Spider mites are all too common a problem for cannabis growers. Whether you’re growing cannabis indoors or outdoors, you’re more likely to find spider mites in your crop than any other type of pest. They’re microscopic. They’re arachnids. They will suck the life out of your beautiful plants.
Spider mites are only about 4mm in size (0.04 inch). Their size makes them difficult to identify, as they will look less like spiders than tiny freckles on your plants’ leaves. You will likely find them on the underside of your cannabis plants’ leaves. If your plants’ green leaves are covered in a sea of yellow or white dots, chances are you’ve got spider mites. If more than half of a leaf is covered in this spotted pattern, remove the leaf, destroy it, or at least discard it far from where your plants are growing.
While the best way to keep spider mites from messing with your crop is prevention, if these tiny pests take hold of your plants, there are a few things you can do to send them to microscopic-arachnid hell.
You can make natural repellents with garlic, citrus oil, hot pepper, and liquid seaweed, which you can mix in spray bottles and apply to your plants. This should help repel spider mites, and prevent an infestation from spiraling out of control. If this doesn’t work after the fourth or fifth time spraying down your plant, move on to something more heavy duty (see below).
While your plants are still small, try dipping them in pyrethrin, a natural insecticide made from the Pyrethrum Daisy, also known a Chrysanthemum. This will help ward off spider mite attacks. This is a stronger alternative to the above, homemade spray solutions.
In our opinion, pyrethrin, the natural insecticide mentioned above, is your best bet. But you can also try spraying neem oil, horticultural oil, cinnamaldehyde, or nicotine sulfate on your plant to ward off spider mites. Apply these solutions every five to ten days. Two or three applications should successfully control spider mites. Switching the type of insecticide and/or repellent you’re using will prevent the mites from adapting and growing immune to these pest-control methods.
Spread a non-toxic pest control product (like Tanglefoot) around the base of your plant’s stems. Do the same around the rim of your plants’ containers. The idea here is to create a sort of moat, preventing any more pests from being able to access your plants.
Introduce predatory insects. The two most commonly used predatory insects are Neoseiulu californicus, and Mesoseiulus longpipes. If you google “spider mite predators” followed by your town or city name, you should easily find a nearby place that sells these predatory insects. You should put about 20 predatory insects on each plant to control spider mites. Introduce a new batch of predatory insects every month.Just make sure that before you release these predatory insects, you’ve cleaned off any previously applied insecticides. You can do this by rinsing your plant with a spray bottle of water. Caution: if the spider mite infestation is already too big, predatory insects may not be able to control the problem.
Keep it somewhat cool in your growing room during an infestation. The cooler it is in your growing room, the more slowly these mites will reproduce. If you can get the temperature below 20°C (68°F) without hurting your plants, this is ideal.
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