April 23, 2014

The Mercer Garage roof becomes an award-winning public garden

Photo by Eric Higbee [enlarge]

UpGarden transformed the roof with shared spaces, a communal garden and whimsical elements like an Airstream trailer that serves as a tool shed.

The garden on top of a three-story garage near Seattle Center won this year's top award from the Washington Chapter of the American Society of Landscape Architects.

The P-Patch is called UpGarden and it has views of the Space Needle, Queen Anne and parts of downtown. It was designed by Kistler|Higbee Cahoot.

The team also included structural engineer Bykonen Carter Quinn and Seattle Urban Farm Co., a design/build consultant for rooftop vegetable gardens.

The 30,000-square-foot garden is on Mercer Garage at 300 Mercer St. City officials say it is the first publicly accessible, large-scale community rooftop garden in the U.S.

Jurors called it an outstanding example of turning underused urban infrastructure into vibrant community landscapes.

They said using common, simple construction materials and volunteer labor helps build an ethic of eating locally and environmental stewardship.

The shared lawn and picnic table, small seating areas and a communal Giving Garden emphasize the social aspects of the garden, they said.

The space also has whimsical elements, with an Airstream trailer that serves as a tool shed and a Ford Galaxie fashioned into a planter.

“They took an underused structure and gave it new life,” said juror Marsha Lea in an interview this week.

Lea, of Washington, D.C.-based Lea Landscape Architecture, said she liked that the car and trailer now are “focused on gardening as opposed to denigrating our environment. It was just such a nice idea.”

Lea said similar gardens could be created on unused garage roofs in other communities. It is a “relatively inexpensive way to make something productive,” she said.

Another juror, Keith LeBlanc of Boston-based Keith LeBlanc Landscape Architecture, said it was “exemplary” that the landscape architect and engineer could pull off the challenge of designing a community garden for a garage roof.

“So many community gardens look like the junk farm because (they are) not well organized,” he said, but that's not the case here.

LeBlanc also was impressed that the UpGarden design was so good it could be built successfully with volunteer labor.

He mentioned nice touches such as installing planters of different heights to accommodate the slope of the roof, and adding the Airstream and car to the garden.

“It looked like a delightful place to be,” he said.

Seattle Center and Seattle Department of Neighborhoods were the clients for the project, which opened in the summer of 2012.

Clearance in the garage wasn't high enough for dump trucks, so soil was trucked to the site and blown onto the roof with hoses.

The roof can hold 40 pounds per square foot, but wet soil can weigh 100 pounds per square foot or more. So soil was put in raised wooden terraces separated by wide paths to keep the weight below the structural limits.

The 1960s Airstream trailer, which was found cheap on Craigslist, was lifted by crane onto the roof.

The garden has about 100 plots, communal space, and room for ornamental and pollinator plantings.

The budget was $150,000, with funding from the 2008 Parks and Green Spaces Levy.

Much of the publicly owned space on Lower Queen Anne has buildings or parking lots on it, so the city proposed UpGarden.

Mercer Garage covers almost two city blocks, and is seldom used to capacity. Seattle Center's redevelopment plan calls for the garage to eventually be torn down.

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