Should We Start Gardening on Our Roofs? Science Says That's Not Completely Insane
When you tell someone that you have a personal garden, they will likely imagine some raised garden beds in your backyard, a grow tent in your closet, or maybe just a couple of pots in a windowsill. But, if you tell them that your garden is actually on your roof, most people would probably respond with a puzzled look. However, the latest science says that we should indeed grow gardens on our rooftops to combat climate change.
Growing a garden on the roof is called cultivating a “green roof” or just a “rooftop garden.” These rooftop gardens provide many benefits to the environment and homeowners alike. For starters, they provide shade. Vegetation covering the surface of the roof prevents sunlight from reaching the actual house. Plants reflect sunlight as well as absorb it as part of their photosynthetic process, reducing the amount of solar radiation heating the roof.
Plants also evapotranspirate, releasing excess moisture back into the atmosphere, which has a cooling effect. In addition, garden roofs can help reduce a home’s energy consumption through insulation, cooling the house during the summer months and warming it in the winter.
Green roofs also contribute many benefits to the local environment. They can improve air quality through oxygen production, as well as reduce greenhouse gas emissions by carbon capture. Garden roofs can also filter pollutants out of rainfall water and are a great solution for stormwater runoff.
But that’s not all. Rooftop gardens remove heat from the atmosphere. Plants shade the surrounding environment thanks to their height and density, and also reduce the “heat-island effect.” The heat island effect is caused by human activities in urban environments, which produce higher temperatures than in outlying areas. It typically results from the absorption of heat into roof structures. But thanks to the insulation of rooftop gardens, heat is reflected and absorbed.
The combination of garden plants can also create a microclimate. A microclimate is a very small area differing in climate from the immediate surrounding area. This occurs thanks to the interaction of the differing plants with the humidity as well as the other atmospheric conditions.
The U.S. Environmental Protection Agency reports that green roof temperatures “can be 30–40°F lower than those of conventional roofs and can reduce city-wide ambient temperatures by up to 5°F.”
By adopting this odd practice, you can promote sustainability and contribute to a better local environment for everyone. So, be the weird neighbor — start gardening on your roof.