Production and Financial Analyses of the Rotating Living Wall, an Urban Agricultural System

Abstract

Experiments were performed from June 2014 to May 2015 at Penn State University’s greenhouse facilities in order to understand the production capacities and financial viability of an innovative growing system referred to as the Rotating Living Wall produced by GreenTowers, a student innovation/entrepreneurship team. The system is a six-foot vertical conveyor that rotates troughs of microgreen plants to achieve even distribution of sunlight as well as relatively low maintenance within a minimal square foot area. Experiments were performed to understand differences in seasonal yields, differences in yields based on variety of microgreen, yield comparison to a traditionally grown microgreen control group; both on a yields per/trough method as well as a yields per/ft.2 method, rotational timing, moving versus stationary growth, differences in growth based on media depth, and differences in production yields from supplemental lighting. Performance criteria were based on measuring fresh weight, dry weight, height, and SPAD-meter readings (soil plant analysis development). Differences in yields throughout seasons were significant as well as differences between the Rotating Living Wall systems compared to a control group of traditional static greenhouse benches. The use of LED supplemental lighting provided significant differences in yields throughout winter season growing. Rotational timing, media depth, and physical movement of plants showed minimal or no significant influence on yields. By establishing the potential revenues and costs that were part of growing with the Rotating Living Wall system, financial viability was analyzed showing that these systems could be profitable when utilized in State College, PA, within certain operating parameters. The research completed throughout these studies has not only provided a baseline of operation for the systems but has also shown potential for the development of urban agricultural systems capable of aiding in the elimination of “food deserts” or urban neighborhoods and rural towns with limited food access.