over 99% of endomycorrhizal species from healthy soils have not been successfully cultured outside the soil-living-root system. What those guys propagate most probably ectomycorrhizae - which associate with trees or an endomycorrhizal that associate with crops. Even if they grow a few endomycorrhizal specials - their so-called ''inoculum'' is a poor substitution for the rich diversity of healthy soil endomycorrhizal population and thus can only have a very limited effect and only in baren dirt devote of native mycorrhizae. They show no evidence that their ''inoculate'' colonizes the roots of crop plants and not just convey unrelated to colonization bio-stimulatory effects, more importantly, they did not demonstrate a comparison of plants growing in healthy soils with native endomycorrhizae and plants growing with their ''inoculant''.
He was growing trees so he needed the fungi that associate with trees, ie. Mushrooms. He ground up those he found in the forest. You want a different kind of fungus to grow crops and vegetables called endo mychoriza which don't produce mushrooms. They are present in mostly uncultivated soils.
