Green Roofs

I visited the green roof at the California Academy of Sciences in Golden Gate Park in January and was pleasantly surprised! Surprised to see that medium to contain the plants on the steep slopes of the roof are coconut husk trays and surprised to see a wide variety of plant species native to the San Francisco Bay region. Rana Creek Living Architecture, the consultant and installation contractor for the living roof did a fantastic job collaborating with the architect Renzo Piano and the challenges of the roof to come up with a planting medium a plant pallet that supports the native biodiversity of the region. While I am all for green roofs, I get discouraged and frustrated by many of the products being marketed and plant material being used in the name of being ‘green’. Instant green roofs consisting of plastic trays filled with 3” of soil and planted with three varieties of non-native sedum – come on! Is that truly being sustainable? If we are going to create living roofs, let’s do it right! I know cost is an issue, it always will be; but what about the costs of losing biodiversity, or the costs of manufacturing more and more plastic, or the costs of not providing enough soil to at least begin to resemble a sufficient soil profile for soil microorganisms (and ground dwelling insects) to start colonizing and supporting native plants. Let’s push to make green roofs truly ‘green’ and truly ‘living’!! What do you think?

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