Finding Space in an Unlikely Place: Minnesota's First Rooftop Farm

These people don't look like farmers, I thought as I met some of the staff of The Cornerstone Group, a local real estate development company that manages both retail and domestic properties. Colleen Carey, Cornerstone's president, was dressed in gauzy white, while her colleagues wore suit jackets.

“We had a presentation this morning,” Colleen explained. “We don't normally dress like this.”

She quickly proved she and her staff were unfussy and practical. As they guided me along the building, Colleen picked up stray bits of trash and leaves as she went. We entered a utility room with a dauntingly steep metal staircase to the roof of Kensington Park building. Topside, we looked over Richfield's business district. The view wasn't great, but I hadn't come for that. What I wanted to see was the Cornerstone Rooftop Farm, the first of its kind in Minnesota.

Rooftop gardens are fairly common, Ben Hertz clarified, just as I was about to ask. He does development and communication for The Cornerstone Group. But those are for individual use. Cornerstone's project is a farm. Even though small in scale, the projected produce is intended for many people, not just a few. They've embarked on an experiment to maximize available space in cities while growing small, environmentally sound crops in the city. This coming season, produce from Cornerstone Rooftop Farms will be served at Lucia's Wine Bar and Lucia's to Go, both owned by chef Lucia Watson, an early champion of farm-to-table dining.

The idea for the farm rose out of the recent downturn in the economy. As construction of new buildings stalled, Colleen and her team wondered how they could transform existing structures, going beyond bricks and mortar to create more interesting spaces for people to work, live and shop. A rooftop farm would give a practical use to existing space, plus increase access to fresh whole foods for city dwellers.

To create the farm, the Cornerstone Group partnered with Ecological Gardens, a locally owned permaculture landscape design company. Permaculture, a shortening of permanent agriculture, is an attempt to create human landscapes that rely less on industrial sources and thus promote natural ecosystems. Ecological Gardens designed the Cornerstone Rooftop Farm, and will be working it to grow and harvest fruits and vegetables.

They started with lightweight, square modules with raised beds. Raised beds are more expensive than simply putting soil on a rooftop membrane, but are more practical. They are movable and can be expanded on this roof up to four times, depending on the success of the crops. The beds are framed by hoop structures, which can extend the growing season, and protect crops from severe weather. Only minor retrofitting of the existing roof was needed to support the new structures. Beth Pfeifer, a senior project manager who trained and worked as an architect, said that future construction could easily build in rooftop farm needs from the start.

Within the modules are two different planters. Sip containers are a two-bucket system; water works up from the bottom by capillary action. Fifteen varieties of heirloom tomatoes twelve varieties of peppers are planned for the sip containers.

The second planter is an earth box, a shallow tray with dirt and a perforated membrane on the bottom that allows the water to stay at a lower level. This results in less evaporation from the sun, and reduces the water needed to cultivate the crops. Carrots, radishes and chives will be grown in the earth boxes.

The sip planters and earth boxes are the first phase; a future possibility is the metal slatted standing wall to support vertical plants in a later phase of the project. Other phases might include agriculture in small spaces on and around Cornerstone properties. Imagine a retail center or a housing group with columnar apple trees or small patches of berries!

Rooftop farms, new to Minnesota, are a growing phenomenon. Across the U.S., several restaurants have them. Bon Appetit's April 2010 issue named 10 restaurants as best in roof-to-table dining, and  two from Chicago were featured in Cafe Magazine. Eagle Street, a rooftop farm in Brooklyn, appeared recently in The Atlantic, and with four other New York rooftop farms at The City Greens. And in March, Fast Company magazine named Mike Yohay of San Francisco's Cityscape Farms one of the 10 most inspiring people in sustainable food.

The rooftop farm is only one local-food experiment Cornerstone is working on. They are also partnering with Backyard Harvest, a community-building urban permaculture program that grows food in the yards of homes, schools and businesses. Together, they've installed a garden for residents of Rivertown Commons, a residential property in the Frogtown neighborhood of St. Paul. The program launched on Earth Day this year with food education and demonstrations. Urban farmers from Backyard Harvest will be working the garden; the produce will be available to residents in a CSA-based distribution system. Children who live there can plant salsa gardens in wine barrels. If the Rivertown Commons project is a success, Cornerstone hopes to roll it out to other properties.

I'll have my fingers crossed for the success of the rooftop farm and the Rivertown Commons garden. The plans, projects and plants all seem to be doing well so far. I'll check back in a few months to see -- and hopefully taste -- the results.

Kristin J. Boldon lives in Northeast Minneapolis with her husband and two sons. She grew up in Central Ohio, but moved to Minnesota in 1998 from the east coast. (We're glad she stayed!) Kristin has a B.S. in Business from Georgetown University and an M.A. in Religion from Temple. In her so-called spare time, she cooks, bakes, practices yoga, reads, and writes for the Eastside Food Cooperative's newsletter on health and wellness, and for her own blog Girl Detective. Her last post for Simple Good and Tasty was The Revolution was Televised: Looking Back at Jamie Oliver's Food Revolution.