The Zombie plague is upon you!
This goes against the natural sprays, but I would recommend *If you are still in veg* 'BugClear Ultra Concentrate' (much cheapness too).
Not the spray bottle version (as this contains a different insecticide - the more organic Pyrethrum). Pyrethrum is good, but only works on contact (has a very short residual lifespan too - breaks down in sunlight and with water). So has its place.
BugClear Ultra Concentrate; contains 'acetamiprid', a mild Neonicotinoid.
This is a systemic and stays in the plant system for 3 months. But, it is very mild (used in the food sector etc).
One big advantage, no need for direct contact to kill (so, no long spraying routines on all leaves etc). Though, it does also kill on contact too.
If you are vegging for say 5 weeks, spray week 2. Basically, you need to time it so the effects last through veg and most of flower (but are gone by a few weeks before harvest+cure). This covers you well, and I've never had mites come in towards the end of flower (if an insecticide was previously used).
Plus, if in a tent, towards the end of flower you can drop the 'lights on' cycle below 12 hrs. Mites only breed effectively with (roughly) 12+ hours of light. Cut it to say ten, and they just can't establish at the end of flower.
Unless they are Borg Zombies, in which case ..nuke the site from orbit. Its the only way to be sure!