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, root cuttings 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), horticultural-grade perlite, dolomitic and calcitic limestone (pH adjuster), wetting agent and mycorrhizae ? endomycorrhizal fungi (glomus intraradices).