As more people join in the challenge to feed the world’s growing population, a not so new concept – roof gardens – may be a part of the path forward.
A roof garden is any garden on the roof of a building or structure. They have been used by humans since ancient times. In Part 1 of this series, Feeding 9.6 Billion People: Will Vertical Farming Take Roots?, the post indicates that the concept of vertical farming appears to have been around since the Hanging Gardens of Babylon. And while it is debated by some if the Hanging Gardens actually existed, the visualized concept is less of a garden and more of a simulated mountain with rooftop gardens and/or multi-level terraces.
Roof gardens were grown in the Villa of the Mysteries in ancient Pompeii. The medieval Egyptian City of Fustat had a number of high-rise buildings in the early 11th century that were described as rising up to 14 stories, with roof gardens on the top story complete with ox-drawn water wheels for irrigation. [Ref 1] Fast forward to today, and roof gardens appear to be making a comeback with growing appeal and usage in the U.S. and other countries.
Roof gardens can be as simple as a few containers (micro-gardening), to a small green house, to a more expansive climate-controlled structure. There are a number of advantages to a roof top garden, regardless to whether it is on top of the first floor or the 15th floor. For starters, they provide open space in urban areas by utilizing available unused or underused space. When one considers the challenge of finding available farmable land in or near cities and urban areas, and when the cost of this lands is at a premium, roof top gardens or farming becomes even more appealing to urban farmers.
Another plus includes the addition of a more eye-appealing landscape to what may have been an eyesore. Involving an architect or contractor is definitely suggested for an extensive design. You’ll want to know if the building or roof is safe to support the additional weight. You’ll also need to determine how to get water to the rooftop.
Another notable attribute of roof gardens and rooftop farming is the ability of plants to reduce heat absorption. If the building absorbs less heat, less energy will be required to cool it. Studies [Ref 1] also show that roof top gardens can reduce the urban heat island effect and reduce air pollution.
One of the largest roof farms is located in the City of Chicago. [Ref 2] It is located at the top of McCormick Place, the largest convention center in the U.S. and North America. One of the goals in developing the roof farm is to supply produce for the center’s food service vendor. Roof farms can grow a variety of vegetables and utilize several cultivating methods including green roof, hydroponics, aeroponics and container gardens.
The folks at McCormick Place hope to expand their farm to other sections of the roof to eventually have three (3) acres under cultivation. While the roof gardens have a number of benefits, there are a number of costs and risks. There’s the increased liability and risk of having more persons access the roof, and necessary caution is needed to maintain the rooftop’s materials and membranes. Permitting can also prove to be challenging along with dealing with natural conditions of sunlight, wind, snow, and rain.
Although I am not one to make New Year resolutions, I predict that urban farming will grow in 2015.
1. Wikipedia, www.wikipedia.org
2. Rooftop Farming Is Getting Off The Ground, Eliza Barclay, National Public Radio (NPR), September 25, 2013, http://www.npr.org/blogs/thesalt/2013/09/24/225745012/why-aren-t-there-more-rooftop-farms, Last viewed on 12.28.2014