World's largest rooftop greenhouse in Montreal

"A greenhouse atop a Montreal warehouse growing eggplants and tomatoes to meet the demand for locally sourced foods has set a record as the largest in the world . . . It's not an obvious choice of location to cultivate organic vegetables — in the heart of Canada's second-largest city — but Lufa Farms on Wednesday inaugurates the facility that spans 160,000 square feet (15,000 square meters), or about the size of three football fields . . . The company's mission is to grow food where people live and in a sustainable way . . . It is the fourth rooftop greenhouse the company has erected in the city . . . Since then, competitors picked up and ran with the novel idea, including American Gotham Greens, which constructed eight greenhouses on roofs in New York, Chicago and Denver, and French Urban Nature, which is planning one in Paris in 2022. A local Montreal supermarket has also offered since 2017 an assortment of vegetables grown on its roof, which was "greened" in order to cut greenhouse gas emissions linked to climate change . . . At Lufa, about 100 varieties of vegetables and herbs are grown year-round in hydroponic containers lined with coconut coir and fed liquid nutrients, including lettuce, cucumbers, zucchini, bok choy, celery and sprouts . . . Bumblebees pollinate the plants, while wasps and ladybugs keep aphids in check, without the need for pesticides. Enough vegetables are harvested each week to feed 20,000 families."