Down to Earth's Granular Root Zone is a powerful blend of thirty species of beneficial soil organisms that colonize plant roots and expand into the surrounding soil to greatly increase the absorptive surface area of root systems. Mycorrhizal fungi, Trichoderma and a diverse mix of bacterial species work symbiotically to promote improved soil structure and enhanced root growth. Ideal for inoculating all types of plants and establishing biological diversity in garden soils, potting mixes and soilless media.