Pine Trees Make Good Container Substrate
Robert Wright, professor of horticulture, examines poinsettias grown
in WoodGro, a substrate made from ground pine trees.
Researchers in the Department of Horticulture have developed a new container substrate from ground pine trees that is a promising alternative to conventional substrates made from peat moss or pine bark.
Peat moss and pine bark have been used as the primary base for most greenhouse and nursery substrates over the past 30 years. According to Robert Wright, professor of horticulture, these materials serve as excellent substrates, but their cost has been increasing rapidly due to a number of issues.
The environmental concerns of mining peat moss and increasing transportation costs could limit its availability and use. By-products such as pine bark and sawdust also have limitations due to their availability and inconsistent quality, which is due to the variety of methods used to harvest, process, and store them.
Taking these factors into consideration, Wright and his students have developed a new container substrate product called WoodGro that uses the entire tree. "We currently use pine bark and sawdust as substrates; why not grind the whole tree?" said Wright. "By making the substrate from whole trees - a renewable resource - we can have better control of the product and make it to our specifications."
The substrate is made from wood chips produced from loblolly pine trees. These chips are similar to those produced by the forest industry and used for paper manufacturing or as an energy source at power plants. The chip size is reduced further to a particle size suitable for container substrate.
Results from Wright's research demonstrate the product's feasibility as a substrate for growing greenhouse and nursery crops. However, Wright is quick to note that due to the different physical and chemical properties in the pine-chip product compared to the pine bark, more research is needed to determine specific irrigation and nutritional management strategies, as well as further refinement of manufacturing techniques.
Preliminary estimates indicate that the cost of this new substrate will be considerably lower than peat moss substrate at $15.00 versus $40.00. According to Wright, the creation of a wood-chip substrate will help to decentralize the substrate production industry by providing more local or regional sources of container substrate near where trees are grown. He has received interest in opening a production facility in Southside Virginia, an area with an abundance of labor and pine trees. This would create jobs, form another market for timber, and contribute to overall economic growth of the area.
Growers have already shown interest in using the product and are asking when it will be commercially available. Wright has applied for a patent for WoodGro and has formed a company to continue research and commercialization.