Fava beans are known by many names, including Vicis faba, horse beans, Windsor beans, pigeon peas, bell beans and silkworm beans. They are native to the Mediterranean area.
Although they're called a bean, they are related to vetch, in the pea plant family. The plants produce a bean that is the same approximate size as lima beans. The beans are tasty, but a primary use of fava beans is as a "green manure" that you can grow in your garden in fall and winter and then dig under to give your soil nitrogen and other nutrients.
Prepare your planting area by digging compost into the soil. Any type of compost, well-rotted animal manure, grass clippings, fallen leaves, last summer's chopped-up vegetable plants and other plant materials are appropriate soil amendments. Rake your planting area level.
Plant fava bean seeds directly into your garden in September through November if you plan to use them as a cover crop. Make rows two to three feet apart. Dig small holes in the center of your rows one to two inches deep and four to five inches apart, and then insert one seed into each hole. Water the area if fall rains have not yet begun and your soil is dry: set a sprinkler on the area for up to one hour after planting.
Thin young plants to eight to 10 inches apart when they are about two inches tall. Select the strongest, healthiest looking plants and pull the weaklings. The plants you pull make a good addition to your compost pile.
Fertilize your beans with a low nitrogen fertilizer one month after planting seeds. Because they are nitrogen-fixing legumes, they do not require additional nitrogen.
Control aphids and bean weevils if they should appear on your fava beans. Introduce ladybugs to control aphids or spray your plants every other day with insecticidal soap. Bean weevils are small beetles---they are shaped like a triangle and are a dull color with red, black or white markings. Hand-picking bean weevils is the only reliable method of controlling this pest because treating fava beans with insecticide has not shown good results in University of California at Davis field trials.