Green manure crops are plants grown to cover and improve garden soil—not just to harvest. The three main groups are legumes, grasses and cereals, and brassicas. They do different jobs: legumes can add nitrogen to the garden system, grasses and cereals build soil cover and biomass, and brassicas can scavenge nutrients while producing leafy growth and deep taproots. The right choice depends on your local climate, planting window, next vegetable crop, and how you plan to end the crop.
What green manure crops do
A green manure is a cover crop grown for soil benefits such as cover, nutrient cycling, weed suppression, or added nitrogen. You can leave the crop on the surface as living or dead mulch, or incorporate plant material into the soil. The best approach depends on the species and your garden schedule.
1. Legumes: for nitrogen fixation
Clovers, field peas, and vetch are legumes often used as green manures. Their roots form nodules with bacteria that can fix atmospheric nitrogen. That does not mean a following vegetable crop receives an immediate dose: the nitrogen benefit becomes available as the terminated plant material decomposes. [UNH Extension]
Hairy vetch and some clovers can be useful choices, but their planting window and termination deserve attention. Choose them when you can establish the crop at the right time and allow sufficient time to manage it before planting vegetables. Local extension guidance can help match the species and timing to your region.
Do these 3 things before closing this tab:
1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problems#1 Best Overall
![No-Till Cover Crop 13-Seed Mix (1 lb. Bag): [50% Clovers Plus Fenugreek, Vetch, Flax, Cowpeas, Buckwheat, Forage Peas, Millet, Lentils, Crimson Clover, Sweet Yellow, White Clover, Medium Red Clover]](https://m.media-amazon.com/images/I/61tz3UL4ZfL._SL160_.jpg)
- 13 different varieties of THE most popular cover crops in the community in 1 bag = balanced bio-diversity
- Inoculated with Rhizobium; Encourages Beneficial Mycorrhizal Fungi populations to thrive, which literally help deliver nutrients to the roots of the plants
- Bio-diverse array of cover crop varieties attracts wide variety of beneficial organisms & predators which contribute to soil fertility and humus quality
- Perfect for Raised Beds and/or No-Till Container Gardening
- High-Quality, Nitro-Coated, All-Natural Non-GMO Seed Mix, From USA only
2. Grasses and cereals: for cover and biomass
Cereal rye, oats, and wheat provide soil cover and can scavenge nutrients such as residual nitrogen. Their growth habits and winter survival differ, so choose based on your climate and the time available before the next crop.
For example, New Hampshire guidance describes rye as winter-hardy, while oats may winter-kill there. Rye that grows late into spring can be difficult to terminate. These are regional observations, not universal predictions; consult advice for your area before setting planting or termination dates. [UNH Extension]
Rank #2
- 1 JUG (5 LBS.) = 3,000–3,750 SQ FT - Comes in a handy resealable container
- IMPROVES SOIL HEALTH & FERTILITY: Helps fix nitrogen, add organic matter, and improve soil structure for better growing conditions season after season
- FAST GROWING COVER FOR SPRING & FALL: Establishes quickly to protect bare soil, suppress weeds, and improve soil between planting seasons
- NATURAL NITROGEN FIXATION: Winter peas and hairy vetch work together to naturally add nitrogen back into the soil, reducing fertilizer needs
- WEED SUPPRESSION & SOIL PROTECTION: Dense growth shades out weeds and helps reduce erosion while keeping your soil covered
3. Brassicas: for nutrient scavenging and taproots
Radishes and turnips are brassica cover crops. Their leafy growth can cover soil, and their taproots may help address compacted layers. Brassicas can also take up residual nutrients, keeping them in plant growth rather than leaving them unused in the bed.
Use rotation caution if you grow cabbage-family vegetables. Brassica cover crops may carry pests relevant to related crops, so avoid placing them where they could undermine your rotation plan. Species choice and timing should follow local recommendations. [UNH Extension]
Rank #3
- Cover Crop - Nine large individual packets of Annual Buckwheat, Crimson Clover, Dutch White Clover, Hairy Vetch, Yellow Mustard, Winter Oats, Austrian Winter Pea, Daikon Driller Radish and Winter Rye seeds with instructions to grow. Seed varieties that are great for improving soil, preventing erosion, and suppressing weeds.
- Soil Health - Winter-hardy and drought-tolerant cover crops that work well on sandy or clay soils.
- For the Home Gardener - We've included enough seed in one packet to cover an 8' x 4' garden bed. Improving soil health through cover crop planting is an easy and low cost way of maintaining your garden from year to year.
- Easy to Grow - Instructions included on each packet. Plus, we are available to answer all your questions. If these seeds don’t germinate, we will happily make it right for you.
