Rooftop food gardening is a production system in urban agriculture based on green roof technology. In order to broaden the scope of this practice, the use of relatively shallow media depths must be explored since deep media makes roofs heavier than can be supported by most existing urban flat roofs. In this study the authors compared vegetables grown on a roof and on green roof platforms in 10 cm of media and in the ground over three growing seasons to determine the practicality of using an extensive green roof system in food production. Crop yield, crop quality, and plant aboveground biomass of tomatoes, green beans, cucumbers, peppers, chives and basil measured and used to compare the three growing locations.
Results/Conclusions
All of these plant species were able to survive and produce biomass on the green roof, on green roof platforms and at ground level. Overall, yields were higher in the ground in 2009 when the plots were irrigated, and there were similarities in yields between green roof and green roof platforms. Aboveground biomass showed similar trends. Chives were the exception with no difference in yield between locations after the first year. Variability in the total yields and end of the season biomass of the vegetable plants may, in part be due to yearly variation in weather conditions. The results suggest that with proper management, vegetable and herb production in an extensive green roof system not only possible, but productive