Shake the plant, then kill the spider mites with something that kills them on contact, like...
Proven Spider Mite Remedies
(from serious chemical pesticides to organic repellants to home remedies)
Azamax-is a time-tested way to rid your grow room of spider mites - Spray plants 15 minutes before lights out, making sure to drench the foliage under the leaves as well as the top of your soil. Use a fan to blow on your leaves to help things dry. Treat your room more than once, even if you believe the spidermites are gone. You can also add small amounts of Azamax when watering your plants, as it will not hurt your roots but will kill spider mites in the soil.
Mighty Wash-- use in a similar way to Azamax
Spinosad Products-(safe & organic)-- Spinosad products are organic and unlike many other spider mite pesticides,-completely harmless to pets, children, and plants. Unlike many insecticides, you can spray spinosad heavily on leaves and roots with basically no negative effects. Spinosad products can be used directly to kill spider mites on contact, but can also be used when watering plants to systematically kill spider mites via the roots. Spinosad is also effective at fighting caterpillers, thrips, and many other marijuana pests.
Can be used both as a topical spray like Azamax and Mighty Wash, and can also be used directly at the roots. Spinosad is an organic insecticide made from the fermentation of a specific soil bacteria (actinomycete Saccharopolyspora spinosa) and kills spider mites via ingestion or contact by effecting the insect nervous system. Spinosad can be a good choice for organic and outdoor growers, because it is very toxic to spider mites, but is less toxic to many beneficial arthropods.
Note: Most spinosad products are effective for only about 24 hours after being mixed with water, so only mix as much as you will need per application. Anything left over will be waste.
Recommeded:-Monterey Garden Insect Spray with Spinosad
Doktor Doom Spider Mite Knockout Spray---This spray is hard on spider mites, but the main ingredient-Pyrethrum-can also be hard on plants (espcially in tight spaces without much ventilation) so use as a last resort if possible. Use with extreme care around humans as the ingredients can be-toxic. Never use Pyrethrum-based products on your plants while your grow lights are on as it can-burn your plants! Avoid using Pyrethrum products on young or sensitive plants as they can get burned even when the lights are left off.-Do-cover your grow lights and vents when bombing your plants with Pyrethrum and make sure you give the area at least 24 hours to air out before you try to breathe the air. This spray can works well for a couple of plants, but you'll want a-Pyrethrum fogger-if you have a lot of plants to treat. Outdoors, Pyrethrum can kill beneficial insects too, so keep that in mind if you're using natural predators to control pests (like ladybugs). All that being said, this spray will work to get rid of most spider mites, and it kills them on contact.-Pyrethrum kills spider mites but not their eggs, so this product usually needs to be used 2-4 times (once every 2-3 days) to stop the breeding cycle and get rid of the toughest infestations.
NoPest Strips-- these emit a vapor that kills spider mites, do NOT use if you will be breathing air from your grow room. Only get these if there will be no mammals breathing in the grow room while they're being used. These are only suitable if you're growing somewhere that is NOT your living space.
Floramite-- Strong stuff with harsh chemicals,-incredibly expensive, but it often does the job when everything else fails. Use as directed and only as a last resort!
Bleach solution-(1 tablespoon of bleach to 1 gallon of 95°F, pH balanced, water in a spray bottle) - make sure to clean all surfaces of your room, and bleach them too if possible.
Alcohol and Water-mixed togther will also kill the bugs on contact and shouldn't hurt the plant as long as the solution contains at least 30% water.
SM-90-mixed with water (1 part SM-90 to 5 parts water) kills spider mites on contact and is organic (it even smells good!)
Neem Oil-works in a similar way to SM-90, though Neem oil doesn't smell as nice and will leave an unpleasant taste/smell on buds when used to treat flowering plants. There's some evidence Neem oil may be-harmful to humans-so use with care!
Homemade Pepper Spray-(or buy-Hot Pepper Wax Spray) - make at home by mixing 9 parts water, 1 part additive-free dishwashing soap, and one tablespoon of cayanne pepper. This treatment is very effective against some types of spider mites, but is ineffective against other types.
Nicotine tea-- hit or miss like pepper spray, but can be very effective against certain types of spider mite. Take 15 gram of organic tobacco and steep it in hot water overnight to make nicotine tea. You can also add a little bit of-Safer Soap. Use like any other spider mite spray.
Insect predators-- there are also insect predators such as-lady bugsthat can provide some control and reduce your spider mite numbers, but it is unlikely these will get rid of your spider mites on their own. Insect predators can be effective if you have a small problem or if you need to get to harvest and chemical sprays are not a good option.
Dichotomous earth-- Basically, this is fossil dust - sprinkle on the top of your soil, and anywhere else in your room (window sills, doorways, etc). This powder-like substance is harmless to mammals and plants, but is incredibly sharp at the microscopic level. Therefore it will tear and dehydrate spider mites on physical contact. This will not get rid of an infestation, but can help control and slow things down when used effectively.
Treat Entire Grow Area With Insecticide-- Treat complete room with broad spectrum insecticide (only do this for a really bad problem, or one that keeps coming back) - avoid this if you can!
Note: Many growers to avoid chemical sprays or miticides which contain-Abamectin-or-lindanebecause these are harmful to humans. Please take a look at anything you use to treat your grow room, follow the directions closely, and heed all warnings. Some treatments will work for some setups or types of mites, but not for others. As mentioned earlier, if you got your spider mites from another marijuana grower, chances are you will need to resort to extreme measures to get rid of your infestation.