- Safe and Sustainable - Our operation is fully solar powered, and Sow Right Seeds has taken the Safe Seed Pledge to sell only fresh Non-GMO heirloom seeds for you and your family.
Compare the three groups by garden job
| Group | Main contribution | Season and timing considerations | Termination considerations |
|---|---|---|---|
| Legumes: clovers, field peas, vetch | Fix atmospheric nitrogen through root-nodule bacteria; nitrogen becomes available as plant matter decomposes. | Planting window varies by species and region; hairy vetch and some clovers need particular attention. | Plan the end date around the next vegetable crop; species and growth stage affect management. |
| Grasses and cereals: rye, oats, wheat | Soil cover, biomass, and nutrient scavenging. | Winter survival varies by crop and location. In New Hampshire, rye is winter-hardy and oats may winter-kill. | Rye allowed to grow late into spring can be difficult to terminate, according to New Hampshire guidance. |
| Brassicas: radishes, turnips | Leafy cover, nutrient uptake, and taproots that may help address compacted layers. | Fit the crop to the local planting window and vegetable rotation. | End growth in time for the next crop and account for potential pests affecting related vegetables. |
Choose by goal, season, and next crop
Start with the job you most want the cover crop to do, then check whether the calendar and bed rotation make it practical.
- For nitrogen contribution: consider a legume, while allowing time for its plant matter to decompose.
- For soil cover and biomass: consider a cereal or grass, matching its winter survival and growth period to your location.
- For nutrient scavenging or taproot growth: consider a brassica, provided it fits your rotation for cabbage-family crops.
- For weed suppression in a warm-season window: buckwheat is an additional fast-growing broadleaf option, though it is not one of the three groups above.
Also account for how long the bed can remain occupied and how much management you can handle. A mixture—for example, a cereal with a legume—can combine functions, but species may have different planting dates and growth habits, making the mix harder to establish and terminate. A single species can still offer useful benefits. [UNH Extension] [University of Vermont Extension]
Rank #4
- VERSATILE & NUTRIENT-RICH COVER CROP Seed MIX: Our Gardenway cover crop seeds include a diverse blend of triticale, pea seeds, oats, hairy vetch seed, annual rye grass seed, crimson clover seeds. These nutrient-rich seeds enhance soil health and fertility, making them ideal for various gardening applications such as vegetable gardens, flower beds, and home lawns.
- EASY TO GROW & LOW MAINTENANCE: Our gardenway cover crop seeds are easy to plant and cultivate, suitable for gardeners of all skill levels. Their resilient nature ensures successful growth even in challenging conditions. These low-maintenance seeds reduce the need for intensive care, making gardening easier and more enjoyable.
- IMPROVES SOIL HEALTH & WATER RETENTION: Our cover crop seeds enhance soil health by fixing nitrogen, and improving soil structure. This leads to healthier, more fertile soil that supports robust plant growth. Additionally, they improve soil water retention, reducing the need for frequent watering and maintaining moisture levels during dry periods.
- PREVENTS SOIL EROSION & CONTROLS UNWANTED VEGETATION: Our mixed plants seeds provide effective ground cover that prevents soil erosion by protecting the soil surface from wind and water erosion. They also control unwanted vegetation by creating a dense cover, reducing the need for herbicides and manual weeding, thus promoting an efficient and greener gardening approach.
- ATTRACTS POLLINATORS & ENHANCES GARDEN BIODIVERSITY: Our cover crop mixed seeds includes flowering plants that attract pollinators like bees and butterflies, enriching biodiversity and improving pollination for other plants in your garden. These seeds naturally improve soil health, reduce the need for chemical inputs, and support better gardening practices, promoting a thriving garden environment.
Prepare a small bed and establish the crop
For a home garden bed, a rototiller is not essential. UNH Extension advises lightly scratching the surface with a rake or hoe, then firming seed for good soil contact. Sowing too late can leave plants too small to cover the soil or establish roots adequately. Its planting dates apply to New Hampshire; use local guidance for other regions. [UNH Extension]
Plan termination before you sow
Decide how you will stop growth and when the bed must be ready for vegetables. Depending on the crop and your setup, options include cutting, mowing, or tarping. Prevent unwanted reseeding, and leave whatever interval your local, species-specific guidance recommends before planting vegetables; there is no single gap that fits every crop and region. [UNH Extension] [University of Minnesota Extension] [University of Vermont Extension]
Quick wins for a faster PC:
Clear out junk files and repair common Windows errorsFree Scan →Scan for outdated or missing drivers - takes under a minuteDriver Scan →Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
