Are you in veg or flower? How far along are you? Indoor/Outdoor? Soil/hydro? We need some basic info to help you better.
I've never had spider mites, but had russets and this is only part of what I used to kill em off and keep em away.
Mix 2 oz. concentrated neem oil to 1 gal warm water **not hot** (helps break down the neem oil to mix in the water) and a few drops of liquid dish detergent(dawn,joy etc). If you are running organics be sure not to use an antibacterial dish detergent. Spray the plant from top to bottom until fully saturated....and I mean like completely soaked on topsides of leaves and bottoms,stems,main stalk-everything. Treat every 7 days or whatever schedule your bottle instructs you to follow.
Heres a couple suggestions to help keep from introducing pests to your grow:
-Dont introduce any plants/clones etc into your grow until they have been "sterilized" with a hearty neem treatment as mentioned above and checked for bugs/mold etc.
-Dont share meters/tools/fertilizers etc with other growers unless you totally sanitize first. Sometimes thats not all they will be sharing with you.
-Keep a clean grow and make sure there are no dead materials laying around, standing water etc.
-Find a good preventative maintenance program for bugs and mold that works for you and follow it religiously.
