Due to increasing costs and availability of suitable container substrates for nursery and greenhouse crops, a new substrate made from ground tree logs is proposed. Whole pine tree logs are chipped and further ground in a hammer mill to a particle size that meets specific container substrate requirements of a wide range of plant species and plant sizes. Preliminary studies have shown that a wide range of plants including marigold, poinsettia, geraniums, and tomato, grow well in ground pine chips compared to a traditional peatbased substrate. Root growth has also been shown to be higher in ground pine chips than in a peat-based substrate. However, before ground pine logs (pine chips—PC) can be recommended as a container substrate, nutritional and irrigation requirement during production and marketing must be addressed. Experiments will be conducted to: 1) determine ways to construct PC to optimize physical and chemical properties, 2) determine nutrient requirements of PC during production, and 3) determine water requirements of PC for plant maintenance during production and marketing.

Given a positive outcome of the proposed research, and other studies related to other issues, ground pine trees could quickly become an important substrate for the greenhouse industry. Due to a price advantage alone, ($15.00/cu. yd. for PC versus $40.00/ cu. yd. or more for a peat-based substrate) many growers have indicted a definite interest in utilizing ground tree logs as a container substrate.

For further information contact Dr. Robert Wright at wrightr@vt.edu