Plant Growth and Water Use in Plastic, Fiber, Keratin, and Root Pouch Containers

This one-factor completely randomized experiment was conducted in Michigan, Kentucky, Mississippi, and Texas, in order to test plant growth and water use in containers made from material other than virgin plastic. From July 2011 to June 2012, Euonymus fortunei ‘Roemertwo’ were planted in three types of #1 (~3.8 L) containers (treatments) and evaluated. Container treatments were: 1) polyethylene PF400-SM (control); 2) Western Pulp 7X7RD (WP); and 3) Kord 07.50 Fiber Pot (Kord). From June 2012 to May 2013, Buxus x ‘Green Velvet’ were evaluated in four types of #1 containers: 1) control; 2) WP; 3) root pouch 15–20 month (RP) 4) keratin pot (KP). Substrate volumetric moisture content (SVMC) was determined by EC-5 moisture sensors in 2011, GS3 and EC-5 sensors in 2012 (Decagon Devices, Inc., Pullman, WA). Plant daily water use (DWU) was calculated as SVMC 5 minutes after irrigation minus SVMC immediately before the following irrigation period multiplied by container volume. Plants were irrigated to replace 100% DWU. For E. fortunei, in all states, plant growth and biomass were not different between treatments. A higher mortality rate in plastic than Kord and WP container was observed at the end of 2011 growing season. The DWU for WP and Kord varied by states in both years. The root zone temperature of KP was similar to control, and for WP and RP was 9% and 15% lower than control in Michigan, container temperature in other states varied. Mortality of Buxus was 0% for all states by October 2012; mortality will be evaluated in May 2013.