One of the easiest and most effective cover crops to plant in your garden in the fall is "Annual Rye Grass". It grows in a relatively short time and is so easy to plant. It's a seed that you basically "throw it on and let it grow"! It will grow fast in the late fall and winter when the garden is idle. Besides the abundant top growth, it produces incredible quantities of small hair roots which break up the soil, decompose quickly and add humus to the soil. Just till it into the soil in the spring!