One natural way to manage weeds in your garden and improve soil structure is to use cover crops. This method dates as far back as ancient Greek and Roman times .
What are cover crops? These are plants that are planted to cover the soil. They also help to prevent soil erosion, all while providing grazing and fodder for farm animals.
Main Benefits of Cover Crops
Soil improvement is the main aim of planting cover crops.
- 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 deep into the soil.
- They hold the soil in place, thereby preventing soil erosion.
- Green manures add nutrients by increasing soil organic matter.
- If properly managed, garden cover crops can also provide mulching benefits.
- Living mulches also serve as great ground covers.
Cover crops fall into four main categories: grasses, legumes, brassicas, and non-legumes broadleaves.
These are not only useful but are also very attractive plants. For the practical gardener or farmer, grasses and cereals are useful in reducing erosion.
They also work for suppressing weeds and producing residue high in nitrogen. Additionally, the residue left after cutting provides a nutrient-rich mulch that helps protect the soil from adverse weather conditions.
This category includes rye and sorghum grasses plus oats, wheat, and barley cereal crops.
Legumes are good cover crops grown mostly for their ability to enrich the soil with nitrogen. They fix nitrogen from the atmosphere and supply it to the soil.
Additionally, living plants add organic matter, attract pollinators and beneficial predatory insects, and help prevent erosion of the soil.
This group includes clovers, vetches, peas and soybeans, mucuna vine, and alfalfa.
This category includes the eye-catching yellow fields of rapeseed (canola) and mustard. Generally, these are successful cover plants cultivated especially to support growth in vegetable crops.
For example, forage radish has many useful properties. These include root penetration that improves the friability of the soil and nutrient uptake. Turnips and marigolds are other crops in this group.
These broadleaf crops make green manure, recycle existing soil nitrogen, and bind the soil together. However, they cannot fix nitrogen from the atmosphere.
Species include buckwheat, annual ryegrass, cereal rye, and barley.
Crop monitoring will help determine which cover plant or group suits the specific needs and conditions for vegetable gardens.
In general, those most suitable for summer growth are buckwheat, cowpeas, sorghum-sudangrass, and wheat.
Winter Cover Crops
Winter conditions can badly affect some crops like canola. Others, however, like clovers, especially crimson clover, annual rye, some vetches, and Austrian peas are suitable. Moreover, clover is an edible weed.
You can grow winter wheat in any suitable environment. After producing a beneficial greensward in early spring, they can be killed off and tilled in to enrich the soil for the summer crops.
Experienced gardeners will know exactly the right moment when the growing benefits of these crops have reached their peak and are going to seed. This is the time to kill off the plants.
Crops that naturally die of 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.
Crop residue, depending on the type, may be tilled in to enrich the soil. Mowing is the most common method of crop kill. However, a labor-saving useful way is to allow animals to graze.
Benefits of 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 by 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 clovers.
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. Cabbage and other brassicas 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. Oats and red clover or quick-growers like buckwheat.
- Residue cycling. The brassicas are best for this, e.g. radishes, turnips, rapeseed, and mustards. Most brassicas are winter-killed, providing nitrogen-rich residue. Tender plants like buckwheat will rot down. They are then absorbed into the soil speedily but others like carbon-producing sorghum take longer.
- Long-period cropping. Mixes of small cereal grains like barley or rye with nitrogen-fixing legumes such as vetch, clovers, or cowpeas.
This method practiced on a small scale need not be daunting. Start with something like buckwheat. Easily sown and fast-growing, buckwheat thrives well in moist and cool conditions.
Moreover, it rapidly smothers weeds and the small white flowers attract beneficial predatory insects and pollinators like bees and butterflies.
Easily killed and incorporated into the earth, buckwheat leaves valuable nutrients for soil enrichment.
For the home garden, you can also experiment with annual ryegrass.
The use of cover crops has a central place in agriculture. Sown in rotation throughout the year, these crops are grown to repair and/or enrich soils. They do so by improving the structure and imparting nitrogen, carbon, and other nutrients.
Moreover, they are effective in increasing and retaining moisture, suppressing weeds naturally, and preventing soil erosion. Some are also great at attracting pollinators and beneficial insects.