Rachel Edwards

Graduate Research Asst

Degree: M.S. student

Thesis: Characterization of Water Fate in Soilless Substrates

There have been many advancements in growing media (substrates) for the production of horticultural crops over the past several decades. The emphasis on new and different growing media components, other than peat moss and perlite, comes from various perspectives including cost, availability, sustainability, and performance. There is a similar phenomenon of new materials and approaches happening within horticulture relative to alternate containers and container systems used for crop production. Growers are rightfully hesitant to adopt new practices without adequate research to understand how new materials and changes in production practices will affect plant production and quality. Specific to advances in growing media, wood substrates have gained popularity in the European and North American markets and have proven to have similar physical properties to that of other traditional substrate components. However, the different types of wood processing create different types of wood substrates with all different hydrophysical properties. The three main types/procedures of processing wood into substrate components are hammer mills, disk refiners, and screw-extruders. While proven to be successful on a broad/commercial scale, one of the common problems with wood substrates during crop production is their tendency for the upper surface of the substrate/pot to dry out more quickly than the rest of the container, causing growers to over-water plants or possibly not water enough. This confusion for proper irrigation of wood substrates is why I want to study evaporation characteristics of the three types of processed wood, in varying ratios to see how much product can be used without sacrificing desirable substrate characteristics. After quantifying the evaporative and hydrological properties, I also plan to analyze the effect that alternative containers (non-plastic) have on substrate/plant water loss during production and post-production settings. The horticulture industry is continuously expanding its knowledge on how to continually improve the sustainability of growing practices and how these new practices may influence traditional and novel production techniques. This is what drives me to research sustainable methods of horticulture production to best understand how these new materials for substrates and container production will affect our growers and allow them to produce their production as efficiently and sustainably as possible.

Rachel Edwards