Although its roots stretch back to the concrete labyrinth of NYC in the 1970s, guerrilla gardening (the practice of clandestinely farming land that one does not own) has lately taken on special poignancy in London. With food prices climbing and open space at a premium, guerrilla gardeners grow beets in local roundabouts, plant trees within construction sites and harvest corn in the park. Tonight, Richard Reynolds, the man behind London's burgeoning guerrilla-gardening scene, talks about the movement's political and environmental implications and gives green-thumbed radicals tips on how to start revolutions in their own neighborhoods.