Orchid Bark is a premium orchid medium made from granulated Radiata pinus bark. It is a stable substrate for potting and re-potting orchidsand other epiphytic type plants. This high quality, stable, long lasting, toxin free, consistent growing substrate holds water and nutrients on the outside layer of each chip. A mix of the different size of chips from 6 to 12mm provides good aeration and surface for roots to anchor to.