If you didn't plant a cover crop last fall, you can still sow cowpeas, buckwheat, oats, or alfalfa in the early spring. They require a little extra work, but cover crops help hold the soil while the garden is idle and keep it from washing away. They also help pump life back into tired soils.

When it's time to cut, use a lawnmower or a string trimmer to remove the top growth of your cover crop before you till. If you don't, your tiller will likely become tangled in green stems and leaves, making the job difficult, if not impossible. Some gardeners prefer to cut their cover crop and let it lie on the ground and wilt a few days before turning it under.

Turn your garden thoroughly, mixing all the green vegetation evenly into the soil. You can use a turning fork if your garden is small. Don't till when the soil is wet and tacky or if it's extremely dry. The ground should just be slightly moist. It will take the masses of green manure a few weeks to break down, but the process eventually increases the amount of organic matter in the soil. Cowpeas, vetch, soybeans, and some of the clovers are legumes that have the ability to take nitrogen from the air and store it in their roots. The nitrogen will then be available to future crops.