Best Cover Crops for Your Garden Explained

Cover crops do more than help with soil erosion and weed control. They also help to put nutrients and organic matter back into the soil as well as help with weed and pest control. The best cover crops for winter gardening are those that add nitrogen and nutrients to the soil. These include cereal grains like oats, barley, and rye.

Growing a cover crop in your garden will improve the soil by adding organic matter to the soil which decomposes, but the organic matter can also feed earthworms. Their casting has higher levels of nitrogen, nutrients, and a neutral pH level, as well as beneficial microbes that help plants to fight diseases.

Cover crops can also be used in containers or raised garden beds. A diverse cover crop is essential to the never-ending task of soil management. Remember that each type of crop has a purpose. Legumes fix nitrogen to the soil, grasses aerate the soil, and brassicas plants prevent pathogens and improve the structure of the soil.

To keep your soil in the best possible condition you can plant a cover crop after you have harvested the main crop. Depending on the main crops being grown at the time, some cover crops can be planted to speed up the improvement of the soil.

Key Takeaways

• Cover crops improve soil by adding organic matter, nutrients, and controlling erosion and weeds
• They can be used in traditional gardens, containers, and raised beds
• Main types of cover crops include legumes, grains, and brassicas, each serving different purposes:
• Legumes (e.g., hairy vetch, clover) fix nitrogen in the soil
• Grains (e.g., oats, rye) improve soil aeration and water retention
• Brassicas (e.g., mustard, radish) control pests and improve soil structure
• Buckwheat is a fast-growing summer cover crop that attracts pollinators
• Alfalfa adds nitrogen and creates deep channels for water penetration
• Radishes, especially oilseed varieties, reduce soil-borne pests and recycle nutrients
• Cover crops can be planted after harvesting main crops to maintain soil health
• Different varieties within each type offer specific benefits and suit various climates

LEGUMES

Cover crops that contain legumes fix nitrogen and improve the soil. A chemical reaction happens because of the Rhizobia bacteria in the nodules of the roots.

For this process to take place, the legumes must have a healthy root system and be well-established to fix nitrogen in the soil which takes several weeks to happen.

Seedlings tend to use more nitrogen than they fix in the soil, therefore it is recommended to start the seedlings indoors and transplant them after three to four weeks.

Soil bacteria and legumes work together to convert atmospheric nitrogen into ammonium and the plants then use the nitrogen to produce proteins.

VARIETIES OF LEGUMES

• Hairy Vetch
• Austrian winter pea – also known as field peas.
• Blackeye peas – also known as cowpeas.
• Red Clover
• Crimson Clover

GRAINS

Growing cereal grains can significantly improve soil aeration as well as water retention.

When the soil becomes too compacted it will make it harder for seedlings to establish a good root structure.

A soil compaction test can be done by digging a hole and looking at the soil, if you see layers, then your soil is too compacted.

These grains have a high aeration rate due to their wide roots and low starch content. These types of grains are ideal for any home gardener and should be a part of any cover crop.

This is because they can grow in a variety of soil types, they can tolerate light frosts, and their roots and stalks are high in carbon and are turned back into the soil in the spring.

VARIETIES OF GRAINS

• Oats
• Barley
• Winter rye – the hardiest grain for growing in winter.
• Winter wheat
• Triticale

ALFALFA

Alfalfa is a great cover crop that fixes nitrogen to the soil and nutrients to it as well. It also prevents soil erosion and loosens the soil below the upper surface without turning the soil over.

Their roots grow 9 to 16 feet deep creating channels for water to get deep into the ground which makes for great compost in your garden soil.

The roots of alfalfa create natural chemicals that make the best environment for microorganisms around the root system.

These microorganisms in turn improve the soil making for an optimal growing medium for the next year.

Alternatively, alfalfa pellets can be purchased, soaked overnight, and added to your garden or compost pile. It will decompose quickly as a plant or as pellets.

With over 4,000 species in this family of nutrient-rich plants, they contain glucosinolates that interfere with the life cycle of fungi and nematodes when tilled into the soil.

Within this family of plants are radishes which work great to break up compacted soil and provide phosphorus and potassium when they are left in the soil to decompose.

PLANTS IN THE BRASSICACEAE FAMILY

• Mustard
• Cabbage
• Napa Cabbage
• Kale
• Broccoli
• Cauliflower
• Radish
• Turnip
• Watercrest
• Wasabi
• Arugula
• Collards
• Rapeseed

ARUGULA

The seeds can be scattered over the garden to provide enough ground cover and weed control.

Arugula produces a large amount of biomass that helps to keep the weeds down

It can also be used as a companion plant with asparagus for example to keep weeds down.