Turner Smith

Former Graduate Student

Degree: M.S., 2018

Thesis Title: Physical and Chemical Characterization of Various Wood Components in Horticultural Substrates

Wood is NOT wood, is NOT wood, is NOT wood!!! The use of wood-based substrates (or wood components in peat-based substrates has evolving since the 1990’s when products were first developed and commercialized in Europe. It was not until 2004-2005 that research began here in the United States on using these materials as a component in horticultural substrates. Since 2004 there has been a growing interest in the use of wood materials in substrates. At no time has the potential been greater for the inclusion of these materials into our current greenhouse and nursery substrates than now. With interest and opportunity comes the need for understanding the differences in these products/materials and an even greater need for a systematic understanding of how wood components are manufactured and used. Over the past several years many different wood components have been designed, engineered/processed, and evaluated which has led to greatly furthering the potential of these materials in present-day growing media formulations. Research strategies have advanced significantly from the initial strategy/mentality of “find it, grind it, put it in a pot, and see what happens” to very precise product development methodologies that are in practice today. After realizing that fresh (non-composted or aged) wood components were viable as alternative substrate materials, more technical assessments of chemical, physical, and hydrological properties are being conducted on wood materials from Europe and North America. The chemical properties of interest include pH, pH buffering capacity, electrical conductivity, phytotoxicity, carbon: nitrogen ratios, efficacy and/or tie-up of applied PGRs, etc. Physical properties of interest include particle size, particle shape, bulk density, air and water relations, total porosity, compaction potential, shrinkage, nesting potential, blending characteristics with peat and other materials, the flowability of substrates containing wood fiber in potting and transplanting machines, etc. Hydrological properties of interest include initial hydration and water capture, available and unavailable water, re-wettability, infiltration, percolation, and conductivity (especially with different irrigation systems in greenhouse crop production).

Turner Smith