The benefits of building your soil
Seasonal vegetable gardens can quickly deplete your soil of its nutrient resources. Soils with low nutrient levels produce low vegetable yields. Planting a cover crop during the winter is an easy and affordable way to add nutrients back into your soil. In addition to enriching your soil, cover crops afford a number of other benefits including the creation of a natural weed barrier, reducing erosion from winter rains, and increasing the soil’s capacity to hold water. By incorporating a cover crop into the soil, you will greatly improve its structure as the decomposing organic matter increases the air space between soil particles.
Any garden can benefit from the use of a cover crop. Which cover crop you choose will depend on the specific needs of your garden.
Annual Ryegrass — Ryegrass is quick to germinate and is very vigorous. It grows well in our Bay Area clay and can tolerate wet soil. In the spring, mow or till it under, then the residue breaks down quickly adding needed organic material to improve soil structure and drainage.
New Zealand White Clover — An excellent perennial cover crop. Plant along with turf or other perennials as a long-term nitrogen and phosphorus supplement.
Crimson Clover — Fixes up to 150 lbs. of nitrogen per acre. It also increases the availability of phosphorus, actively suppresses weeds, and attracts beneficial insects.
Winter cover crops should be planted during the fall or early winter. Incorporate cover crops into the ground at least one month before you intend to plant your garden. This will allow your garden maximum accessibility to its new soil resources.