Advice on Creating a Rooftop Garden

[Shirleypal]

August 19, 2009

The ecological benefits of gardening on your roof

Dear EarthTalk: I’m sure there are many good environmental reasons to build a rooftop garden. Can you enlighten? And also I’d like to know how to go about creating one and whether or not some municipalities might offer incentives to do so.
-- Linda, via e-mail

Indeed there are many good reasons to build a rooftop garden, or a so-called “green roof”—whereby layers of soil and plants on top of homes and buildings provide a host of environmental “services” for the living space below as well as for the surrounding ecosystem. Unlike traditional roofs, green roofs thrive on (and filter) precipitation, decreasing the amount of pollution-laden stormwater run-off draining into our waterways. And thanks to the process of photosynthesis, the plantings create oxygen, cleanse the air and absorb carbon dioxide before it gets into the atmosphere and adds to our global warming woes.

Green roofs also provide insulation: All those layers of organic material help keep a structure warm in the winter and cool in the summer, and help cut energy use and costs. Migrating birds and other wildlife have been known to take a shine to green roofs, especially in urban areas where natural habitat options are limited. Likewise, homeowners and building residents tend to view their green roofs as oases of peace and tranquility within otherwise noisy and concrete-laden urban environments
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Green roofs are gaining in popularity. North Americans added some 3.1 million square feet of them to their buildings in 2008 alone - up 35 percent from 2007. Pictured: a rooftop garden in the Pine Market section of Seattle.