Investigating Growth Media Effects on Rooftop Vegetable Production

Green roofs, including rooftop gardens, are growing in popularity because they provide many benefits to a community. They are known to improve air quality by reducing carbon dioxide levels and raising oxygen levels in the atmosphere. They increase biodiversity, reduce storm water runoff, and provide thermal benefits. Recently, they have been used to provide fresh, nutritious produce. In our project, we will evaluate rooftop vegetable production and provide the vegetables to SIUE students, staff, faculty, and guests. SIUE Head Chef Eric Ruhmann is fully supportive of the establishment of our rooftop vegetable garden and will use the produce in the university dining facility. Extra will be donated to initiatives such as SIUE's Campus Kitchen, which keeps food from going to waste while feeding those in need. Our project will also increase knowledge of alternative green roof applications by demonstrating a new method of food production in the urban environment using a waste product – drinking water treatment solids. A rooftop plot outside of the university restaurant with a total area of about 600 sq. ft. will be divided into four equal quadrants, each approximately 150 sq. ft. of growing space. Gardensoxx, 8 in. in diameter by 3 ft long, will be placed in 9-ft. rows, with a 16 in. walkway between each row. Each of the four quadrants will contain a total of 12 Gardensoxx (for 48 total). Each individual 3-ft. Gardensoxx section will contain one of three different growth media (100% compost; 50% drinking water treatment solids and 50% compost; 100% drinking water treatment solids). Each rooftop quadrant will contain one vegetable variety - lettuce, carrots, cucumbers, or pole beans. Upright fencing will be used to support vertical growth of the cucumbers and pole beans. After the vegetables have fully developed, yield will be harvested and total plot yield and vegetable quality will be determined from each growth media blend. Data will be analyzed to determine the impact of the media composition on vegetable yield. Our replicated experimental design will enable us to determine which growth media blend produces the most and highest quality vegetables in the rooftop garden.