Questions with Brian Jackson

Dr. Brian E. Jackson is an associate professor and director of the Horticultural Substrates Laboratory at North Carolina State University. He has researched wood substrates since 2005, and his work specializes in the engineering, characterization, and commercialization of these materials. He will discuss the topic “Focusing on Substrates: The Wood Fiber Frenzy” at Cultivate ’18.

Jackson: To date I have a list of 35 named wood substrates, or substrate components, that have been researched, developed, or commercialized at some point in the past 38 years. Of those, some of the current major players who produce or offer 100 percent wood-based materials would include the European-based products of Forest Gold (Pindstrup/Bullrush), GreenFibre (Klasmann Deilman), and Hortifibre (Florentaise, Aquiland, and others). North American products include Hydrafiber (Profile), Forest Fiber (Old Castle), and various pine tree substrates of independent greenhouse operations.

Jackson: There are, as well in addition to many blenders and distributors of mixes containing the above mentioned raw wood materials. These materials are not continent specific in that the European-based companies have operations here in the U.S. who sell those mixes here, and some North American companies and products are venturing overseas in their product distribution.

NM: Are there differences among the various products?Jackson: These materials are primarily different in the feedstock used to make them, tree species for example, and the method or process by which they are made. Several different machines and processes exist that make similar and different products. Other than being 100 percent wood and un-composted they are, or at least can be, very different in their properties. They do tend to have a higher inherent pH than peat or bark and they have a low pH buffering capacity so pH management is different than in traditional peat or bark-based mixes. Wood is not wood is not wood. Further understanding of the differences through product testing and analytical laboratory fingerprinting is key in expanding our understanding of their uses, potential, and issues.

NM: What has laboratory analysis and grower trial experience shown in regards to these products?Jackson: That they are more successful than unsuccessful when trialed in laboratory or grower operations; that they do require some production system and crop management strategy changes, depending on the grower of course; that they are stable materials for most all cropping systems evaluated; and the irrigation management may be more critical or important than fertility changes or management. NM: Are there potential long-term financial benefits of these products for growers?Jackson: This depends so much on individual growers, their location, the crops they grow, and their operating systems. If wood-based mixes, or components, can be readily obtained from sources close to growers, the savings on transportation costs may be the most immediate and long-term benefit.

Jackson: Yes. The potentials and possibilities of engineering wood are just now being more fully explored and tested. One of the greatest attributes of wood is its ability, ease, and consistency of being processed and engineered to yield many very different particle sizes and shapes, all of which serve different functions and can be further formulated to fit a large variety of growing systems, containers, hydroponic gutters and troughs, bags, and such. That, coupled with the vast wood resources we have in the U.S. and the variety of equipment and processing machinery that is available to make substrate materials, makes me think the future is bright. With continued grower interest, trials, and successes there will be more products added by substrate manufacturers that perform a variety of different functions in soilless cultivation systems.