West Philadelphia pilot garden

Elderly residents sit on their front stoops watching tattooed hipsters peddle by on fixed-gear bikes.  This cultural juxtaposition runs rampant throughout West Philadelphia’s Cedar Park neighborhood, while grit and urban decay provide a strange sense of continuity form one block to the next.

One row house is different from the rest, although you would never guess it when looking from the street.  This two-story building is home to a rooftop gardening pilot project, built by a local group called the Philadelphia Rooftop Farm (PRooF).  PRooF volunteers gathered on the roof this past Sunday to bring a spark of green to the neighborhood.

The goal: to build two vegetable planters (out of a series of four), each measuring 3′ x 3′.  The volunteers first inserted corrugated plastic foundation containers into a wood frame, which they had previously built.  Next, they installed a plastic drainage layer, two layers of separation fabric, and planting soil.  One volunteer looked up several soil recipes on her iPhone, and the group decided to vary the mix in each planter in order to see which blend yields the healthiest crops.  After laying the soil, the volunteers covered the planters with black plastic, in order slow desiccation (soil drying) and stifle weed growth.  They slit the plastic and planted a variety of seedlings, including lettuces, chard, cucumbers, eggplant, and herbs.

The planter design was a long time in the making.  Back in 2010, PRooF worked with a team of volunteer design and engineering professionals from the Community Design Collaborative (CDC) to further the group’s rooftop planter vision.  The final CDC design combined base irrigation techniques that are common in Canadian rooftop planting bins, with wood framing construction, which is more typical of raised beds.  The hybrid proved easy to install, and was made, in part, of salvaged materials.

PRooF’s plans for rooftop greening extend beyond this first installation.  The active group intends on evaluating the performance of the West Philadelphia pilot project, and then building more planters around the city.  Home owners are welcome to volunteer their roofs to the group, along with a commitment to water and occasionally tend to the crops.  It is important that each roof is structurally sound enough to bear the weight of the planter, although the CDC design included a strategy for distributing the planter’s weight across a row home’s party walls.

This is an exciting time for rooftop gardening in Philadelphia.  Thanks to organizations like PRooF, we finally have the “proof” that rooftop gardening on Philly row homes is easy!