Ron Finley gives a terrific TED Talk about his work planting gardens in the food desert of South Central Los Angeles. It is really worth a watch (it's only 10 minutes). He became a gardening renegade after the city tried to make him take out the vegetable garden in his planting strip.
"To change the community, you have to change the composition of the soil. We are the soil… Gardening is the most therapeutic and defiant act you can do. Especially in the inner city. Plus you get strawberries."