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How To Get Rid Of Spider Mites On Marijuana Plants


spider mites cannabisSpider Mites And Marijuana Plants

Spider mites on marijuana plants have to be one of the worst things out there. I always refer to spider mites as one of the three marijuana plant plagues, with the other two being powdery mildew and heat. Any of those three items can ruin your medical marijuana garden in a hurry. Fortunately, there is quite a bit of information about spider mites and marijuana plants.

Below are a few articles that I found by legendary marijuana grower Ed Rosenthal, along with some YouTube videos that I thought was helpful when dealing with spider mites. There is so much bad information on the internet, I hope this article narrows down your search a bit. If you have any tips or comments, please leave them below so that others can benefit from your knowledge:

Mites outdoors

By Ed Rosenthal

Will setting plants outdoors cure their mite infestation?

My plants are infested with spider mites and I plan to plant them outdoors in October to flower them. Will the wind and rain solve the mite problem naturally?
Jonny Switchblade
Jacksonville, Florida

Probably. The outdoor environment is much less friendly to mites than indoors. Wind, rain, cool weather and predators will all take their toll on the mites. To remove most of the mites as the plants are moved outdoors, spray the plants with water using a hose with a nozzle. Mites hang out mostly on the underside of leaves so that’s where the spray should be aimed.The pressurized water dislodges most of the mite population, decreasing stress on the plants. After the plants are washed, spray them with an anti-transpirant to prevent stresses that result in dehydration and wilting. Many mites and their eggs will become trapped in the thin film of drying anti-transpirant that covers the leaf.

Once the plants are outdoors for a few weeks, the mite problem should disappear.

Ganja Guru Ed Rosenthal on how to eliminate mite infestations

Question: We have been growing for more than five years and we constantly have a problem with spider mites. Sometimes we use a homemade pesticide we make from dish soap, tobacco, alcohol and water. This knocks them out for one and a half to two months but then they return. How do they get into our garden? How can we protect the plants?

P.O., Ottawa, Ontario

Ed Rosenthal: There are a couple possible explanations for your recurrence of mites. One is that they have re-colonized your garden from outside and the other is that your knock-down spray, while highly effective, didn’t get every last mite. Just one fetid female can restart the cycle.

The mite road to your garden from outside has several arteries: they can hitchhike a ride on shoes, clothing, hair or garden tools. They can ride in on the air stream or thrill-slide through an unfiltered vent system to a veritable sea of green. They can also sail through an open window or door. The easiest is garden-to-garden transfer via plant or cutting. Nothing could be more convenient; they can continue to eat while traveling.

If your garden gets re-infested during the winter when there are no active mites outdoors, and you haven’t carried a mite in after visiting another garden, you should assume that you did not totally eradicate the mites or their eggs and the survivors repopulated the green room. Mite eggs are somewhat impervious to insecticides. If this is the case, the next time you spray, instead of a single treatment, use the pesticide three times, three to four days apart. That way any survivors or newborns will be killed.

CO2 to kill mites

By Ed Rosenthal

Will enough CO2 suffocate mites in my growroom?
If I turn up the CO2 to 1,500-2,000 ppm, will it suffocate the spider mites and kill them? If it won’t, what will?

Carbon dioxide (CO2) is used by plants as an ingredient for photosynthesis. Plants combine it with water using light as energy. The result is sugar, which is used to supply the plant with building material and energy. Normally, CO2 is found in the air at rates of 350-400 parts per million (PPM) and climbing. When plants are given bright light they photosynthesize faster in the presence of air enriched with CO2. A typical level for bright rooms is 1,500-2,000 ppm.

CO2 is not a poison gas. We breathe it in every time we inhale and we breathe out a lot more of it when we exhale. When gardeners visit their CO2 enriched gardens they breathe levels five to six times greater than normal.

Mites breathe oxygen. If the CO2 were turned up a lot higher the mites would be able to breathe as long as there was adequate oxygen in the air. If they were placed in an all-CO2 environment where they received no oxygen for a few hours they would probably “hibernate” in some way. They would have enough of a survival rate to continue hassling your plants.

Oxygen-free environments have been used for grain storage with mixed results. They are much more effective in controlling rodents than insects.

There are a lot of approaches to eliminating mites. You can use registered organic pesticides such as Cinnamite, neem oil or other neem oil-based or organic miticides.


Releasing a full container of carbon dioxide into a sealed grow set-up will kill all mites and insects. But, don’t be in the room while the CO2 is being released! It would be enough to KILL YOU! I have seen this technique of bringing the CO2 to 10,000 ppm for 15 minutes to kill all pests. You must vent out the CO2 before entering the room. Two applications, five days apart, will kill all mites, pests and their offspring.





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Johnny Green


  1. I want to know if the coca cola remedy is effective. This is the first time I have ever heard of this suggestion and must say I am in a hurry to try it. We shall see?????????????????

  2. I would use insecticidal soap or dish soap solution on plants every 3 or 4 days rinsing plants thoroughly between applications. I’d use a 5%-10% bleach solution to clean the floors, walls and flat surfaces in the green room once a week with the ventilation turned on for a couple hours to move out fumes. Make sticky traps with yellow index cards smeared with a thin film of petroleum jelly to monitor pest levels. This should eliminate your mite problem in 2 or 3 weeks.

