I found what look like spider mites crawling around in a hole at the bottom of one of my pots. It's my only plant that isn't in a smart pot so the rest don't have holes to check but I couldn't find any mites on the leaves or any mite damage on any plants. I have mighty wash from a while ago but I'm wondering if a spray will do anything since I can't find any on the leaves. Should I do some kind of soil drench? Thanks guys.

how big?

How in the world did you see it? Are you sure it is a spider mite?

they are tiny little critters........ leave little yellow/white specks/spots on your fan leaves....... if you do have them on one plant....... you most likely have them on all your plants......... warfare is reqiured to eliminate.......... don't even want to talk about how I know........... they don't like cool rooms

Very small and white I was poking my finger looking for roots in the fairly big since it's a 20gal pot area of the hole that comes up on the side of the pot so I was looking really close and saw these.

20 gal pot....... wow....... must be some big plant......... I think it is safe to say it is not a spider mite though

I've had spider mites a few times in the past so I know what damage to look for and luckily have good enough eyes to be able to spot them on the under sides of the leaves and I couldn't find any. I'm thinking if I treat like I have in the past it won't get the ones in the soil. Are they even harmful if they aren't on your plants?

Yea it's a very large plant it has a 600w to itself

if they are kinda transparent white and ONLY in your soil id bet they are NOT spider mites but rather soil mites, there are a handful of soil borne critters that are infact beneficial like predatory soil mites and springtails, i cant say for sure but they may very well be predatory soil mites that actually hunt through the soil for other insects and molds/fungi and eat them. if i was you, predatory or not, i dont like insects in my soil or near my plants, get some Azamax and do a mild soil drench, after a few days they will be unable to reproduce and die off.

Yea that description sounds right. I've heard azamax can be harsh on plants and yellow them a bit in cases. If it's probably harmless should I not worry?

I would say not to worry. But that doesnt mean i would also say do nothing. Azamax ..follow the instructions and like said before do a light drench...IMO
good luck

any chemical on or in a plant is bad! TLO!

We need to know what they are so we know how to treat. You sure don't want to spray your plants if it is a root dwelling guy. Thrips are white, but they don't live in the soil. Is your soil on the wet side most of the time? We need more info.

going out on a limb here but id say he needs to let his plants dry out far more, when i didnt let mine dry out i got soil mites, fungus gnats and springtails like hella crazy, i did some research (which i highly recommend you do as well, look for pictures that match what you have) and found what looked like the mites i had in the soil and they were predatory, infact after reading that i looked longer and deeper in the pots and actually found a little force of mites swarming a gnat larve, and just a minute later the larve wasnt moving anymore, so i checked the mites off as non threats to my plants, i also read up on springtails, again non threats, they eat bad molds and fungi in the soil, both of these the mites and springtails are actually signs of healthy soil, however i did still have fungus gnats so i went with the azamax treatment, and i actually went with the strongest strength soil drench mixture in the azamax book, just 2 days later there was 0 movement in the soil.
also as a side note Rosebud you are half right, the mature thripes that do the visable damage to the plant are white or slightly tanish and do not live in the soil, however when ready to reproduce the mature thripes go into the soil and lay their eggs, the larva and immature form of thripes live near the roots and eat them, thripes are hella annoying and can be super destructive just like spider mite, but they effect the entire plant from roots to leaf tips.
all in all unless you have fungus gnats, these white-ish soil mites arent a threat to the plant, but still i prefer to control whats in my house and i dont like little critters, good or bad, i still highly recommend an azamax soil drench just to be 100% sure there arnt harmful critters like the bad soil mites or root aphids, or fungus gnats in your soil. better to be safe then sorry i say.
i would also say to modify your watering schedule, lengthen the time between waterings by a few days, MJ for one needs a wet/dry cycle, and second making sure your soil drys out enough is key to controlling the insects, if you keep the soil wet enough your just keeping the insects habitat in the perfect conditions for them to thrive and populations explode uncontrollably, let the soil dry out well enough and the little insects will die off naturaly, they depend on the proper conditions, and a proper wet/dry cycle destroys the perfect constant conditions for the insects. it took me a while to get used to waiting longer between waterings but in the long run your plants will thrive and the insects will never be able to get a foot hold to thrive.

I agree it might be because my soil is on the wet side. This is the only 20gal plant I have and it's a different strain than the others, lemon skunk that seems to grow faster than any strain I've ever grown and it's huge and sucks water accordingly like over a gallon a day and the top soil is dry a couple inches down but I'm thinking maybe it hasn't grown into its pot completely yet so the bottom layer stays wetter than the top. This is why I was checking for roots in the first place and when I was it was on the wet side. But again it was at the holes right after I watered so that could have contributed to the sogginess.

Stick a pencil or something longer and poke about 4-5 holes in your pot. Let the plant dry till starting to wilt. Get some sand and put on the top of the pot. I have have never had thrips in soil. Mine come in as adults...lol Knock on wood haven't had any bugs in a long while. Make sure your fan is blowing on the pot too and the leaves. Greenest of mojo

well the thripes you see are the mature adults that can float with the wind, its hard to see or even find the larve, they are so small and chill at the root zone so its hard to see them there but if you have adults you defently have youngins eating roots, either way thripes are easy to get rid of, Azamax is the champion of champions for insecticides, iv also done foliar and soil drenches with it and neither method caused harm to the plants, im sure if you go overboard with the mixture it could harm the plant but i have yet to experience any plant problems after treatments.
i agree with rose you should defently poke some holes from top to bottom in your soil, since its a 20gal you may need more then 4 or 5, just keep them evenly spaced and try to avoid getting too close to the center of the root ball to avoid damaging the roots while poking some breather holes. and you may be right reguarding the plant not being fully grown into the pot, let it go till it starts to wilt, as long as it isnt wilted for more then say 6 hours it will bounce back just fine, another idea, now im not sure if its a smart pot or not but if you can lift the pot up and off the ground even just an inch to allow excess water to flow out and stay away from the bottom so it doesnt just sit and keep the bottom of the pot wet. just another idea to help the soil dry out more. typicaly a few inches deep of dry soil is enough but since its in a 20gal pot theres a ton more soil that needs to dry out. besides an azamax treatment letting it dry till the plant wilts will defently help kill/control the critter population. i know azamax is kinda of expensive but its totaly worth every penny. i used 3 other insecticides before i used azamax and none of them took care of the problem like azamax.

Thanks sunkard and everyone for all the detailed replies and explanations. Much appreciated! My friend who grows and knowledge I respect told me he increased his yields when he started watering smaller amounts daily as opposed to drenching and waiting a few days so that the plants metabolism sped up and it had more wet/dry cycles so I started doing this a couple grows ago. It took a while to get used to watering a lot less per watering but I think I'm getting fairly used to how much they use daily and if I skip a watering one night some are droopy the next. And sometimes when I do think they're too heavy still I'll let them go another day. But I'm wondering even if I was watering the perfect amount everytime would this method just naturally keep the soil moister more than the traditional drench and wait 3 or so days?

Any thoughts on the almost daily watering?

Azamax is the stuff, kills them good....wear a good mask when you apply it, not good for humans