How to Get Rid of Spider Mites on a Cannabis Plant

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Spider mites are a tiny insect that will breed very quickly, and destroy your crop in a very short space of time. If you suspect that you have an infestation, then you have to act fast! So let’s not waste any time and get straight into how to get rid of spider mites on a cannabis plant.

Before you start using any pesticides, you have to be sure that the bug you are about to fight is spider mites. Having an accurate diagnosis of the problem is half way to fixing it. If you have already confirmed that you have spider mites, because you have seen their webs on your plants, it may already be too late for your crop.

How to Identify Spider Mites on a Cannabis Plant

When spider mites eat, their tiny mouths puncture cell walls in your cannabis plant leaves. They will suck out chlorophyll and other juices. This will cause small white dots to appear on your leaves.

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You will see these symptoms before you see bugs. Spider mites are very hard to see with the naked eye. They also reproduce very quickly, which means if you do not act quickly, your grow room will soon be infested.

If your plants have become infested with spider mites, maybe you would have noticed webbing around your plant. This is where these mites get their names. The will produce a web, to weigh down a plant that is dying. The plant will collapse under the weight of the web, and land onto another plant.

Spider Mites on a Cannabis Plant, spider mite web

The mites will then walk onto another plant and begin eating that one too. If not identified, and treated quickly, spider mites will kill your whole crop! It can go from one day everything being fine, to the next day everything covered in mites, be vigilant.

Get up Close

Spider Mites on a Cannabis Plant
Spider mite and 3 eggs.

Try using a magnifying glass on the under sides of the leaves. With enough patience, you may be able to see a small mite. These mites can be less than a millimeter in length when fully grown.

To understand how to kill spider mites on a cannabis plant, you should understand a little about their life cycle. This will not be a one treatment job and then it’s done. To kill them all, you will need numerous treatments spaced three days apart.

If you have any questions about spider mites or any other pest, then feel free to ask for help in our cannabis growers forum

The Life Cycle of a Spider Mite

Spider mites go from their eggs to sexual maturity in a little over a week. At this point, they will be able to lay more eggs and the cycle continues.

Spider Mite Life Cycle

A fully grown female spider mite will lay up to 1 million eggs in a month!! Eggs will take around three days to hatch once they have been laid.

The larva of the spider mites will start to eat your leaves and plant matter, and after a few days, will “molt” into is protonymph stage. This process continues over the next week until the spider mite has reached sexual maturity. She will breed, and lay more eggs, which will all follow the same cycle.

If not caught early, an infestation of spider mites can appear to come out of nowhere. Thousands of eggs can hatch overnight, and within a week, half those eggs, will lay thousands more eggs. If you have identified spider mites on your cannabis plant, act quickly!

Killing Spider Mites on a Cannabis Plant

Spider Mites on a Cannabis Plant

Spider mites will lay eggs on the underside of the leaves, so they can be hard to get to. The adult female spider mites are the biggest threat. You have to reduce the amount of eggs being laid first, so you have to kill the females. They will be your main target.

Before you begin, remove your plants from your grow room. The grow room will need to be cleaned with disinfectants whilst the plants are not in there. Clean the grow room, and then move onto fixing the plants. No matter what method you choose to kill the spider mites, you will have to ensure your grow room is clean of any bugs too. It’s a waste of time to treat your plants, to then put them back into an infested grow room.

Pesticides for Killing Spider Mites

Pesticides can be damaging to your health, and the environment, and it is important to choose the right one for the job. Use any of these pesticides during vegetation, and early flower.

Home Made Neem Oil Pesticides


Neem oil pesticide is a very good effective and organic way to treat pests on a cannabis plant. It smells pretty bad, but it will kill and deter any bugs in your grow room. This should be part of any grow room arsenal, and should be used regularly to prevent bugs moving into your grow room.

To make a neem oil pesticide at home, follow our simple guide. This pesticide will be a good tool to have. Do not underestimate how important it is to keep up with IPM ( integrated pest management). Prevention is better than cure! Buy, and use neem oil pesticides now!

