Sasha CampbellCover crops are one of the easiest natural ways to improve your soil, reduce weeds, and protect your garden. Gardeners have used them for thousands of years [1].
Cover crops are fast-growing plants grown to protect and improve the soil. When they are cut and worked into the soil while still green, they are called green manures.
They also help prevent soil erosion while providing grazing and fodder for farm animals.
Main Benefits of Cover Crops
Cover crops offer many benefits, but their main job is to improve and protect the soil.
- Help stop weeds by blocking sunlight.
- Add nitrogen to the soil (legumes only).
- Loosen hard soil with their roots.
- Help the soil hold more water.
- Protect soil from erosion.
- Add organic matter as they break down.
- Improve soil health for future crops.
- Some cover crops can also be grown as living mulch between vegetables.
When to Plant Cover Crops
Most cover crops are planted after you harvest your vegetables or before you plant a new crop. Some grow best in summer, while others are planted in fall to protect the soil through winter.
Cover Crop Examples
Cover crops fall into four classes: grasses, legumes, brassicas, and non-legume broadleaves.
Grasses
Grasses are excellent cover crops because they protect the soil and reduce erosion.
They help trap leftover nitrogen in the soil, reducing nutrient loss. After they are cut, the leftover stems and leaves form mulch that protects the soil as they slowly break down.
This category includes rye, oats, wheat, barley, and annual ryegrass.
Legumes
Legumes are good cover crops grown because they enrich the soil with nitrogen. They take nitrogen from the air and add it to the soil with the help of bacteria on their roots.
Living plants provide organic matter, attract pollinators, and bring in helpful insects. They also help to stop soil erosion.
Examples include white clover, hairy vetch, field peas, sweet clover, and alfalfa.
Brassicas
This category includes the eye-catching yellow fields of rapeseed and mustard. These cover crops are generally cultivated to prevent fall erosion and help with pest management.
Radishes and turnips are other examples. Both have many valuable properties.
Some brassicas can also help reduce certain soil pests and diseases.
Non-Legume Broadleaves
These crops produce green manure, recycle existing soil nitrogen, and help hold the soil in place. However, they cannot fix atmospheric nitrogen.
Non-legume cover crops include flax, buckwheat, and phacelia.
Summer Cover Crops
The best summer cover crop depends on your climate and your garden goals.
Generally, buckwheat, cowpeas, and sorghum-sudangrass are excellent summer cover crops. Sunn hemp is another good choice in warm climates.
Winter Cover Crops
Many cover crops grow well through winter and protect the soil until spring.
Good winter cover crops include crimson clover, winter rye, hairy vetch, Austrian winter peas, and winter wheat. Crimson clover is popular because it adds nitrogen and attracts pollinators.
You can also grow winter wheat in any suitable environment. In spring, winter wheat can be cut before it produces seed and worked into the soil.
Winter-Killing
Some cover crops die naturally during freezing weather. Their dead leaves and stems form a protective mulch that helps prevent erosion and improves the soil as they break down.
Cover crops that do not die naturally can be cut or mowed in early spring before planting.
Cover Crops on Farms
Sowing cover crops for grazing farm animals has many benefits. It is an affordable way to feed livestock while still protecting the soil.
Cover plants for grazing include cereal grains like wheat, oats, barley, and millet. Additionally, legumes include alfalfa, peas, beans, and clover.
Specific Uses of Cover Crops
Establishing planting objectives (buy seeds here) can help you select the right plants.
Nitrogen Fixation
Legumes such as cowpeas, velvet beans, hairy vetch, and clovers fix nitrogen in the soil. Cabbage and other brassicas also require a lot of nitrogen, so planting legumes first is beneficial.
Tomatoes are heavy feeders and benefit from nitrogen left behind by legumes.
Moisture Improvement and Retention
Clover, rye, and winter wheat cover the soil, helping it hold moisture and reducing evaporation.
Reducing Compaction of the Soil
Turnips, radishes, canola, and sunflowers have deep roots that help loosen hard, compacted soil.
Weed Control and Fast-Growing Cover Crops
Oats, red clover, and buckwheat grow quickly and help crowd out weeds.
Residue Cycling
Brassicas, such as radishes, turnips, rapeseed, and mustards, are best for this. Most brassicas break down quickly after they die, returning nutrients to the soil.
Tender plants like buckwheat break down quickly after they are cut, while high-carbon plants like sorghum take longer to decompose.
Long-Period Cropping
Mixing small grains, such as barley or rye, with legumes, such as vetch, clover, or cowpeas, helps to improve soil health.
Home Gardening
Growing cover crops at home is easier than many gardeners think. After getting your seeds, start with something like buckwheat.
Buckwheat grows quickly in warm weather and can cover bare soil in just a few weeks. It swiftly chokes out weeds. The tiny white flowers attract bees, butterflies, and other helpful insects.
Easily killed and incorporated into the soil, buckwheat plants break down quickly, adding organic matter. For the home garden, you can also experiment with annual ryegrass.
How to End a Cover Crop
Cut or mow most cover crops before they flower or produce seeds. This keeps them from spreading and allows them to break down more quickly, adding organic matter to the soil.
Takeaway
Cover crops are an easy and natural way to build healthier soil.
They help prevent weed growth, reduce erosion, improve soil structure, add organic matter, and retain moisture. Some also add nitrogen to the soil or attract helpful insects and pollinators.
Whether you grow vegetables or flowers, cover crops can make your garden healthier year after year.
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