A Guide To Effectively Prevent And Remove Spider Mites On Weed Plants

Spider mites are pests that affect a lot of different plant species. They belong to the same family as ticks, spiders, and other mites, but they are very small compared to the rest of the pests.

Among the many plants they attack are cannabis plants, especially when planted in soil. They are the leading types of insects that cause cannabis plants to get infected or die. They are very small and are often found on the bottom part of the leaf.

Also, once they start attacking the plant, they can be hard to get rid of. They have small sharp mouths that they use to pierce one plant cell after another, sucking out all the sup. That results in small orange, yellow or white spots on the leaves of the plant.

Understanding the Life Cycle of Spider Mites 

Spider mites have a very fast life cycle, and a short while after attacking your plants, they start laying eggs, increasing their population. Full-grown female spider mites start the cycle by laying the eggs.


After the females lay the eggs, they hatch and become larvae after a few days. The larvae usually have a round body and six legs. They feed for several days, seek shelter, rest, and then grow into the first nymphs with eight legs. They also feed several days, seek shelter, rest, and grow into the second nymph, which feeds rest, and grows into adults. Their whole life cycle may take a few days or weeks. If they become too many and feed on your plant for too long, there will be webbing on your plants’ leaves and buds.


How Spider Mites on Weed Plants Can Be Hard to Notice 

Unlike other hydroponics, spider mites can show up on your plants in whatever setting you grow them in. Because of their small size, spider mites can appear and heavily infest your cannabis plants without you noticing.

You might fail to notice them because they appear like dots on the leaves. The male is about 5mm long, and the female is about 4mm long. Most farmers think that the yellow, white, or orange spots caused by the spider mites on weed are due to some nutrient deficiencies, and by the time they realize they are dealing with a spider mite infestation, it’s too late for their plants.

Why Are Spider Mites Destructive for your Plants?

Some of the reason why spider mites are one of the most hated and difficult to kill pests are;

Big appetitesDespite their small size, spider mites eat up cannabis plants in a very short time, especially if they are many
Rapid reproductionOne full-grown spider mite female can produce around a million spider mites within a month.
WebbingIf the spider mite infestation is rapid, you start seeing webbing on your plants’ leaves and buds. That silk webbing ruins all the crops it is on, even after you deal with the spider mites. The silk webbing covers the whole leaves and buds, causing them to die.
Disappearing actSpider mites will have you fooled that you killed them, but they will come back a few days or weeks after and finish what they started.
ResistanceJust like the way we get immune to certain diseases, spider mites also get immune to some of the methods you use to get rid of them. If you do not permanently eradicate them, you will soon be dealing with an army of super mites. One type of spider mite, called the two-spotted spider mite, is particularly resistant to a lot of insecticides. That makes it almost impossible for weed growers to get rid of them. Spider mites are quick to take on plants but even quicker in developing resistance and completely infesting your plant. Therefore, you are recommended to use several methods to try and kill or get rid of them.

1) Identify the type of spider mite

Once you have ascertained that you have a spider mite problem, you need to know where it came from and how it got to your plants. That will help you in devising the best method to permanently remove them.

There are two types of spider mites; the run-of-the-mill and two-spotted spider mites. Run-of-the-mill spider mites come from animals or pests, your vegetable garden, or plants that are not weed plants. These types of mites are the less stubborn types, and you can successfully get rid of them using a less brutal method. The two-spotted spider mites, on the other hand, are the more stubborn ones and are specialized in attacking cannabis plants.

Therefore, you can end up using not one but several brutal methods before permanently getting rid of them. These types of mites spread from other marijuana plants or come with your plant if you bought an infested one.

They are also very resistant to a lot of the methods used to get rid of them, so if you suspect that this is the type of mite you are dealing with, roll up your sleeves.

2) Reduce their numbers

Before using any method to get rid of the spider mites, it is wise to first cut down their numbers to help make the eradication process easier. You can do that by;

Blowing a lot of air over your plants and the growing medium
Controlling the heat around the weed plants.
Spraying the spider mites.

Spider mites thrive best in a hot environment with still, unmoving air. Reducing the heat and using a lot of air on the plants will not get rid of them, but it will help prevent their fast reproduction cycle. Females will not have a conducive place to lay eggs, and mating will also be hard.


The wind can also help blow off some mites or even eggs off the plant. That helps prevent the infestation from becoming worse.

If you have the plants in your house or an enclosed room, it is better to bring them outside in an open space.

