Spider Mites on Cannabis | How to Prevent and Eliminate?


Let’s face it; growing cannabis in an indoor grow room is not an easy task. You need to regulate the temperature, light, and ventilation to get those perfect buds at the end. However, like any other plant, cannabis plants can become infested by pests as well. 

Can you imagine tending to your cannabis crops all day in your grow room just to find some creepy crawlies feasting on them? There are many pests you should look out for as a marijuana grower, but spider mites cannabis are the worst.

spider mites cannabis

Not only do these mites invade your buds, but they also breed quickly, which can lead to the ultimate destruction of your crop. Don’t worry just yet; these spider mites are pesky but not unstoppable. 

We’ve compiled everything you need to know about spider mites cannabis, their prevention, and elimination in this article, to help you keep your cannabis plants healthy. So let’s get started. 

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What Are Spider Mites?

To fight spider mites cannabis, you’ll need some necessary information about them. They’re deceptively tiny pests, measuring less than a millimeter. To the naked eye, these predatory mites look like orange or red specs, and might even go unnoticed. 

These mites have tiny, razor-like mouths which they pierce into healthy plant cells by implanting on plant leaves. After that, they suck the nutrients out of the leaves to sustain themselves. Their infestation forms yellow or orange spots on the leaf surfaces, which most growers mistake for nutrient deficiency. 

Another factor that makes spider mites almost lethal for marijuana plants is their high reproductive rate. These mites reach their sexual maturity threshold after only four to five days of hatching. After that, they begin reproducing again until the mite population gets out of control. 

Besides that, their new eggs hatch in only three days. Also, a single female mite can lay millions of mite eggs at a time, so if you’re late in spotting these on your cannabis plant, you’re most likely doomed. 

You see, these mites feed on chlorophyll, which is essentially the primary food source for your plant. Now, imagine millions of spider mites on cannabis sucking all the nutrients away. It’s highly unlikely for a plant to survive such infestation if it’s not tackled in time. 

Wait, there’s more. You can’t kill these mites off in one go. These pesky pests have a hell of an immune system. This means they can adapt to the killing method you use against them, so you’ll have to be consistent and precise with your destruction methods to achieve the desired results. 

In order to tackle a mite infestation, you’ll need to identify them first. 

What Do Spider Mites Look Like?

Spider mites are minuscule. That’s why they’re difficult to spot or identify. There are several types of spider mites, namely, russet mites spotted spider mites and broad mites. Broad mites, the Polyphagotarsonemus Latus, are the most abundantly found spider mites in cannabis plants. 

To identify these tiny insects correctly, you’ll have to use a magnifying glass, as they’re not usually apparent to the naked eye. However, if there’s a large infestation in your marijuana plants, you’ll be able to spot them with your bare eyes as well. 

Different species of mites differ in their body color, but the shape and structure of their bodies are more or less the same. They have tiny, dew-drop shaped bodies that may be transparent or slightly yellow in color. 

Furthermore, you can also identify them by their small legs. Spider mites cannabis have a total of three pairs of minuscule legs. The first pair is located at the front, another on their thorax, and a couple of wispy legs at the back. In males, the last pair of legs are slightly more pronounced. 

Even if you recognize their appearance, the fact remains that they’re barely apparent through your naked eye. Don’t worry; we’ve got some ways you can pick out an infestation if there’s one in your marijuana plants. 

Early Signs of Spider Mites

Even if you don’t spot spider mites with your naked eye, you can easily see the signs of their presence if you’re a vigilant grower. At first, the mites may appear as small black dots or specs on your leaves. 

As the infestation progresses, you may see evident yellow to orange spots on your leaves, showing that they’re being drained out of chlorophyll. 

The worst part about a spider mite infestation is that if you’re late in spotting them by a day or two, they’ll completely devour some parts of your cannabis plants. The trick is to be vigilant and conduct rigorous checks every other day. 

