Poinsettias grown in WoodGro™

10-15 year-old loblolly pine planting

WoodGro™ is a substrate used to produce greenhouse and nursery crops in containers. It is made from wood chips produced from freshly harvested pine trees, a renewable source of raw materials.

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 using a hammermill to a produce a substrate designed to meet specific substrate requirements (aeration, water holding capacity, etc.) for a wide variety of plant genera and plant sizes at an affordable price.


Since the substrate can be ground to the correct particle size there is not a cost associated with adding aggregates, such as perlite, or vermiculite as with peat moss. We have demonstrated that a wide variety of plant genera, both herbaceous and woody, can be successfully grown in WoodGro™.

Herbaceous marigold grown in WoodGro

Woody juniper grown in WoodGro (right)
compared to pine bark (left)

The substrate can be used immediately after grinding without composting, and WoodGro™ can be produced locally where pine trees grow, reducing transportation cost associated with substrates made with peat moss.

Loblolly pine can be grown & processed in the shaded areas, close to many nurseries

The main difference in management of WoodGro™ versus peat moss or pine bark as container substrate is that more nitrogen (N) is required for plant grown in WoodGro™ due to microbial tie-up of N in WoodGro™. This is easily compensated for by adding additional amounts of N to WoodGro™ which may be accomplished in a variety of ways, as shown in the images below.

Chrysanthemum 'Baton Rouge,' above, grows better at lower fertilizer rates in peat-lite (left) than in WoodGro (right), but at 300-ppm nitrogen, growth is not different.

There also seems to be some wood toxins present in freshly ground pine trees, but with proper fertilization and irrigation these toxins seem to disperse quickly and cause only slight reduction in plant dry mass with no noticeable reduction in plant size.

Published Research

Chipped Pine Logs: A Potential Substrate for Greenhouse and Nursery Crops, HortScience 40:1513-1514, August 2005 (PDF file)

Ground Pine Chips as a Substrate for Container-grown Woody Nursery Crops, J. Environ. Hort. 24:181–184. December 2006 (PDF file)

Grinding Pine Logs to Use as a Container Substrate, Greenhouse Product News, January 2007 (PDF file)

Growth of Chrysanthemum in a Pine Tree Substrate Requires Additional Fertilizer, HortTechnology, January–March 2008 18(1) (PDF file)

Effect of Fertilizer Rate on Growth of Azalea and Holly in Pine Bark and Pine Tree Substrates, HortScience 43(5):1561–1568. 2008. (PDF file)

Pine Tree Substrate, Nitrogen Rate, Particle Size, and Peat Amendment Affect Poinsettia Growth and Substrate Physical Properties, HortScience 43(7): 2155-2161. December 2008 (PDF file)

The Landscape Performance of Annual Bedding Plants Grown in a Pine Tree Substrate, HortTechnology January-March 2009. 19(1):78-82. (PDF file)

Laboratory Bioassay and Greenhouse Evaluation of a Pine Tree Substrate Used as a Container Substrate, European Journal of Hort. Science. 2009. 74(2):73-78. (PDF file)

Pine Tree Substrate: An Alternative and Renewable Substrate for Horticultural Crop Production, Acta Hort. 2009. 819:265-272.(PDF file)

WoodGro in the News

Pine Trees Make Good Container Substrate, Connections magazine, Spring 2006

A New Substrate for Container CropsAmerican Nurseryman, August 1, 2008 Vol. 208, Issue 3, p. 26-32.

For more information, contact Dr. Robert Wright