Cover Cropping in the Organic Garden

When growing organically, it is important to realize that the organic method is a balancing act between positive and negative factors in nature. When this balance gets out of order, pests and plant diseases begin to invade your garden. Most inexperienced gardeners reach out to chemical fertilizers or pesticides to alleviate the problem because he/she feels overwhelmed.

When you devote yourself to growing organically, you must realize that the soil is a living creature. Soil is filled with beneficial nematodes, fungi, and bacteria that convert soil nutrients and package them into a usable form. Healthy soil will contain organic material in various levels of decay. One of the ways used to maintain healthy soil is through the practice of cover cropping.

Cover crops are usually planted in late summer/early fall or early spring and contain two components: a nitrogen fixer/scavenger and a carbon fixer/scavenger. Legumes, such as crown vetch or hairy vetch fix nitrogen in the soil when bacteria on the roots of these plants fix atmospheric nitrogen gas into nitrate or nitrite.

Grasses, such as rye, clovers, oats, and winter wheat send down long roots into the soil to scavenge nutrients down in the deeper levels of soil where most plant's roots don't typically reach. After these "cover crops" are allowed to grow for a few months they are either tilled into the soil or chopped up and allowed rot on the surface of the soil. This is compatible with the no-dig method or organic gardening.

When these crops begin to break down in the soil, the roots release phosphorus and the grass blades and legumes provide a boost of nitrogen and carbon that is time-released into the soil throughout spring and into summer. This grass/legume combination is also beneficial because legumes need a "trellis" to grow up (think of pea fencing) and grasses provide this service for the legume.

Cover crops are also beneficial because they keep the soil loose and prevent erosion. Some legumes are planted and left in the garden all summer long to provide a living mulch. This keeps moisture in the garden bed while developing seedlings are beginning to grow.

When growing organically, the cover crop should be the single most important way of managing nutrients in the soil. You will not only see a benefit in the production of vegetables and fruit but there will also be a noticeable difference in soil health and fertility.