Spider Mites

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Spidermites are arguably the #1 enemy of cannabis plants. So I've started this thread for everyone to post there own remedies to combat these bastards. I'll go first.....

Spider mites are probally the most prevalent pest to inside growers. There are many ways to erradicate these critters but can be broken down into two types of methods. These methods are chemical or organic.

With any pest erradication program where you are depending on a chemical, be it organic or synthetic, it is best to cycle between three different pesticides for optimal results and to ensure the critters don't build an immunity to them.


I've found that spraying with a pyrethium based spray to be very effective. Buying one that is combined with garlic would work as a repellent to these pests as well. The only problem with this is recently there have been shown to be pyrethium resistant mites. The treatment regime with this should be at least one spray a week, but no more than two. Don't think that more poison concentration will help remove them faster as it may only lead to your dissapointment as you see your plants suffer from burning. When spraying make sure that the underside of the leaves get just a much of a generous spraying as the tops.

If things have got right out of hand and nothing else seems to work you can count on flea bombs purchased from local supermarket. Be warned as they are full of dangerous poisons and the use of these should be greatly avoided within the last few weeks before harvest. The regime for these are one a week until problem solved, this is usually one week but occassionally you will need the second one. Make sure to turn off all exhaust fans for two hours from the time that the bomb is initially going off. After this two hour period is over turn back on exhaust fans and air out room thoroughly. Do this when the lights are out as a room full of fumes has a habit of exploding when a heat source or spark is present. These are so effective because the actually break into every part of the breeding cycle killing mites in all stages.

The recent success in mite eradication has come from the availability of a pesticide called Avid. Many growers swear that this is the only thing that really works without reinfestation. It is extremely important to kill them off completely and not start breeding resistant populations.


The most popular of the organic pesticides in recent times is neem oil or neem based products. These do work well in most cases. The treatment regime for these is no more than every three days and should be avoided in the last couple of weeks due to the fact that it can give the flowers a dirty flavour when consumed.

One completely chemical free way to eliminate mites is by manipulating the humidity in your grow room to above 80-90% for no more than three days. Any longer than this and you're asking for mold. This works because the mites absorb the extra moisture in the air and literally explode due to absorbtion of too much water.

Another manual way to go about things is to go in every day and give the plants a liberal spraying with plain water on both tops and bottoms of leaf sufaces. This physically knocks them of and disturbs there patterns as mites may not move for three days at a time. With this, as with the previous method, beware of mold.

With any treatment using chemicals be carefull to follow instructions and follow good safety procedure. It's not the best feeling to be stuck in bed for a day due to inhalation of chemical vapours

Integrated pest management (IPM) is an eco-sensitive way to manage pests of all kinds in the garden and landscape. It is an approach that focuses on preventing pest problems by growing healthy plants in well-designed landscapes. If pests do occur, there are a variety of ways to manage pests safely and effectively.

Prevention is the cornerstone of IPM. This means choosing the right plant for the right place, using pest-resistant varieties, looking after soil fertility and watering properly. "Look before you leap" is a rule to live by in IPM. This means regularly checking plants for damage and making sure that suspected pests are correctly identified before taking any action. This is important because similar damage can have different causes (not all of them pests!). Also, many insects found on plants are beneficial – they are there because they are eating the pests. If treatment is needed, there are many different methods, including:
biological controls: beneficial insects, nematodes and microorganisms that attack pests are sold at some local garden centres;
physical controls: floating row covers, screens, sticky traps (for insects), mulches, hot water, hand pulling (for weeds);
cultural controls: using resistant varieties, crop rotation, and pruning;
chemical controls: naturally occurring or synthetic pesticides.
Using Pesticides
There are many different kinds of pesticides (insecticides, herbicides, fungicides, etc.) with active ingredients that range from the extremely poisonous to the completely non-toxic. If other methods do not keep pest numbers down to acceptable levels, you may need to use a pesticide. If so, then choose the least toxic, low-risk product and limit its use to the plant that has the problem.

Bacillus thuringiensis (Kurstaki) or Btk

Soil bacteria which produce spores and protein crystals that when ingested, kill caterpillars. However, Btk is non-toxic to other insects, animals and people. Used on leaf-eating caterpillars in greenhouses and gardens.

Dormant and Summer Oils

Mineral oil acts on contact via the suffocation and disruption of the target insects' physical processes. Dormant oil is used for over-wintering eggs of aphids, some moths, mealy bugs, pear psylla, pear and rose slugs, scale, spider mites and is best applied to deciduous woody trees and shrubs after leaves drop and before the new growth starts. Summer oil is used on mealy bugs, rust mites, scale, spider mites, and white flies. Check label or test spray to see if the plant is oil tolerant.

Insecticidal Soap

Biodegradable fatty acids that act on contact against insects and mites; used on aphids, earwigs, mealy bugs, pear and rose slugs, psyllids, scale, spider mites, white flies and other insects; outdoors and indoors. Such soap is phytotoxic to some plants, so check the label first.

Silicon Dioxide (Diatomaceous Earth)

Ground-up fossilized shells of diatoms; acts on contact on most insects by piercing their skin and causing them to dry up. Non-toxic to people, animals, birds, fish and earthworms. Limit use on outdoor plants to spot treatments.


Extracted from pyrethrum daisies, this pesticide acts on contact; used for crawling and flying insects on plants, pets, in structures, indoors and outdoors. Modest toxicity. Avoid inhalation or contact with skin or eyes.

Fatty Acid Herbicide

Fatty-acid compound that acts on contact to kill foliage of plants. Used to control annuals and/or provide suppression or top-kill of some perennials. Avoid spray drift on desirable plants.


Sulphur provides broad spectrum control for fungi and mites. Use on foliage for black knot, black spot, leaf spots, powdery mildew, rusts, apple and pear scab and others. Also controls russet and rust mites. Use only on plants tolerant to sulphur.

Lime Sulphur

Calcium sulphur compound; used for control of fungi, mites and some insects; used as a dormant spray or growing-season spray for fungal diseases as well as scales, spider mites, rust mites, aphids mealybugs, and peach borers. Phytotoxic to most actively growing plants. Check label and use in correct dilution.

Pesticide Safety Tip

Before you use any pesticide, it is critical that you read the label and throughly understand what the product contains in terms of active ingredients, instructions, cautions, safe handling and proper disposal.
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Re: Spider Mites - by Stix

Organic home remedy:

4 jalapenos
2 lemons
2 garlic cloves
2 drops Dawn dishwashing liquid
4 cups water - PH corrected

Throw all except water in a blender and mix until pulverized. Add water and blend well. strain thru a cheese cloth or other filter to get the chunks out and mist your plants with it. Test it first in a small area in case it burns your specific strain.
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