  3. Does the “CaliCleaner” really work? Habanero Pepper stuff. My plant is very wilted after spaying that for spider mites.

  4. Hello I have mites and just started to rid them-I bought 4 difffernt types of organic sprayI spraayed buds soaked them— and some thats for inside protection-sprayed the floors and bottom but not plants-I just picked early the whole plant-have 3 more flowering-1 month and a week and less but I am in a corner of bed room and hard to kill mites in carpet under bed-I heard about your idea before and wondered how well it worked for you and how you mixed up hot peeppppers how much-tobbaco and chiles and soap-I am off to get dawn soap and some habinerros. see ya thanks steamer AFTER 2ND TREATMENT i FOUND 3 BABIES 2 DAYS LATER AFTER SHAKING 4 PLANTS WITH PAPAER PLAT UNDER PLANTS-YOU CAN SEE THEM CRAWL-SECOND APP. TONITE. SEE YTA .

  5. dawn dish soap?????? I know it kills fleas and is a gentle product They are indoor plants

  6. pest control service on

    If you have ever seen an earwig in your home, you will be able to notice their slender and long bodies and also their eerie movements of the body. Something that is creepier than that is the myth that gives them their name.

  7. it will kill ur plants that’s oil and gas being burnt off and sent to ur exhaust u put gas on ur skin what happends is ur skin get irriated and burning itchy feeling ur plants like that

  8. The answer to mites is a vacuum. Use whatever you want on the plant, e.g. Liquid Ladybug, neem oil, etc. , then vacuum the plants clean. Lather, rinse, repeat. 2 or 3 days apart and I did it 3 times. I had 14 girls waste high getting ready to go to bloom, blinked twice and they weren’t virgins any longer. A bad infestation of mites. Slapped them with neem oil, and once dry, vacuumed then clean, stem to…… top. The vacuum doesn’t damage the leaves, use a push on brush attachment. I have a Dyson with good suction and they handle the procedure very well. I waited 2 days, used Liquid Ladybug and vacuum them again. A total of 3 times and they are chest high, covered with popcorn blooms and not a mite to be found. The most important thing is to catch them QUICK. This isn’t something you want to do once covered in Tricombs, but it would still be better than the alternative. bbassett@hotmail.com

  9. House Plants & Carbon Monoxide

    By Carmen Clarke-Brown, eHow Contributor

    Carbon monoxide fumes can come from burning logs.

    monoxide (CO) is an odorless chemical that benefits plants but is
    dangerous to humans when inhaled in large doses. CO’s fumes are deadly
    and give no warning before claiming lives. Running a car engine in a
    closed garage can saturate a house with carbon monoxide fumes and
    subsequently kill the house’s occupants. Plants, because they need the
    chemical for survival, absorb carbon dioxide and convert it into oxygen.
    Does this Spark an idea?

    Other People Are Reading
    Read more: House Plants & Carbon Monoxide | eHow.com http://www.ehow.com/about_6717376_house-plants-carbon-monoxide.html#ixzz267KtRnId

  10. How about hooking the exhaust pipe up on my car and pipe it into my sealed room out side for say 15 minutes. Wont that kill mites and all bugs? being serious. I dont know if it would harm the plants or not.

  11. I have been growing for years and my greatest success was when I discovered that a few drops of dish detergent in a spray bottle works great! I mist the plants everyday and I NEVER have a mite problem.

  12. OR everyone at one time ,say 4:20 on one day, say 4/20/12 and then go to the police and lite up for a mass “smoke-in”. think of it 100s of thousands in every state in every nation!

  13. David Miller on

    you can also use any white oil or a mild soappy water and chilli or hot peppers, garlic chop everything up fine and put it into a spray bottle. and a way you go. nice clean no worries about
    over spray.

  14. river rain flowers on

    saw the co2 method fail miserably on weed wars…bioneem works well from neudorf..fullove

  15. Azetrol every other week.  what more needs to be said?  :-)  Nothing but success with it!!

  16. Linda Schoeffler on

    I’ve grown outside and indoors for 7 years. 2010 I got more than enough in my outdoor grow to last the year and didn’t do indoor. I planned on the same fabulous crop in 2011 – did everything the same, but I got mites – outside.  I live in a typical subdivision, my next door nieghbor had 25 plants and no mites, Yet I did and they were on all my plants.  Well, the plants were over 12 feet and I’m 5-2 and can’t stand on latters cuz I get dizzy and I’m old. (LOL)  I treated with a Monterey product called Take Down and then ice water at nite and early am before the sun.  I was already budding and couldn’t really do much more than maintain my treating and hope for the best.  My crop was about 2/3 of what I got the year before, it smoked great, looked great and smelled great.  But I saw the mite move under my hand held microscope and was unable to smoke my own weed…for several months. LOL  This coming year, I’ve trimmed eveything near my grow area and will treat with a strong mite killer.  I will dip my plants in neem oil until pre flower – about every 2 weeks, unless I see a mite.  No one at any of the dispensaries or hydro stores believed me I had mites outdoors…they convinced me I didn’t when In my mind, I knew I did.  My entire yard will be mite free and I willl only use Organic on my plants (cannabis) and a very strong mite killer on everything else.  I have a stack of shower caps I will wear and I will keep my dogs away from the grow area as best I can. And I will keep my distance when I sing to them at nite! LOLOL

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