Thanks to the Neighborhood Farm Initiative for this Google map of community gardens:

The DC Government lists community gardens within the city here.

Washington Gardener Magazine provides this listing of DC-area community gardens.

A Community of Gardeners is a one-hour documentary by local filmmaker Cintia Cabib, exploring the vital role of seven community gardens in Washington, D.C. as sources of fresh, nutritious food, outdoor classrooms, places of healing, links to immigrants’ native countries, centers of social interaction, and oases of beauty and calm in inner-city neighborhoods. The film also traces the history of community gardens in the U.S., from the potato patch farms of the late 19th century, to the victory gardens of World War II, to community gardening’s current renaissance. A Community of Gardeners has aired on PBS, screened at numerous venues throughout the U.S., and is available for purchase.

Need space to garden? There’s another option - Sharing backyards DC.