can the plants be moved or are they stuck where they are?
You can mix 1/2 cup of bleach with a gallon of water then pour that into a spray bottle and mist the plants, focusing on the undersides of the leaves.
Allow it 4-5 min to sit on the plant, then rinse the plant with clean water before putting them back in the grow area. Dont let the bleach sit on the plants tho, will cause spotting worse then the mites.
Another good method of control is if you have one of those hand held shower heads, take the plants into the bathtub, set the water to warm and blast the plants with water from the shower head, making sure to target the undersides of the leaves. This dislodges the adults and nymphs and possibly some eggs, but in all its just a method of control, not eradication.
You can also use a soap spray to control them. Dawn is usually suggested as its a very mild soap. Mix up your gallon of water with 1/2tsp of dawn, fill the spray bottle and attack, lol. Either way, just like above with the bleach, I suggest rinsing it off afterwards.
If you are in the US, you can hit up a hardware store and get a Hot shots no pest strip for about 8 bucks. I love those things and replace mine if I have mites or not, every 3-4 months. I've only had the mite battle one time and figured it was worth my 32 bucks a year to have this line of defense against them, cause it works!!