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Cover crops can improve garden soil in different ways: legumes such as clover, peas, and vetch can add nitrogen to the crop cycle, while grasses and other plants capture nutrients, protect bare ground, suppress weeds, or help improve soil structure. The right choice depends on what your bed needs and when you can plant and cut it back.
How plants enrich soil
Cover crops are plants grown between food crops or during otherwise bare periods. Some legumes work with Rhizobia bacteria in root nodules to convert atmospheric nitrogen into a plant-usable form. That nitrogen becomes available to later crops as roots and plant residues decompose; it is not an instant fertilizer for nearby plants.
Non-legume covers contribute differently. Their roots can capture nutrients already in the soil that might otherwise leach away, and return them as plant material breaks down. Living roots also anchor soil, while dense growth can protect the surface and suppress weeds. Decomposing residues feed soil organisms and add organic matter.
Eight plants to consider
1. Crimson clover
This cool-season legume is a strong nitrogen fixer when its Rhizobia partnership is working. Its roots can also help reduce compaction and build soil. It is a useful choice when you want a flowering cover and a nitrogen contribution.
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2. White clover
White clover is a perennial legume that can fix nitrogen and help reduce compaction. It can cover bare ground in spring or summer. Because it is perennial, consider whether you want a persistent living cover before sowing it in a bed that will soon be replanted.
3. Field peas
Field peas are a legume cover crop that can fix nitrogen with the right Rhizobia present. They are also used in cool-season mixes. Peas may flower and provide forage for pollinators, but cut the cover before seed develops if you do not want volunteer plants in later crops.
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- Feed the soil not the plants - stimulate microbial activity in your soil and boost probability of success with all types of plants… like composting but faster
- For best results, apply monthly throughout the growing season, especially in the fall and spring
- No synthetic chemicals - main ingredient in this product is activated humics derived from organic sources (OMRI certified organic)
- Concentrated formula - simply dilute at a ratio of 1 oz to 1 gallon and spray/pour on your soil
- Farmer’s Secret products are made with pride in Kentucky and puts the know-how of award-winning farmers into your hands. Get in on the Secret!
4. Hairy vetch
Hairy vetch is a cool-season legume that can contribute nitrogen. Its fall growth is slow, while root development continues over winter. It can suit a garden that needs a winter cover, provided you plan how and when to terminate it before planting the next crop.
5. Fava beans
Fava, or broad, beans are legumes with a taproot that can help open heavy soil. If you harvest the beans, nitrogen is carried away in the seeds; returning foliage and roots to the bed as green manure keeps more plant material in the soil cycle. They can also be grown for edible harvest rather than solely as a cover crop.
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6. Buckwheat
Buckwheat is a fast-growing summer cover crop, not a nitrogen fixer. It attracts pollinators and can move phosphorus from deeper soil into plant material. Cut it before it sets seed if you want to avoid unwanted self-seeding.
7. Winter rye
Winter rye is a cool-season grass that establishes in fall, protects soil, and can suppress weeds. It captures and recycles nutrients already in the soil rather than fixing nitrogen. Its value is especially practical where you want living cover through a bare season.
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8. Forage radish
Forage radish, also called tillage radish, is a brassica with a long taproot. It can scavenge nutrients and may help with infiltration and compaction as roots grow and later decay. Avoid planting it after brassica vegetables such as broccoli: related crops can share pests and diseases.
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- For nitrogen contribution: consider crimson or white clover, field peas, hairy vetch, or fava beans. The benefit depends on functioning Rhizobia and on returning roots or residues to the soil.
- For nutrient capture and winter protection: winter rye can hold nutrients in plant growth and cover the soil. Forage radish can also capture nutrients and contribute a deep-root effect.
- For summer cover and pollinators: buckwheat is a non-legume option; clovers and flowering legumes can also provide forage.
- For edible harvest: fava beans can produce food, but harvesting seeds removes some nutrients that would otherwise remain in the bed.
A mix can combine benefits—for example, a legume with a grass—but choose species that fit your climate, planting window, and next crop. Persistence and ease of termination matter as much as the benefit listed on a seed packet.
Best Value
- Feed the soil not the plants - stimulate microbial activity in your soil and boost probability of success with all types of plants… like composting but faster
- For best results, apply monthly throughout the growing season, especially in the fall and spring
- No synthetic chemicals - main ingredient in this product is activated humics derived from organic sources (OMRI certified organic)
- Concentrated formula - simply dilute at a ratio of 1 oz to 1 gallon and spray/pour on your soil
- Farmer’s Secret products are made with pride in Kentucky and puts the know-how of award-winning farmers into your hands. Get in on the Secret!
Plant and terminate at the right time
Planting and termination dates depend on region. Maryland Extension gives a fall planting example from mid-August through no later than mid-October, with covers commonly mown, flattened, or turned into the soil before setting seed, often in late April or early May. Those are Maryland-specific guide dates, not a universal calendar.
In small beds, cut a cover crop shortly before flowering and do not let it set seed. This limits volunteer plants in the next planting. For legumes, allowing seeds to develop can shift nitrogen into the seeds rather than leaving it in roots and foliage for the following crop.
For peas and beans, crop-specific live Rhizobia must be present for nitrogen fixation. Some seed is already inoculated, so check the seed label before deciding whether a separate inoculant is needed.
Quick Recap
Sources and regional guidance
- USDA Natural Resources Conservation Service: Cover crop guidance
- University of Maryland Extension: Cover crops in gardens
- University of California Agriculture and Natural Resources: Cover crop guidance
- University of New Hampshire Extension: Cover crops for home gardens
- University of Minnesota Extension: Legume cover crops and inoculation
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