The Master Gardener Program of San Diego maintains a page devoted solely to grants available to school gardens. It is updated regularly and has become an invaluable resource for school gardens and green spaces throughout the United States, not just San Diego or California.
While you are at the site check out some of their other resources, such as this pdf handout, Vegetable Garden Basics and this recent newsletter article about growing Cameliia sinensis (the tea tree) in your own back yard or on a patio.
