Green Roofs Growing over American Cities

Annie Novak has farmed in nine different countries, but never on a farm that required climbing on a flight of stairs.

Her 6,000-square-foot organic farm is on the roof of a warehouse in Brooklyn.

"We're already growing our fall squashes, and we're saying goodbye to our summer fruits," Novak said.

Started in April, it is the nation's first commercial working farm built on a green roof. The owners grow and sell more than 30 varieties of fruits and vegetables to local restaurants and residents.

But besides the food, green roofs offer big environmental benefits, reports CBS News correspondent Hari Sreenivasan. The soil on this roof can absorb up to two inches of rain, preventing rainwater from picking up pollutants on the ground before it enters storm drains.

"When it goes out the drain, it hits a very antiquated sewage system that when it's overtaxed just pumps everything out into the ocean," Novak said.

Lisa Goode, who designed this farm and builds green roofs for homes and office buildings, says they reduce utility bills.

"This basically acts as an air conditioner for the heat that rises through a building," Goode said.

The soil and plants also save owners money by extending the life of roofs.

"You're protecting your roof, because you're removing it from UV rays and ice and cold," Goode said.

Green Roofs: Doing it Bigger, Better

While this rooftop farm in New York is exceptional, it is not unique. There are green roofs sprouting up all over the country.

Green roofs on top of both Chicago's city hall and San Francisco's California Academy of Sciences keep the buildings 10 degrees cooler in the summer and that much warmer in winter. A hospital in Green Bay, Wis. and a firehouse in Raleigh, N.C. just installed green roofs. The two-and-a-half acre green roof on the Target Center Arena in Minneapolis will keep a million gallons of storm water from flowing into the Mississippi River every year. And you might be surprised to learn that one of the largest green roofs in America was build "Ford tough" on top of a truck plant in Dearborn, Mich.

Annie Novak hopes her Brooklyn farm doesn't remain the only green roof in the neighborhood for long.

"The more the merrier," Novak said. "We need this in this city."