MONTREAL -- Montreal company Lufa Farms is building a new commercial rooftop greenhouse that it says will be the biggest rooftop farm in the world.

According to the agricultural company, its fourth greenhouse, which will be in Montreal’s Saint-Laurent borough, will measure 15,200 square metres -- the size of almost three football fields.

"This rooftop greenhouse will double our growing capacity and allow us to feed two per cent of Montreal with fresh, local vegetables," said Mohamed Hage, co-founder and CEO.

“It's an unbelievable step forward for hyper-local, sustainable urban farming.”

The greenhouse will repurpose an existing industrial roof.

"With each greenhouse, we hold ourselves to an ever-higher standard for sustainable design,” said Lauren Rathmell, co-founder and greenhouse director.

“Our new farm will be the most energy-efficient to date and integrate all our learnings from the last 10 years to responsibly grow more vegetables."

Saint-Laurent Mayor Alan DeSousa says he welcomes the initiative as a way to facilitate residents’ access to local, sustainably grown produce while promoting healthy living.

“It will make it possible to fight against heat islands in our district, where more than 70 per cent of the surface area is devoted to industrial and commercial activities,” he said.

Representatives with Lufa Farms say construction began last September and is expected to finish by March 2020.

Lufa Farms was founded in 2009.