Pyrethrin Pesticides

Pyrethrins are naturally found in chrysanthemum flowers. They are a mix of six different chemicals, that are harmful to insects. Pyrethrins are commonly used to control mites, thrips, aphids, gnats, and many other pests that can be found in your grow room.

There are a lot of pesticides that contain Pyrethrins. Any of them will work. You just have to apply them correctly depending on what type of infestation you have. Routine is important. To treat spider mites, use this every 3 days, for three treatments.

Using Predatory Bugs to Kill Spider Mites

In some cases, you will contract spider mites during the flowering cycle. This is a difficult situation to be in, as you don’t want to spray your flowers with chemicals. Not only will it affect the flavour and smell of your cannabis, it could cause long term health problems if you smoke these chemicals.

Introducing beneficial insects instead of chemical pesticides is an option. The bugs are carnivorous, and will eat the eggs, larva, and adult spider mites on your plants.

Though they will not eat your plants, they will of course, produce waste and leave them on your buds. If you have a pest problem, late in flower, no matter how you treat the infestation, it is always in your best interests to wash your buds after harvest.

Use predatory bugs if there is no other option. Neem oil spray will bring you good results, and washing your buds is always an option too. Now, you have chosen your weapon. Lets get onto to treating the infestation.

Correct Pest Treatment Schedule for Spider Mites on a Cannabis Plant

Remember to clean your grow room thoroughly, before treating your plants. Don’t waste your time treating the plants to put them back into an infested room. Clean the grow room, and then treat the plants.

Keep the plants outside of the grow room, or turn off your lights if you cant remove them.

Water droplets can cause burn on the leaves of your plants. Make sure your plants are not sitting under lighting when you treat them with any foliar spray.

Spray the plants lightly, on the under side, and on top of the leaves


Don’t spray the plants so much that the leaves are dripping. A fine layer of the neem oil solution will do the trick. It is important to try and get every leaf, on the top, and the underside. The more area you can cover, the more successful this treatment will be. You can also lightly spray the top of your medium too.

Apply a light breeze over the plants, and let them dry before placing them back into the grow room

This neem oil mix can be used on flowering cannabis plants, but it is not preferable. It is not recommend to treat a cannabis plant with any pesticides within two weeks from harvest.

Whenever you spray cannabis flowers you must ensure there is a breeze flowing over the buds until they are dry. If they are wet for too long they will form mould or rot.

Repeat this treatment three times. Once, every three days!

Most pesticides will not be able to kill the eggs of spider mites. We have to treat the cannabis plant every three days as this is how long it takes for spider mites eggs to hatch.

The first treatment should kill the adults, and no more eggs should be laid. But some spider mites would have survived, and a few eggs would have hatched in the last couple of days. Treating three days after the first treatment will ensure any more mites that have hatched are killed before they reproduce.

One more treatment three days after that should see the end of the infestation.

Final notes on killing spider mites

If you are heavily into flower, then you may want to consider using the predatory bugs to kill you spider mites. Whatever method you decide to use to kill the spider mites on your cannabis plant, you will have to find out how they got in the grow room in the first place.

Remember, prevention is better than cure! Find out how they got there and make sure it doesn’t happen again! Also keep up with regular integrated pest management. If your grow room isn’t a good environment for bugs to live in, they won’t live there! Read more about IPM, and how to prevent bugs invading your grow room in our pest section. If you need any further help, as usual, you can find the whole team in the forum waiting to help you out.

Sign Up to our Cannabis Growers Forum

Thanks for reading! You can find more information on anything related to growing in our cannabis grow guides. All of our guides are written by experienced growers, and members of our cannabis growers forum. If you have any questions, sign up. It is free, and we are always happy to help!

Thanks for reading Percy Growers! Stay safe, don’t have bad dreams about spider mites, and happy growing!

