Potential for Agriculture in Combination with Native Plants on Extensive Green Roofs

Abstract

As human populations continue to increase and degrade the environment, efficient and environmentally conscious utilization of space is becoming more imperative. With their myriad of benefits to humans and the environment, green roofs have the potential to alleviate this issue. Research was conducted to analyze the potential for agriculture in combination with native plants, on extensive green roofs, in an attempt to determine which of these benefits can be combined. Six green roof simulation boxes, three of which were 10.16cm in depth and three of which were 15.24cm, as well as three ground plots were constructed to compare four perennial native species and four perennial food crops grown both alone (food crops only or native plants only) and in mixture. Change in diameter (radial spread), change in height, above ground biomass, water content, and fruit count were analyzed after one growing season to determine growth trends for a green roof system. Results indicated that there is potential for agriculture on extensive green roofs. Food crops grew more (change in diameter, change in height, and dry weight) in mixture with native plants than alone, both food crops and native plants grew more (change in diameter, change in height, and dry weight) in deeper plots than in shallow boxes or the ground, food crops had a higher water content in shallow plots than deep plots, and more strawberry fruits were produced in deep plots. This research indicates that extensive green roofs, planted with food crops and native species, are a viable option to consider for reducing environmental degradation and adding to humans’ quality of life.