Vertro- H is a  mixture of 75%,  by volume,  of our  high quality  Vertro  Biochar  with  25%, by volume,  of Mt. Holyoke volcanic,  paramagnetic,  basalt  flour mined  from the  Mt. Holyoke  range in  Western Massachusetts.  This mixture provides  all  the  benefits  of  high  quality  biochar  as  well as  important  minerals to  replenish depleted soils.  To ensure  the best results, mix Vertro H  50/50, by volume,  with compost,  compost tea,  or other  microbe rich source to  charge  the  biochar  prior to use.  If this is not done, the strong adsorption activity of the biochar may reduce it's effectiveness in promoting soil microbial activity. Available in 40 cup bags.