This past spring, I wrote about the knockout William McDonough-designed flagship production facility currently being built in Chicago by Method, slavishly adored purveyor of advanced air fresheners, sheet-less dryer sheets and sweet-smelling hand soap sold in plastic sea trash bottles.

Method’s 150,000-square-foot production/bottling/distribution complex aims to really raise the bar for sustainable manufacturing facilities with on-site wind turbines (this is Chicago, after all), ground-mounted solar panels and a commendable goal to become the first ever LEED Platinum certified production plant in the packaged goods industry. Due to open early next year in Pullman, a historic manufacturing hub and residential district on Chicago’s South Side, the local job-creating facility will be the first domestic production plant for the San Francisco-headquartered cleaning product powerhouse and it's European owner/sister company, Ecover.

Back in March, details were scant about the $30 million facility’s most remarkable — and surprising — feature: a massive, community-benefiting rooftop greenhouse dedicated to urban agriculture. Yesterday, additional details emerged about the soap factory-topping farm and they’re quite impressive.

Ringing in at 75,000-square-feet, the state-of-the-art rooftop greenhouse will be the largest of its kind in the world, capable of producing a staggering 1 million pounds of super-fresh, pesticide-free herbs, veggies and leafy greens each year. Said produce will be distributed to Chicagoland restaurants and farmers markets along with community groups within Pullman and the rest of the South Side.

The somewhat unlikely marriage of green cleaning product manufacturing and urban agriculture — it's all very Cradle to Cradle meets farm to table — will be overseen by Method in partnership with Gotham Greens, a venerable Brooklyn-based rooftop farming firm that has been cultivating ultra-fresh produce — bok choy, Swiss chard, basil, arugula and more — on disused rooftops across New York since 2011.

The Pullman project will be the first rooftop hydroponic farm outside of the five boroughs for Gotham Greens. The company’s most highly visible (but not the largest) New York project to date is the rooftop mini-farm at a Whole Foods retail outpost in Brooklyn’s Gowanus section.

Says Viraj Puri, co-founder and CEO of Gotham Greens, in a joint press release issued by Gotham Greens and Method:

Chicago has shown remarkable leadership in urban farming and green building over the past decade and we’re thrilled to be contributing to the trailblazing work being done in these sectors and furthering Chicago’s position as one of the greenest and most innovative cities in America. We’re particularly honored to be partnering with Method and the Pullman Park development and community. We are dedicated to providing our customers and local residents with the freshest and best tasting, hyper-local produce available, 365 days of the year.

Gotham Green’s innovative hydroponic growing methods use 20 times less land and 10 times less water than conventional agricultural operations, all without the need for pesticides and other polluting agricultural chemicals. And those nibbling on Gotham Greens-harvested produce needn't worry about it being tainted with E. Coli, salmonella and other foodborne pathogens as Gotham Green's enclosed, climate-controlled growing facilities are sterile.

The Gotham Greens-operated rooftop greenhouse atop Method's new dual-use facility is expected to be fully operational by the spring of next year.

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Matt Hickman ( @mattyhick ) writes about design, architecture and the intersection between the natural world and the built environment.