Green manure crops can help to control weeds and protect your garden’s soil. Sun and heavy rains can compact soil and leach out beneficial nutrients. When green manure crops are dug in to the garden at the end of their growing season, they add organic matter, nitrogen, and minerals that are brought up by the roots.
When choosing the best type of cover crop for your situation, you need to consider your climate, soil type, the duration needed and whether you want a nitrogen-fixing crop or a crop that produces a lot of organic matter to dig back into the soil.
Deep-rooting plants can break up the sub-soil and bring up trace minerals that are deep in the soil. Alfalfa and red clover are good examples of such deep-rooting plants. These are also good cover crops if you’re not planning to plant in that bed or field for a longer period as they can grow for a year or more. Broad beans are excellent for breaking up heavy soil, and they grow well in the colder months. Not only do they fix nitrogen into the soil, they have the added bonus of being edible – a delicious treat in the spring.
Buckwheat is a good cover crop for areas where you plan to plant again soon, as it grows very fast and breaks down quickly. Rye, barley or wheat can be used to help suppress weeds. They are rich in organic matter, and can be dug in early or left longer.
Lupines are a great cover crop if you want something that fixes nitrogen, is fast growing, breaks down quickly when dug in and has beautiful flowers as an added benefit. Another beautiful flower is Marigolds, which are a good cover crop in the summer as they help repel nematodes that live in the soil and eat the roots of plants. They are also great as a companion plant, especially for tomatoes.
