🧪 5. Breaks Pest & Disease Cycles

When rotated properly, cover crops help interrupt the life cycles of soil-borne pests and diseases.

Best Times to Plant Cover Crops

Timing is everything when it comes to cover cropping. You can fit them into three key seasonal windows:

Spring: Sow early-season covers before planting warm-weather crops.
Summer: Use cover crops in fallow beds or between harvests.
Fall: Plant overwintering varieties after your last harvest to prepare beds for spring.

👉 Pro Tip: Use a seasonal planting chart to schedule your cover crops alongside your main crops. You can download one for free on PlantingWell.com.

Types of Cover Crops (By Function)

Different cover crops serve different purposes. Let’s break them down into four functional categories:

a. Nitrogen Fixers

These legumes form symbiotic relationships with rhizobia bacteria to convert atmospheric nitrogen into a usable form for plants.

Examples: Crimson clover, hairy vetch, field peas
Best For: Heavy feeders like corn, tomatoes, brassicas

b. Biomass Builders

Add organic matter and improve soil texture when incorporated.

Examples: Cereal rye, oats, buckwheat
Best For: Increasing soil carbon and improving tilth

c. Weed Suppressors

Fast germinating and dense growth cover the soil and choke out weed seeds.

Examples: Barley, buckwheat, mustard
Best For: Beds with persistent weed problems

d. Soil Breakers / Compaction Reducers

These deep-rooted plants break up compacted layers and aerate the soil naturally.

Examples: Daikon radish, annual ryegrass, turnips
Best For: Clay-heavy or no-till beds

How to Plant Cover Crops

Planting cover crops is simple—but requires a few essential steps to be effective.

1. Prepare the Bed

Remove spent plants and debris. Lightly till or loosen the top layer of soil.

2. Broadcast or Drill Seeds

Broadcasting: Spread seeds evenly by hand and lightly rake in.
Drilling: Use a seed drill or trench to space seeds for larger areas.

3. Water and Monitor

Water the area thoroughly after sowing, especially in dry periods. Germination usually occurs within 5–10 days.

How to Manage and Terminate Cover Crops

Knowing when and how to terminate cover crops is crucial.

🌼 When to Cut

Before flowering for maximum nitrogen retention
After flowering for biomass and pollinator benefits

✂️ How to Terminate

Mow or cut close to the soil surface
Tilling: Incorporate the residue 2–3 weeks before planting
No-till: Leave the cut cover as mulch (great for weed suppression)

Replenishing Soil Between Successions

Each crop depletes nutrients. To keep soil fertile:

🐛 Add compost between plantings
🌾 Rotate crop families (e.g., legumes after leafy greens)
🧪 Use soil tests to determine amendments needed

For organic solutions, refer to our guide on How to Make Organic Fertilizer at Home. Avoid synthetic fertilizers that can damage long-term soil health.

Best Cover Crops by Season & Climate

❄️ Cool Season

Winter Rye – Hardy and great biomass
Hairy Vetch – Nitrogen fixer, overwintering
Crimson Clover – Mild winters, pollinator-friendly

☀️ Warm Season

Buckwheat – Fast growth, suppresses weeds
Sorghum-Sudangrass – High biomass, suppresses nematodes
Cowpeas – Nitrogen fixer, thrives in heat

🌎 Regional Tips

Zones 4–6: Use winter-hardy species like rye or vetch
Zones 7–9: Try cowpeas, millet, and crimson clover for mild winters

Cover Crops for Raised Beds and Small Gardens

You don’t need acres to benefit from cover cropping. For urban gardens and raised beds, choose:

Buckwheat for quick turnover
Crimson Clover for nitrogen
Oats for light biomass and weed control

Try interplanting with vegetables like tomatoes or using micro cover crops between crop rows.

Common Succession Planting Mistakes

❌ Planting too closely: Causes overcrowding and competition
❌ Ignoring maturity dates: Leads to wasted seed or harvest gaps
❌ Skipping soil amendments: Results in poor growth or nutrient deficiencies
❌ Not tracking timing: Forgetting what was planted where slows your progress

Grow Green, Build Soil, and Reap Rewards

Incorporating cover crops (green manure) into your garden planning is a game-changer. Whether you’re improving depleted soil, preparing for a new growing season, or simply building long-term fertility—cover cropping is one of the most natural, effective strategies available.

Ready to get started? Download our free seasonal cover crop planting chart and explore more sustainable methods at PlantingWell.com.