A San Francisco church has partnered with a local nonprofit to promote "edible rooftops." A garden on the roof of Glide Memorial Church produces kale, turnips, radishes and other winter crops. The partnership aims to inspire residents to create similar gardens on their roofs. The garden is made of reused materials and puts little pressure on the roof of the church. The green roof industry surged about 200% between 2004 and 2007 and is a $12 billion market.