They do nothing for the soil but they are predators on the larval [soil] stages of common indoor pests.

Micorrhizae [fungus] are good for the soil itself.
stinkyattic Reviewed by stinkyattic on . Is This Soil Infested? . On opening my bag of soil which has been in the fridge since I last used it, I saw a couple of tiny "worms" wiggling about. In fact, they were about the same size and transparency as the first small, translucent pistils on a girl, thin, transparent, about 3mm long and maybe half a millimeter thick. I've used the soil from this bag before, the only thing that happened was I found one greenfly once, who met a quick and untimely death. I threw the soil away. Should I have? . Rating: 5