Pine Tree Substrate (PTS) an Alternative to Peat, Bark

Dan Mullins
Commercial Horticulture Extension Faculty
Santa Rosa County

Researchers in the Department of Horticulture at Virginia Tech, headed up by Dr. Robert Wright, are using whole pine trees to make a new nursery potting material. Word of this product is spreading rapidly in the industry and it is becoming known as pine tree substrate (PTS).

The loblolly pine was found to produce the most stable substrate product and best plant growth among 12 tree species that were evaluated. Photo Credits: Dan Mullins, Santa Rosa County

To create the substrate, whole loblolly pine trees are chipped and then a hammer mill is used to break the chips down to smaller particle sizes. Various screens are used with the machine to yield wood particles of specific sizes for growing different kinds of plants. The material is then amended with lime, slow release fertilizer and a micronutrient formulation according to the plant genera being grown. Research continues on this new product.

So far, 51 different genera of plants have been successfully produced in PTS by Dr. Wright and his team. The product has been named Woodgro and a patent has been applied for. There is much interest among growers and commercial substrate producers.

Calculations based upon the cost of pine chips at five to six dollars per cubic yard make it conceivable to produce this nursery substrate for less than $15 per yard, compared to over $40 per yard for some standard peat based products.

According to Dr. Wright, PTS could allow for the decentralization of the horticultural substrate industry and associated transportation costs. Commercial substrate producers could locate near where nurseries are concentrated and where pine trees are grown in abundance.

This new product should be of interest to nursery managers, garden center operators and gardeners. The latest information concerning PTS can be found in the August 1, 2008 issue of the American Nurseryman magazine, pp 26 – 32.