New York-based greenhouse firm BrightFarms Inc. added a third retailer to its roster.

The Great Atlantic and Pacific Tea Co. Inc., Montvale, N.J., entered a long-term agreement to purchase produce from a BrightFarms rooftop farm in Brooklyn.

A groundbreaking is scheduled in September for a multi-acre greenhouse on 100,000 square feet of rooftop space, with the opening of the greenhouse scheduled for the first quarter of 2013. This is expected to be the largest rooftop farm, growing up to one million pounds of produce per year, according to a BrightFarms news release. BrightFarms plans to supply lettuce, tomatoes and herbs to A&P’s New York metropolitan banners, The Food Emporium, Pathmark and Walbaum’s from the greenhouse.

“Partnering with BrightFarms is a phenomenal opportunity to provide our customers with the freshest, local and most sustainable produce in the supermarket aisle,” said Sam Martin, president and chief executive officer of A&P, in a news release.