Found this on another forum, maybe it will help...
Here's a few tips:
-Don't bring any "stray" plants into the growroom without giving them a 2 or 3 week quarentine 1st.
-ALWAYS wash your hands before going into the growroom.
-Mites--indeed most insects--build up a resistance to certain types of insecticides rapidly. You need 3 types of insecticides and rotate their use. Pyrethium and neem-oil based are 2 types. Insecticidal soap is another one. Make sure they are non-toxic to humans. Use a light mist of them every week, followed the next day with plain water. But don't use them during flowering.
-Mite eggs can hide in the smallest crevices, therefore the floor should be either linolium or put a tarp down.
-Mites thrive in warm environments. Keeping temps at 65--70F will reduce their reproduction rate.
-Have a pair of overalls that you only wear in the growroom.
-Inspect the plants weekly, especially the undersides of leaves.
-Avoid having the plants touch or almost touch each other. And use sticky tape (available at large plant nurseries) on the planters. This will keep the mites from spreading from plant to plant in case some gets in.
Of these tips, the 1st is the most important. The most common way for mites to get inside in by hitchhiking on an infested plant.
