Companies spend millions of dollars on creating rooftop farms to demonstrate how "green" they are. There is no doubt advertising with living green is a good idea because it makes the customers believe that the company practices environmental leadership.
However, the reality looks very differently.
Recently a food company started a huge campaign promoting their rooftop farm (and their green leadership) by opening a 17,000 square foot rooftop farm on the East Coast. They were optimistic that they could grow 10,000 pounds of produce during the short growing season. This is approximately 25% over the average vegetable and berry crop yields estimated for New England on the ground during a good year, based on traditional irrigated farmland.
Since environmental conditions on rooftops are more extreme, achieving this goal seems ambitious and will require higher amounts of water and fertilizer. With more moisture in green roof soil the main benefit of green roofs (stormwater retention) is sacrificed and the run-off will most likely now contain more nutrients than in the run-off from traditional farms. Nutrients are already the number one pollutant in our waterways...
Click here to read the rest of the article on the Green Roof Technology website.