Cover crops are a great way to add organic matter to your garden soil and crowd out weeds. A cover crop is anything that is planted on a temporary basis. If you till under the cover crop while its still green, its called green manure. A variety of plants can be used as cover crops or green manure depending on your preferences.
Traditionally cover crops are planted in vegetable gardens after the fall harvest. When planted at this time they cover the soil over the winter, reducing erosion by wind and rain and discouraging weeds. They are tilled under the following spring a week or two before planting.
Some cover crops die to the ground over winter and can be left in place to act as a mulch that you plant your transplants right through.
To really improve your soil you can take a section of your garden out of production for a year and plant a succession of cover crops all season long which you turn under as green manure. A good sequence for this program could be to plant oats in May, till them under in late June and plant buckwheat, till that under in early August and plant another crop of buckwheat, till that under in mid September and plant oats or winter rye that will stay over the winter. The following spring you till that under and are ready to plant your garden. Youll be amazed by the improvement in your soil from this intensive program.
Rather than giving up your whole garden for a year you can follow this procedure with just one section of your garden one year, then another section the following year. This is an excellent way to really improve your soil while still having a garden.
The two most common fall cover crops are oats and winter rye. Oats come up quickly and die with the first really hard frost. Their debris is easy to till under next spring. Winter rye loves cool weather and can be planted until early October. It over winters and turns green in early spring, producing lots of green manure for your soil. Youll need a rototiller to till it under unless the area is very small.
Buckwheat needs warm temperatures to grow well so its only planted in the summer months. White clover takes a while to get established so this is used as a cover crop only where it can be left to grow for at least a full year before being tilled under.