Pro-Mix High Porosity (HP) provides a superior growing environment for plants that require increased drainage and oxygen. In addition to Canadian Sphagnum peat moss, perlite, major-and micronutrients, and dolomite and calcitic limestone, it’s fortified with beneficial endomycorrhizal fungus to strengthen roots and increase plants’ ability to fully utilize available nutrients. This is a compressed 3.8 cubic foot bale.