35 thoughts on “How to Get Rid of Spider Mites on a Cannabis Plant”

  1. I’ve been watching my crop & can say I haven’t seen a mite in ages.
    Seeing nothing bar predators witch is awesome didn’t take them long.
    they do bread at twice the speed of mites.
    i used a mix of bottled Phytoseiulus persimilis & the sachets that contained amblyseius californicus  
    I don’t know if I can say who I got them from but I definitely would recommend them as i have used there other predators for gnats & they definitely do the job.
    did order a top up but looking at them I don’t think I need them the predators have done the job already.

  2. @im_sparky sweet bro I’m glad it didn’t came across like I was being a know it all dick hahahaha. I think there is an editing window from memory, you have 8 minutes or something like that to edit the post and after that only mods and admins can change it. So yes all good, I actually use it from time to time in coco if I get a real bad gnat problem and it works wonders but always have fans off and a mask just incase I get a bit overzealous with the application method hahahaha, and I usually leave it for a day or so after applying so it can work it’s magic…can be tough in coco when you need to keep it moist though lol. Recently I have been using the hot shots dunks and they work brilliantly to keep the tent gnat free, wouldn’t work for spider mites though. I use the Ed Rosenthal herbal spray if I have mites crop up but I’m such a stickler for keeping bugs out of the grow room I will shower before I go near the tents if I have been in the gardens outside lol. If I could airlock with hazmat suits I probably would 🤣 spider mites suck hahaha.

  3. @bubblehok SOOOooo glad you caught this! You are 100% correct and this is simply an editing mistake on my part that I had not even realized I typed, so I appreciate you pointing it out. I certainly do not want to put out wrong info.  It would be nice if we could edit posts — meant to say I am not sure if it is still effective for pests once it dries out. You always diplomatic — not at all snarky, mate!

  4. @im_sparky hey mate, just so we are sharing the correct info, as far as being dangerous for your lungs you are 100% correct, even food grade DE can cause issues if not handled correctly, however DE is rendered ineffective when it becomes WET, you really want it to be dry for best effects 🙂 Hope that didn’t come across snarky or anything just wanted to point that out in case you were unsure 🙂

  5. @denizen Diatomacious earth can be really great stuff. However, and throw this out there for anyone who may not know, it is a very serious danger to your lungs should you breath it so wear a good mask. It also becomes ineffective for pests if it dries out, and of course, if it dries out it can become airborne again. Given the fans used in a grow space, I don’t use this indoors, but love it for outdoor use.

  6. I’ve had decent success using DE (diatomaceous earth) for Spider Mites. It’s a fine, clay-like powder that’s made from tiny dead organisms called Diatoms. On a microscopic level it’s really sharp and jagged and it gets inside the cracks of the Mite’s exoskeleton and fucks them up, drying them out and killing them. Contains plenty of Silica and stuff as well, so it’s apparently beneficial as a soil additive as well. You do have to be a little careful on younger plants as I’ve found it can dry them out as it’s so powdery. It’s great for spreading around an area/tent when you’ve had an infestation and want to be sure. Just another thing that’s worth having in the arsenal!

  7. If I find any and the plant is small enough or you got a big bucket. Dunk the whole plant in your spider mite solution. Turn the plant upside and dunk away.  Then using gloves rub your hand and fingers all over the plants stems and leaves.  Then dunk in fresh water. I do this method just using dish soap and veggie oil. This way all kill the adults kill most of the young and eggs.  Remember I’m pretty sure there life cycle is 3 days just like fleas.  

  8.  I had a bad infestation of spider mites. They were in my houseplants upstairs too. Tens of thousands of them. Maybe more.
    But my mother plant had none.
    Why? I used a sticky substance called Tangle Trap. It looks like rubber cement. I smeared it on the table legs of my mother set up. The legs are only 4″ tall but it was enough. I recommend the sticky stuff. There are different brands. I make yellow sticky cards for fungus gnats too. Physical barriers can work.
    I guess if you have pots on the floor it wouldn’t work.

