They can be used small (just as the pods begin to fill) as you would green or snap beans. They are primarily used as a green shelled bean and cooked in salted water. As a dry bean, they can be harvested as the pods begin to turn black.
Favas prefer well drained, fertile soil and do not do well in hot weather. They are typically planted in fall or winter and finished by early summer. As a rule of thumb, plant them and grow in the same time period as you would English or garden peas. Plant in blocks, or two to three rows together, to help prevent the plants from falling over.
Some people cook the upper leaves of the plant like spinach. It should be noted that some people may have an allergic reaction to uncooked fava beans. The presumed toxins are eliminated by cooking.
Although they have been in cultivation in many parts of the world for centuries, favas are relatively new to the North American farm, garden and market.