Besides that, spider mites also cover their plant territory with a silk-like overcoat. You can easily spot the covering due to dust and dirt accumulation. Also, if you’re faced with mite infestations before, it’s likely that the mites are in hiding and will return again soon. 

How to Prevent Spider Mites on Cannabis?

Once you’ve been infested by spider mites, the probability of them returning to attack your plants again is higher every time. That’s why it’s better to take precautions against them and stop the first infestation in its tracks. 

Here are some preventive measures you can take for spider mites cannabis. 

Keep Other Plants Out of Your Grow Room

Outside plants are more likely to be infested by insects. That’s why you should never bring other plants inside your grow room, as this will make your grow room plants prone to infestation as well. 

keep plants out of grow room

However, you need to bring in a weed plant from outside, keep it isolated for a week or two. Check the plant thoroughly with a magnifying glass before you take it inside. 

Keep Your Grow Room Clean

Always remember to declutter your grow room. Make sure there are no dead leaves lying around in the soil. Besides that, if you’re coming from outside, wash your hands before entering the grow room. Also, don’t let your pets inside as they can create a mess and form a breeding place for pets. 

Always Keep Checking

Even if you don’t think your cannabis plants can become subject to spider mites, you should keep checking regularly. That’s because these mites are sneaky and grow rapidly, so it’s better to have a heads up before the situation gets out of hand. 

Keep Beneficial Insects

Whatever you do, don’t use pesticides to kill spider mites in your marijuana plants. Why? You see, pesticides kill away all the insects, even the ones that are beneficial for your plants. Insects such as ladybugs and other predatory mites exist in organic compost. They prey on spider mites and help protect your plants. 

How Do I Kill Spider Mites on Weed Plants?

If you’ve done everything to prevent the sneaky mites, but they still made their way to your plants, you can still control them. Here are some ways to kill and control the population of spider mites. 

  • You can increase the humidity in your grow room to get rid of mites. Spider mites thrive best in a dry environment, and a sudden increase in moisture will decrease the growth of their population.
  • Insecticidal soap is also effective against spider mites. It will not completely eliminate the population but will lower the damage to your cannabis plants. 
  • Pyrethrum can kill off spider mites immediately, but mites get used to it and grow immune over time. 
  • Besides that, you can use homemade herbal pesticides to target spider mites. These include cinnamon and clove tea spray and neem oil spray. If you’ve spotted the mites in their initial stage, you can even get rid of them by using a hard water spray. 

Homemade Spider Mite Spray for Cannabis Plants

Insecticides are effective at killing off spider mites, but as we mentioned before, they can harm the natural growth environment and kill off beneficial bugs as well. Also, substances like abamectin and lindane, used in commercial insecticides and harm humans as well. 

Here are some excellent spider mite killing sprays that you can make at home. 

neem spray

Bleach Spray

To avoid spider mite infestation, you can use a bleach solution in your grow room to prevent their population growth. Just add a tablespoon of bleach into a gallon of PH balanced water. Spray the solution all over your grow room. 

Alcohol Spray 

Another effective way to kill off spider mites is to use a homemade alcoholic solution. Mix one part of alcohol into nine parts of alcohol and spray it over your plants. This spray will not inflict any harm to your plants and will kill off the mites completely. 

Neem Spray

Neem oil is a great solution for all types of bugs, including spider mites. Although it has a pungent smell that can cause breathing difficulty in humans, it can be used safely when diluted. 

Final Words

That wraps up our guide for spider mites cannabis. Spider mites are harmful, sneaky pests that can destroy your crops in a matter of days. The best solution is to prevent their infestation by creating a humid environment in your grow room and keeping it clean at all times. 

However, if an infestation does occur in your cannabis plants, the first thing you should do is stop their reproduction. You can do this by regulating the temperature and using water sprays. In the end, in case of a difficult situation, go for commercial sprays or invasive homemade sprays to control the mites. 

Remember, mites are good at hiding. You’ll think that they’re gone for good, but in fact, they disappear for some time only to attack again. So even after you’ve killed off all the mites, keep checking your leaving thoroughly every day. 

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