ARS | Publication request: Determining the suitability of alternative greenhouse/nursery substrates

Submitted to: Annual Horticulture Field Day Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: September 30, 2011
Publication Date: October 6, 2011
Citation: Witcher, A.L., Blythe, E., Fain, G.B., Curry, K.J., Pounders Jr, C.T. 2011. Determining the suitability of alternative greenhouse/nursery substrates. Annual Horticulture Field Day Proceedings. 38:23.

Technical Abstract: Greenhouse and nursery crop producers have greater awareness and access to materials not traditionally used as container substrates. Materials such as composted plant debris and animal wastes, industrial by-products, and wood biomass have been successfully used for crop propagation and production. Reduced plant growth in wood-based substrates has been attributed to a variety of factors, including phytotoxity. The objective of our research was to develop a method for identifying phytotoxicity in processed whole pine trees, while examining the potential of such methods for testing other alternative substrates. A seedling growth test was conducted to evaluate root growth of three plant species (lettuce, oat, and tomato) in four substrates [aged (WPTA) and fresh (WPTF) whole pine tree, pine bark (PB), and a peat-lite mix (PL)]. Total root length was significantly greater for PL within each species, while aging the whole pine tree material did not result in significantly greater root length. Substrate air space had a greater effect on root length compared with the substrate chemical properties. Further investigation of substrate physical properties is required to determine which factors contribute to reduced root development.