Spraying is also another effective way to reduce the mite numbers. You can use either organic or chemical products, but ensure they will not have negative effects on your plants. Some of the best products include;

Best Spray Products to Kill Spider Mites on Weed

This is one of the most effective ways and has been tested for a long time with excellent results. Spray your plants 15 minutes before you turn off the lights. Ensure that the product reaches all the parts of the plants, especially under the leaves. To ensure the product dries on the leaves, you can use a fan. Also, mix a small amount of the product with water and water your plants. That will not harm your plants’ roots, but it helps deal with the mites in the soil. To evenly spray all the leaves, use a mister.
Spinosad products:
These are organic and do not pose a threat to your pets, kids, or other plants near the weed plant. You can use it directly on a mite or mix it with water when watering to eliminate the mites in the soil and roots. You can also spray it heavily on the plant, and there will be no negative effects. Spinosad products are made via fermentation of a soil bacteria type, and they kill the spider mites by affecting their nervous system upon contact or after ingestion. After mixing with water, the products are only effective for 24 hours. Therefore mix an amount you will exhaust within that time; otherwise, you will waste the rest of it.
Essentria IC3:
This is a mix of different organic horticultural oils that are toxic not only for mites but also for other bugs and insects. For maximum effectiveness of this product, you should spray it regularly after 8-12 hours.
NoPest strips:
These are suitable if you grow your plants outside. They give off a vapor that eliminates spider mites, but it can also affect you.
Bleach solution:
Spray your plants with a mixture of a tablespoon of bleach to a gallon of pH-balanced water.
Water and alcohol:
Mix 1 part of alcohol with nine parts of water to kill the mites upon contact.
Neem oil:
Although It leaves a bad smell after use, it kills the bugs on contact. For the quality of your weed, avoid spraying on the buds. Also, be careful when using it as it may have some effect on you too.
Diatomaceous earth:
This is dust made from fossils, and its particles are very sharp. Sprinkle it on your soil and floor. It kills the bugs by piercing their skin and causing severe dehydration.
Insecticidal soaps:
These and fatty acid salts work by weakening the outer shell of the spider mites. They leave no residue on the plant and are safe for humans. Ensure you cover all the parts of the plant except the buds because they may alter the smell and taste of your weed.
Doktor doom spider mite knockout spray:
This should be used as a last resort because the main ingredient is pyrethrum, which may affect not only the mites but also your plants. It could also be toxic to you, so you should be careful. Your grow lights should also be off when using this product because it may burn the plants. Leave the place to air out for about a day before walking back in.
This should also be used as a last resort because it contains a lot of harsh chemicals. Ensure that you spray not only the plants but also the area around where you have them. That helps eliminate any mites that may have jumped off the plants.

3) Follow-up

After using any of those insecticides for the first time and you notice the mites are gone, don’t be fooled. They are somewhere waiting for you to drop your guard. Follow up the first treatment with another tougher treatment to eliminate any remaining mites.


You might want to repeat your first method before applying the second one. Do not wait for too long before coming in with the second method because some bugs might have matured and attacked your plants by then.


4) Repeat

After a few days, repeat the first and second treatment methods to ensure you wiped out all the bugs. At this stage, you might also want to remove any leaves and bugs that may have been affected. That helps remove any eggs of premature mites that might have been missed.

If you have encountered a spider mite infestation on your plants, there may be something you unintentionally did to bring them in. Prevention is the best way to say free of spider mites.

5) Indoor Prevention

The majority of weed growers bring spider mites in their growing room with new weed plants they buy or by visiting an infested growing room. To prevent that;

Use a handheld magnifying lens to check for any spider mites or spider kites eggs on the plant, especially under the leaves.
Dip the plant or spray it with a mixture of water and Mighty Wash or Safer soap.
Keep the new plant away from others for some time and regularly inspect it for any infestation.
If you visit another grow room, change your clothes and shower before entering your grow room.
Collect dead leaves and other plant matter from the growing space regularly.
Ensure all visitors are clean.
Sanitize all the tools between uses.
Don’t allow pets into the grow room.
Ensure there is great airflow in the room.
Sprinkle diatomaceous earth on your soil regularly.

6) Outdoor Prevention

Check for any spider mite eggs or spider mites on new weed plants using a handheld microscope.
Dip the plants in a mixture of room temperature water and Mighty Wash or Safer Soap. Alternatively, spray it with an effective pesticide.
Keep the plants isolated for some time.
Ensure you are clean before going to where you have your weed plants, especially if you visited another cannabis grower.
Do not kill insects in your gardens like ladybugs or Western Predatory Mites because they will help you by eating the spider mite. Therefore, when spraying, use a pesticide that is specific to spider mites instead of a broad spectrum.
Have a good ground cover to prevent the spider mites from surviving in your soil. You could sprinkle diatomaceous earth or have weed barrier fabrics.
Ensure the place you have your plants receives a lot of wind and cool air.