Sasha CampbellOne natural way to manage weeds in your garden and improve soil structure is to use cover crops. This method dates back to ancient Greek and Roman times [1].
Cover crops (green manures) are fast-growing plants grown to be incorporated into the soil while still green. They also help prevent soil erosion while providing grazing and fodder for farm animals.
Main Benefits of Cover Crops
Soil improvement is the main aim of planting cover crops in gardens.
- Weed suppression. These plants can block sunlight, smothering weeds.
- Legume cover crops recycle and add nitrogen to the soil.
- Aeration is a further benefit, preventing the soil from compacting and allowing other plants to thrive.
- Conserve soil moisture. Cover crops trap water, allowing it to filter deeply into the soil.
- They also hold the soil in place, thereby preventing soil erosion.
- Green manures add nutrients by increasing soil organic matter.
- If adequately managed, garden cover crops can also provide mulching benefits.
- Living mulches also serve as great ground covers.
Cover Crop Examples
Cover crops fall into four classes: grasses, legumes, brassicas, and non-legume broadleaves.
Grasses
These are not only useful but also very attractive plants. For the practical gardener, grasses are annual cereals that hold the soil in place, thus reducing soil erosion.
They also suppress weeds and accumulate soil nitrogen. The residue left after cutting provides a nutrient-rich mulch that helps retain soil moisture.
This category includes rye, corn, oats, wheat, and barley.
Legumes
Legumes are good cover crops grown because they enrich the soil with nitrogen. They fix nitrogen from the atmosphere and supply it to the soil.
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. They help suppress the growth of weeds and may also help control fungal issues.
Non-Legume Broadleaves
These crops make green manure, recycle existing soil nitrogen, and bind the soil together. However, they cannot fix nitrogen from the atmosphere.
Non-legume cover crops include flax and spinach.
Summer Cover Crops
Crop monitoring helps find the best cover plants for your vegetable garden.
Generally, buckwheat, cowpeas, sudangrass, and wheat are the most suitable for summer growth.
Winter Cover Crops
Winter conditions can badly affect some crops, like canola. Others, however, like crimson clover, winter rye, hairy vetch, and Austrian peas, are suitable. Moreover, clover is an edible weed.
You can also grow winter wheat in any suitable environment. After producing in the early spring, it can be killed off and tilled in to enrich the soil for the summer crops.
Winter-Killing
Experienced gardeners will know exactly when these crops’ growing benefits have reached their peak and are going to seed. This is the time to kill the plants.
Crops that naturally die from the cold form a nutritious surface mulch that protects the ground from erosion. Moreover, those that are winter-killed by other means can leave the ground free for early spring.
Depending on the type, crop residue may be tilled in to enrich the soil. Mowing is the most common method of crop-killing. However, allowing animals to graze is a labor-saving and helpful method.
Planting for Grazing
Sowing cover crops for grazing farm animals has many benefits. It is primarily a cost-effective way of feeding livestock.
In turn, grazing animals help reduce soil compaction through their movements. Moreover, dung helps increase soil organic matter.
Cover plants for grazing include cereal grains like wheat, oats, barley, and millet. Additionally, there are legumes such as alfalfa, peas, beans, and clover.
Specific Uses of Cover Crops
Establishing objectives when planting (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 also absorb a lot of nutrients and benefit from the prior planting of nitrogen fixers.
Moisture Improvement and Retention
Crimson and white clovers, winter wheat, rye, and rapeseed.
Reducing Compaction of the Soil
Turnips, radishes, canola, and sunflowers.
Weed Cover and Short-Term Cropping
These include oats, red clover, or quick-growers like buckwheat.
Residue Cycling
Brassicas, such as radishes, turnips, rapeseed, and mustards, are best for this. Most brassicas are winter-killed, providing nitrogen-rich residue.
Tender plants like buckwheat will rot down. They are then absorbed into the soil quickly, but others, such as carbon-producing sorghum, take longer.
Long-Period Cropping
Mixing small grains like barley or rye with legumes such as vetch, clover, or cowpeas helps improve soil health.
Home Gardening
This method, practiced on a small scale, need not be daunting. After getting your seeds, start with something like buckwheat.
Easily sown and fast-growing, buckwheat thrives in moist and cool conditions. It swiftly chokes out weeds. The tiny white flowers also attract beneficial insects, including bees and butterflies.
Easily killed and incorporated into the soil, buckwheat leaves valuable nutrients for enrichment. For the home garden, you can also experiment with annual ryegrass.
Takeaway
The use of cover crops is central to agriculture. These crops are grown to repair and/or enrich soils. They do so by improving the structure and influencing the amount of nitrogen and other nutrients.
They also help keep moisture, fight weeds, and stop soil erosion. Some are also great at attracting pollinators and beneficial insects.
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