Landscape architects and designers advocate for more rooftop gardens in city

A loosely knit group of local architects, designers and planners has been busy touting one of Sacramento’s least talked about assets – its rooftops.

The Rooftop Alliance advocates for the development of urban rooftop gardens be they of the vegetable or flower variety, or just a communal public space.

In Sacramento, there are only about a dozen rooftop gardens, said Tristan Osborn, member of the Rooftop Alliance and founder of Cobblestone Placemaking.

To boost that number, the alliance is offering its second annual UPark event – a two-day pop-up event at a parking lot at 20th and L streets that ends Sunday. Offerings includes a local beer garden, a bike-in movie theater, as well as performances by the Sacramento Ballet.

“We wanted to give residents an idea of what we can experience if we look up and start activating our rooftop spaces,” Osborn said.

The Alliance hopes the event helps build “a market for this kind of thing” and makes it feasible, said Bernadette Austin, member of the Alliance. “Right now, we’re throwing parties and talking about that market – to get people interested in the idea.”

Sacramento is a latecomer to the rooftop garden party. The idea is as ancient as the Hanging Gardens of Babylon. Today, cities including Toronto and Chicago have a decades-long history with rooftop gardens as well as a robust inventory of them.

With the ascent of the farm-to-fork movement, many in urban areas are looking for more places where food can be grown and see rooftops as an option. Part of the attraction is the dwindling number of affordable or undeveloped plots of land in city cores.

City Councilman Steve Hansen is among those locally interested in seeing more such gardens dot Sacramento’s rooftops.

“The opportunity to make urban gardens or rooftop gardens here is a remarkable one because of our climate,” Hansen said.

Hansen said he has sponsored a measure to be heard before the council this month that, if approved, would allow private property owners to turn their parcels into urban farms and offer a property tax break through an agreement with the city and the county.

“It’s sort of a quasi-conservation easement,” Hansen said. “And it’s a no-brainer.”

Hansen said allowing residents to create such gardens harkens back to World War I and II, when citizens were encouraged to start “Victory Gardens.”

Also called “War Gardens” or “Food Gardens for Defense,” people in the U.S. and Great Britain grew their own food that they planted on private and public spaces including playgrounds, churches and city parks. The goal was to reduce the pressure on the public food supply during wartime.

Though installing a green roof can cost two to three times that of a new roof, a rooftop garden can make a roof last three times longer than normal, said landscape architect Ed Chandler, also with the Alliance.

“The trade-off is you get, in addition to energy and stormwater benefits, a green roof where you protect a roof for 50 years instead of 10 years,” Chandler said.

In essence, he said, a roof garden acts as a layer of insulation. Unlike a typical shingle roof where the sun’s energy streams down and gets passed on to the layer under the roof, plants in a rooftop garden absorb the energy and convert it into sugars.

“What you’re doing is really reducing the temperature cycle,” Chandler said.

For Osborn, the ideal rooftop garden in Sacramento would not only grow fruits and vegetables but would also be a place where people could congregate over a grill. It also would allow users to experience the city in a different way, she said.

“In Sacramento, since it is so flat here, most people experience the city almost entirely on a street-level basis,” Osborn said. “From a designer’s point of view, a big appeal of the garden would be being able to walk out on a rooftop and really see the city.”