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Troubleshooting Common Cannabis Pests

Any cannabis grower can attest to the fact that once you’ve invested all that time and effort into tending your plants, you start to get a little attached to them. They’re like your pets! Which is exactly why it’s that much more stressful when invasive pests show up uninvited and threaten the health of your plants. They aren’t always easy to spot at first, but there are some telltale signs of pest invasion to look out for. If you spot pests early, they’re much simpler to get rid of. Here’s a list of the most common cannabis pests to look out for, how to check for early signs of infestation, and the best way to get them out fast.


These are one of the most common and troublesome plant pests around, because they reproduce ridiculously quickly without needing to mate. They feed off your plants by sucking out the sap, leaving behind a sticky layer of honeydew that can attract other varieties of unwanted pests, or even promote mould growth.

How to Spot Them:

These tiny bugs can be black, red, white, or green (the green variety being the hardest to spot since they blend right in with the leaves) but you’ll typically find them setting up camp on stems or the underside of the leaves away from direct light. If you notice sticky residue on your plants, or if the leaves begin to turn yellow and curl under, take a look under the leaves. If your vision isn’t super sharp, use a magnifying glass to make it a little easier on your eyes.

Getting Rid of Aphids

If these pesky sapsuckers have started to wreak havoc on your precious plants, act fast! Leaves with significant damage should be pruned and disposed of immediately. Next, you’ll want to make an insecticidal soap solution using water and castile soap and shake it up in a spray bottle. Spritz generously over your plants, monitor them over the next few days, and then apply again if there are still some traces of aphids. Make sure you use natural soap, not dish detergent!

Spider Mites

Similarly to aphids, these bugs suck out the sap from your plants. However, they’re even smaller and trickier to see, so you really have to watch closely for these guys. They reproduce really fast, too””one single mite can produce over a million babies in one month. Yikes!

How to Spot Them:

Check the underside of your leaves regularly for tiny little speckles. These could be the mites themselves or the little white eggs they lay. Leaves will start to yellow and die off rather quickly if they’ve been attacked by spider mites. If the infestation is particularly bad, you’ll notice a white threadlike webbing starting to appear between leaves, hence their name.

Getting Rid of Spider Mites

You’ll want to take an aggressive approach to eradicate spider mites. They’re pretty sneaky, so often if you think you’ve got them dealt with, there’s a whole colony of tiny young ones waiting for the right time to overthrow your precious plant. They also tend to build up a resistance to insecticides if you use the same one repeatedly, so it’s worth it to cycle through different methods so they don’t get stronger. We recommend insecticidal soap sprays, neem oil (an insecticidal compound extracted from the neem tree), or a couple of shots of vodka mixed with water in a spray bottle. Spray the vodka solution not just on the plants, but around the whole growing area just to be extra certain there aren’t any more hiding in there.   

Fungus Gnats

These little winged bugs don’t actually eat your cannabis plants, but they do a number on plant roots, and they can mess with soil quality which will make your plants much more susceptible to fungus and disease.

How to Spot Them:

You’ll see fully grown fungus gnats buzzing around the soil since they’re a bit more visible to the naked eye than many other bugs. If your pots have drainage holes, you may see their larva floating around in your drip tray (blegh, gross).

Getting Rid of Fungus Gnats

They like to lay their eggs in moist soil, so as far as prevention goes, keeping the top layer of soil dry and laying down some cloth over top will make it harder for them to go about their business. Keep your windows closed too because this is an open invitation for them to show up. If you find fungus gnats on your cannabis plants, mix up 1 part 3% hydrogen peroxide, and 3 parts water. Water the soil with this solution and those fungus gnats won’t stand a chance.

A swarm of invasive insects won’t be a death sentence for your cannabis plants as long as you deal with them as soon as possible. As they say, an ounce of prevention is worth a pound of cure (that’s a mathematical analogy any cannabis producer can understand!) so keep a close watch on your plant leaves, checking them regularly for creepy crawlies, speckles, sticky residue, or any suspicious changes in colour.


Read through our Growing Guides for tips to enrich your garden! 

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