 Whether you need a hammer or a house, go check them out today. To see everything they have to offer, visit rbclisbon.com. Rooftop farms are gaining popularity in Washington, D.C. Christoph Grinna, the co-founder and manager at Uptop Acres, says his goal is to restore nature and cities, and they do this by establishing gardens on top of commercial buildings. He says there's a lot of rooftop space in the city that could be put to use.