Pro-Mix? HP Mycorrhizae is a high porosity peat-based growing medium. This formula ensures optimum growth, especially when high air capacity and extra drainage are required. It is ideal for water sensitive crops, rooting cutting and/or low-light growing conditions. Pro-Mix? HP Mycorrhizae is compatible with a wide variety of ornamental plant species, fruit crops and most vegetable transplants. Contains: Canadian Sphagnum peat moss (65-75%/volume), Perlite?horticultural grade, Dolomitic and Calcitic limestone (pH adjuster), Wetting Agent and Mycorrhizae ? endomycorrhizal fungi (Glomus intraradices).