  9. “Nuke the site from orbit, it’s the only way to be sure".
    Corporal Hicks, the film Alien. 
    Lol. Spider mites are nasty. I lost a whole harvest once. 2 weeks from cut. There had to be tens of thousands. I sterilized the place. They were on my houseplants too. I have none now.
    Now I elevate all my trays or pots, setting everything on a plywood base with legs. The legs can be 1″. The legs get coated with a sticky substance called Tangletrap, also used to make fungus gnat cards with yellow poster board. I also have a Roomba robot sweeper I set loose on my rooms.
    I think I picked them up working in my neice’s vegetable garden. If I do yardwork or am working/touring in another grow room, first thing I do when I get home is leave my shoes outside or spray them with a disinfectant like Lysol, take off my clothes and put them in the washing machine. I also have shoes I never leave the house in.
    One infestation can make you paranoid for life. Lol. 
    By the way, I didn’t know of any way to use the plants so I pitched the lot in the trash. It broke my heart.

  10. Great read, excellent process. Something that could be helpful in this process to help eliminate eggs is to wrap the soil in cling film and dunk the whole plant in a light homemade insecticidal soap. Failing that, I bring the plant out put it on its side on a table and was the shit out from underneath.

  11. Posted by: @cth1980

    I’ve also looked at the smoke bombs obviously after once tent is empty have you used these before?

    no mate i havent but i can recommend ‘hot shot’ pest control. 

    kills all living insects dead in a bout 3 days .. you could use it now but you have the beneficials which it will kill too

    make sure to vent where you are not breathing the air though (as you would a smoke bomb)

  12. Hello I have spider mite since the 26 of august on my Mainline almost 8 weeks in flower i caught I 5 min ago, I sprayed it all with 1/9 isopropyl water to kill those bitches,what do you think is it gonna work to at least finish it ? Do you have a recommendation before going to the shop should I defoliate as much as possible as well? Im already cleaning everything ,
    I’m going to look into it more, it’s the first time I have to deal with them… I also have 2 veg room going, my grow is in my baseman should I clean it all up (I have a normal family garage shelves full of stuff) 
    I clean once a week never really had any pest problems before, can someone path my back please I don’t feel I’m going to get good feedbacks…
    Kiss 💋 

  13. I can’t remember the name of the predator it’s probably one of the above mentioned. They arnt as ferocious but can live on pollen & deal with temps better.  I remember adding then to the mix to pick up any left overs the main ones missed 

  14.   If you’re worried about mold you can always increase the airflow I love following VPD charts and have run 70% with no issue on some BBWs….I just put a 12’ fan hanging from the top pointed towards the side. It made the girls dance a little ….however I will say that if you have dealt with mold in the past to be extra careful and be ready to abort everything on the first sign. 
    also heads up the predators are doing their thing but let them rock until the end of flower because you have to concern with keeping a balance these guys grew side by side in nature.. when you’re done with the grow make shure to spray everything you’re going to reuse and the entire tent with bleach at 1/10 dilution ….I’ve even heard of people with bigger tents sealing and bug bombing.
    if all else fails just switch over to no till 😆   It’s what I did lmaoo Thumbs Up  

  15. Update : no further damage found so these predators are doing their work nicely it seems 👌
    note: ideally humidity levels need to be 60 and up so not ideal for use on late flower .. I’ve turned off my dehumidifier which has got me on the right zone and ok as I’m still mainly early flower / stretch phase atm in my flower room 

  16. @toploader I’m using them at all stages but the earlier the better ..
    I wouldn’t use them after neem spray until a week or so or spray the plants with water to wash neem residues away..
    im guessing the predators don’t like neem but not sure tbh
    I have a very small amount of mites but so tricky to rid entirely as plants keep coming and going lol
     Not up for chemical treatment so nature is in the driving seat 
    I also remove the leaves that show first signs of mite damage to try slow down their spread 

  17. Posted by: cloudy_kitchen

    this is a quite a common problem for a lot of growers I have seen on fb etc 

    Wait until summer comes mate! Gotta make sure your on top of it before they show up when its warmer outside

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