Urban farming is a growth industry in New York city's concrete jungle, and with little open land free agriculturalists and beekeepers have taken to the rooftops to pursue their passion.

Rooftop beekeeper Andrew Cote gets stung by a bee while checking one of his beehives on a rooftop in New York, April 16.

Andrew Cote uses the emergency fire ladder to climb up to the roof of his East Village building, where he tends to 250 bee hives.

Cote, a professor of Japanese literature doubles up as president of the New York City Beekeepers Association, and is happy that the city authorized beekeeping in mid-March after an 11-year ban.

"The city wants to plant one million trees, and the trees need to be pollinated," Cote told AFP.

The ban forced beekeepers into hiding, fearing a 2,000 dollar fine if caught. Now Cote believes the bees are vital to helping keep the city green.

"Our bees pollinate, and they clean the air. It is a way to connect with nature," he said.

Bees also produce around 100 pounds of honey per hive per year, he said -- honey that he sells at the city's various farmer's markets.

Cote said he has received several requests to install rooftop beehives, and the demand is such that on Sunday he is scheduled to offer a course for aspiring apiculturalists.

On the other side of Manhattan, in the posh Upper East Side, Eli Zabar, owner of the upscale "Vinegar Factory" delicatessen, inspects the crops he is growing on the roof of the old factory bought in 1991.

"I began the green houses 15 years ago," Zabar told AFP. "I grow heirloom tomatoes, lots of different kinds of lettuce, herbs, basil, rosemary, thyme, raspberries, figs, beets. We use the heat of the bakeries and pastries, we recycle the heat. With the use of the heat we have eliminated our (carbon) footprint.

"You harvest in the morning, you sell in the afternoon, you don't refrigerate, it tastes better," said Zabar. "We pick everything ripe and ready to eat. All our products here are organic."

Depending on the hour of the time of day, Zabar says with a smile, "the green houses smell of bread, brownie or croissant."

About half of the items Zabar sells in his deli comes from rooftop farms.

From Manhattan to Brooklyn, whether on rooftops, backyards or in any of the city's 600 community gardens, urban farming is a growing phenomenon.

The movement is helped along by Mayor Michael Bloomberg, who seeks to turn the city into a sustainable development champion. Through "PlaNYC 2030," a program he launched on Earth Day 2007, people who install "green roofs" can get a tax break.

At Randall's Island, in New York's East River, the city's Parks and Recreation Department is currently testing 16 different types of vegetation that could be placed on the roofs of schools, hospitals or other public buildings.

"These are patches of succulent vegetation, like sedum, which protect the roofs, (and) isolate the buildings from the heat because the UV (ultra-violet) sun is not hitting," said senior project manager John Robilotti.

The rooftop vegetation also helps maintain a steady temperature inside and captures storm water, which would otherwise run off into the street.

"The water that does come out is filtered and kept in tanks, and we use it to water when there is no rain," Robilotti said.

The roofs "absorb carbon and create oxygen, so we take carbon from the carbon cycle.

"And they attract birds, butterflies, bees. We even saw a red-tailed hawk," he said.