THIS summer, Tony Tomelden hopes to be making bloody marys at the Pug in Washington, D.C., with tomatoes and chilies grown above the bar, thanks to the city’s incentives for green roofs.

Aeries are cropping up on America’s skylines, filled with the promise of juicy tomatoes, tiny Alpine strawberries and the heady perfume of basil and lavender. High above the noise and grime of urban streets, gardeners are raising fruits and vegetables. Some are simply finding the joys of backyard gardens several stories up, others are doing it for the environment and some because they know local food sells well.