Mah Bow Tan, a member of Singapore's Parliament, inspects Chinese cabbage growing at the commercial vertical farm. Troughs of the veggies stack up to 30 feet in the greenhouse. Courtesy of MNDsingapore. hide caption

itoggle caption Courtesy of MNDsingapore.

Guerrilla grafter Tara Hui grafts a fruiting pear branch onto an ornamental fruit tree in the San Francisco Bay Area. She doesn't want the location known because the grafting is illegal. Lonny Shavelson for NPR hide caption

itoggle caption Lonny Shavelson for NPR