Amidst the hustle and bustle, few would guess that sitting high above rush hour traffic are full-production organic farms growing food in only eight to twelve inches of soil on the rooftops of New York City buildings. We visit two such one-acre farms to learn how they are creating a whole new model for locally-grown urban food. But their sky-high gardening techniques aren't exclusive to the Big Apple; they share secrets for duplicating their results anywhere in the world.