As someone who has had massive problems with spider mites let me give some advice. Anyone who says to abandon ship is silly(unless they are just infecting everything else). At the very worst you can make some tincture if you cannot smoke it. It might cost you a little money but you can basically salvage any grow from the little fuckers. They for the most part, will not attack the buds if your pot is dank at all. The non psychoactive trichromes on the bottom of leaves contain a natural miteicides and insecticides and gum up their mouth parts when they try to consume them. They do not like the buds and will leave them alone, especially if they showed up after a lot of your crystals have formed.
I have tried every homemade solution there is and unless it's a REALLY mild infestation, its not worth the time or effort. Go out and buy an aerosol spray, something that has Pyrethrins in it. This stuff will kill anything it touches and has a half life of like 6 hours in light so you can use it really close to harvest, especially given drying times and such.They make pump sprays with pyrethrins in it but its WAY harder to erradicate all the mites because you have to get under each leaf by hand where as sprays tend to fog and are much easier to use, although WAY worse to inhale so take proper pro-cations. A company named Prescription Treatment makes a Pyrethrum TR BOMB that can treat 3,000 sq. ft. and only costs about $20 where I live. The pyrethrins concentration is lower in the BOMB but it also has an ingredient Piperonyl Butoxide, Technical which helps the fog dissipate and spread out better and will increase the effectiveness of the pyrethrins, especially on eggs. It is a bomb but you can break a peice off and use it as a normal spray if you have the proper P.P.E. on. I thought I wasn't going to use it all but I ended up doing so. If you have good ventilation I would just bomb the whole room, with the ventilation and lights off.
As I just said spraying do any spraying or bombing after lights go off of course, to avoid burning. This will also extend the effectiveness of the spray because it will not break down in the light immediately and will be effective all night. Turn ventilation systems off for a few hours right when you spray, but I wouldn't leave that off all night. You will notice webs on the buds and leaves and such once they get sprayed down. Don't worry about it, all the mites in them should be dead and the next step will get rid of the webs.
Once you have sprayed with that go get a product called Azamax from General Hydroponics or the generic alternative.. aza..crol? or something. The active ingredient is Azadirachtin which is basically the active ingredient in Neem oil. This stuff is not cheap per say but works wonders. You can also mix it with water and water with it to treat for fungus gnats and other soil born larvae. The hrdroshop I went to said I should do this for the mites as well as spraying but that's not what the instructions imply and it takes way more of the product and I didn't do it but don't have mites anymore so... yeah.
Anyway it's great stuff, mix it right before you use it and only mix as much as you are going to use because it breaks down in water. I always just use the most concentrated spray the instructions say and it never burns my plants or anything. The night after you use the bomb or spray with whatever else wait for the lights to go off or spray a few hours before they come on. They just need to be dry by the time the lights come back on, or they WILL burn. Now spray the shit out of them. I try my best to spray every surface at least twice to the best of my ability. Make sure you get the undersides because that is where they primarily live and reproduce. It is time consuming, it sucks, but you don't have to ware a mask and it doesn't irritate my lungs or skin, and it works... so it's totally worth it.
Spray them down every 5-10 days, and they will quickly be gone. If they are a constant problem or you are the one bringing them in with you may need to continue spraying but for the most part 3 or 4 applications should do it. After which something like lady bugs would actually do good at controlling the population.. but they will never get rid of an infestation. You need a LOT of parasitic mites if you want that to happen. Azadiractin is an anti-feedant, an insect growth regulatior, an anti-ovipository, and a repellant. It is OMRI certified, not much more expensive then regular neem oil, and by far the best product for controlling mites I have ever used.
Given all this even if you don't get rid of the mites in time for harvest, fear not. I had a couple harvests before I figured out a good way to eradicate them. Try to spray the webs down and away a couple days before you cut them, while the lights are off, with just plain water if you haven't had a chance to do any of the above. As long as webs are not on the buds at time of harvest things will probably be okay. Cut off any horribly infected leaves the day before they get moved to dark, try to really reduce their population as much as possible by removing leaves they are on. Make sure to move the plants to dark a day before you cut for other reasons but it also encourages a lot of the mites to jump ship before the cut. Once it is cut hang it upside down, from experience most of the the mites will collect at the base where it was cut collecting moisture. I always sprayed them down at this location periodically with rubbing alcohol.
The next step is to manicure before its dry, because it is away easier to see the mites and infected leaves. Manicure the shit out of the pot. It will take forever because you can't just clip the tips of leaves. But I have sold stuff that was horribly infected but by the time I manicured it all the kid said to me was that i was manicured really well and that he got a lot of complements on the taste. If you are willing to put in the time, I doubt your crop is ruined.
Sorry for the really long post.
