Method is a company committed to making environmentally safe personal hygiene and cleaning products that come in bio-degradable bottles and distributed by a fleet of trucks that burn bio-diesel fuel. And soon, it will have a factory with the largest rooftop greenhouse in the world.
When it decided to build a new $20,000,000 factory on Chicago’s South Side, it made sure it was powered by three solar “trees” that move with the sun and a 230-foot-tall wind turbine. Combined, the on-site renewable energy sources generate a third of all energy for the building, according to Inhabitat.
But the most innovative element of the factory is on the roof, where a a 75,000 square foot greenhouse is set to be fully planted this fall. That’s a large as a full city block and larger than a football field. When complete, it will grow up to one million pounds of pesticide-free greens, including kale, arugula, bok choy, and butterhead lettuce a year.
Method looked for inspiration to Ecover, its green cleaning partner brand.  In 1992, Ecover built its first “ecological factory” using sustainable building materials and featuring a green roof. “We wanted to meet the highest standards of green building,” says Saskia Van Gendt, Method’s Chief Greenskeeper.
The rooftop greenhouse is much more efficient than a conventional agriculture operation, using 20 times less land and 10 times less water. Instead of being planted in the ground, the plants are grown with a hydroponic system that requires water but no soil. Computer systems control irrigation, heating, cooling, and other variables.
It also weighs a lot more than a traditional roof — about 1,000,000 pounds — which meant the roof needed additional structural support. Once fully planted this fall, it will help insulate the factory below, reducing heating and cooling costs.
“We need to use our urban spaces more efficiently,” says Van Gendt. “Rooftop greenhouses are a representation of a model of doing that.”
