I was gonna say that can be the only downside! It really depends where u get them from! I have a local place called txwormranch but i just cheap stuff and add my own beneficial bugs! Good thing is they tend to hang around depending on what u use! This soil in these lil pots i used some old soil from my last and just added compost and then added it back to top half of pots next run and it was enough to colonize these pots with predator mites! Soil started out in diff pots in a diff tent but 1 handful in each pot was enough!
Took this other day but u can see em crawling all over!