7,500 mycorrhizal propagules/spores/units in this bag. Glomus Intraradices: The world's most effective mycorrhizal species, forms the strongest bond with your plant. Biochar: Promotes a healthy microbial population and accelerates mycorrhizal effectiveness. Kelp/Humic Acid: Acts as a growth stimulator, helps plants fight disease, and increases plant yield. Worm Castings: Organic plant food that plants need to grow.