A green lawn is as American as apple pie, and for many of us, just as comforting. But as more people move to urban areas, lawns and other manicured spaces are beginning to dominate the landscape. Lawns already cover more land in the United States than any other irrigated crop, and a lawn in Phoenix looks much like a lawn in Boston. Why do we love lawns so? How do they impact the environment? And what could we do differently? Soil scientist and urban ecologist Peter Groffman joins us to discuss. Groffman has studied the ecology of Baltimore and other cities for decades, including their lawns.