Preventing Spider Mites on Cannabis Plants

A major pest for any marijuana grower is the spider mite. These tiny arachnids infest many types of plants, including cannabis, living on the underside of the leaves. They use their mouthparts to draw out sap and nutrients from the marijuana plant. They lay many eggs and their numbers grow quickly, so they can do plenty of damage over time. Leaves will become mottled and brown, and might eventually be scorched. Fine webs will be seen when there is a significant infestation, hence their name.

While spider mites are a problem throughout agriculture, they pose specific difficulties for growing cannabis. The quality of the plant is highly important, and damage done to marijuana plants by spider mites can be unacceptable. And when there are spider mites on cannabis in flowering stages, they require delicate handling and many spider mite killing methods cannot be used.


If your cannabis is in a vegetative state or in the very early phases of flowering, there are a number of useful methods for eliminating the mites. The simplest is to spray them off with water, making sure that you’re hitting the underside of the leaves. This will remove many of the mites in your weed, although it’s not 100% effective. This is best if you’ve caught an infestation in the early stages. However, if you’re already infested, you should look into a spider mite spray, such as our non-toxic LavaMite™.

Please read our article on preventing spider mites for detailed prevention methods.


Most common spider mite species prefer dry conditions; so turning up the humidity will strongly discourage their presence. This has the advantage of not being labor intensive, and completely affecting all areas without any missed spots. When your cannabis is in a vegetative state, you can turn up the humidity fairly high without having any problems – it can easily go up to 70%. The main issue is to turn the humidity down when they enter the flowering stage. Since the buds are already moist, excessive humidity will create the risk of mold infections. This is another reason why it’s best to check for spider mites early on, and eliminate any before you reach the flowering stage. High humidity is a very convenient method of keeping the mites away.


You can also spray mixtures of soap, water, lemon juice, garlic extract, cinnamon, clove oil, and so on. These ingredients are claimed to be effective at destroying spider mites, eggs, and webbing. One side effect is that too much of one ingredient can harm the plant. You should always be sure to wash off the leaves about 15-20 minutes after treatment, so that it doesn’t cause any leaf burn. Also, you should water the cannabis plants beforehand, so that they will be less receptive to absorbing the solution. This is an effective solution for the vegetative state, but you shouldn’t treat flowering plants this way.

If you need an even stronger treatment, there are sprays, such as LavaMite™ which deal specifically with this issue. Our product is great at killing spider mites on weed plants, although you have to use it properly so that there aren’t any survivors.

Overall, spraying with LavaMite™ is the most decisive solution for a spider mite infestation on your weed crops.