Extending Pine Bark Supplies with Wholetree and Clean Chip Residual Substrates

A limited supply of pine bark (PB) over the past several years has caused concern among many nursery producers. In continuing the search for alternative substrates and working to quantify the extent to which substrates can be amended with high wood content alternatives, this study was developed to evaluate substrate treatments comprised of PB with 25, 50, and 75% clean chip residual (CCR) or WholeTree substrate (WT), as well as 100% substrates of each high wood fiber substrate. By 180 and 365 DAT, pH and electrical conductivity (EC) values for all treatments were similar to those of the 100% PB control. Growth data at 365 days after planting (DAT) showed that with all nursery crops tested, nursery producers could use 75% CCR or 75% WT in their standard PB substrate with limited impact on crop growth. The purpose of this study was to allow nursery producers the opportunity to become comfortable using CCR or WT as amendments before switching completely to 100% alternative substrates.