I'm using Happy Frog for my big girls with awesome results, I'm even using it for my other plants, and they seem to be in heaven, the stuff is primo

also....in my plant physiology class we learned about mychorrhizal fungi (actually the one you guys are referring to is most likely Endomichorrhizae or Arbuscular michorrhizae, they are highly branched arbuscles within root cortical cells, and apparently neither the cell wall or the host's cell membrane is breached (when the fungus enters the root tips, and the nodule structure is formed transferring nutrients between the fungi and the root cortical cell) I think mainly the only thing the nodules do is provide an ''extra" nitrogen source that the plant stores in nodules in its roots...but I've never seen this in cannabis