Largest commercial rooftop greenhouse

Covering an area of 15,217.5 square metres (163,800 square feet), the largest commercial greenhouse built on top of a building is located in Ville Saint-Laurent, Montreal, Quebec, Canada. Operated by Lufa Farms (Canada), the greenhouse, which began construction in September 2019 and opened in August 2020, sits above an old warehouse (formerly a headquarters for department store Sears), which now contains the company's administration and distribution facilities. It captures rain and meltwater for its closed-loop irrigation system and for insulation utilizes two-layered glazed panels and a double set of curtains. It is capable of growing enough food for c. 10,000 families – about 2% of the total population of Montreal.

Lufa Farms was founded by the Lebanese-American husband and wife team Mohamed Hage and Lauren Rathmell in 2009. They are believed to have built the first commercial urban rooftop greenhouse (also in the Montreal region) in 2010; it had an approximate area of 9,500 m2 (102,260 sq ft).

Currently, the primary produce grown in the Ville Saint-Laurent rooftop greenhouse are several varieties of tomato.

In 2023, an indoor farm was added inside the Ville Saint-Laurent Lufa Farms building, using energy-efficient LED lighting and hydroponics to grow a variety of crops including herbs (e.g., basil), salad leaves (e.g., lettuce and spinach) and celery.