Gardening: not just for the front yard anymore

I want to start a new garden. No, I am not talking about a new flower patch in the yard. I am talking about my roof.

Green roofs - roofs covered with vegetation instead of asphalt shingles - are everywhere these days another green trend that has taken hold in urban areas and could be featured in a suburban outpost near you. Granted, green roofs in the ‘burbs are a little far off. They make more sense in the concrete jungle, where roofs already often have a hotel pool or a sunbathing deck installed. Why not some flowers too?

Another reason they make sense in the city: Cities get steamier in the summer. A field of green not only looks more refreshing to the eye, but it cools off a surface that would usually absorb and radiate heat. The interior of the building often stays cooler too, by about 8 degrees.

Green roofs got a boost in the late 1990’s when a particularly sweltering Chicago summer claimed over 700 lives in the city. Mayor Daley declared “heat islands” in the cities caused the heat wave to be more severe than it had to be. One way the heat islands could be cooled off was with green roofs, he said. Soon after, Daley announced the city hall would be the site of a large green roof. Since then, they have grown in popularity.

How do the plants get up there?

In the U.S., green roofs are much more likely to be on a commercial building (think hi rise), however green roofs are available for a single family home. A little Internet research showed a variety of methods, most coming over from Europe, where residential green roofs are more common.

While in my head a green roof installation is a lot like laying sod on top of my asphalt shingles, it is more complex. First of all, my sod roof would slip right off in the first rain. One company has overcome that with a series of trays that lead down to a succession of moisture barriers that wick excess water away to gutters leaving plants watered but not inundated. They look a bit like nursery pots.  

Toyota has developed Roofing Squares that look like very high-tech sod. The squares feature plants on top, a moisture-wicking layer and even a little tread on the bottom. These squares are made to snap together. At $43 a pop they don’t come cheap but they are pretty cool.

But what about my roof?

Sadly, I finally realized that a green roof is a bit heavy for my 1980’s rancher to handle. But leaps forward in the creation of high-tech green roofs and with science backing up the cooling effects on your home and utility bill, I think it’s only a matter of time before my roof is blooming. Maybe if I am lucky, I can put goats up there too.