Cannabis is an attractive plant for pests, especially when grown in soil. Pests can be anything from insects to different kinds of mold. If not taken care of quickly it can lead to more extreme problems eventually leading up to crop loss.

Paying attention to your cannabis leaves can help you spot any problems quickly. In fact, most cannabis problems usually start in the fan leaves coincidentally. Seeing white spots on your cannabis leaves can mean a few things.

White spots on your cannabis leaves are usually a sign of something going on with the plant. You should check underneath the leaves for eggs or moving insects. If the spots are shiny it could be thrips but if there are webs between your fan leaves it could be mites.

Let’s have a closer look at some of the pests that can cause white spots on your fan leaves and ways you can prevent it from happening with your cannabis plant.

What Causes White Spots On Cannabis Leaves?

There can be a serious pest problem before you know it. That’s why you need to act quickly when you suspect something is wrong. Here are some of the common causes of white spots on your cannabis leaves.


Thrips are insects that look different depending on where you are and how old they are. They can appear as little white worms or insects with wings. They love to stick their faces into cannabis leaves and suck out all of the liquid.

This damage is often what causes the silvery-white spots on the fan leaves.

Neem oil or diatomaceous earth is a great remedy for thrips and they aren’t really a tough pest to get rid of.

Spider Mites

Spider Mites are more of a serious problem in that once you have them, they spread quickly and can destroy your whole crop pretty easily. They will often appear as white spots on your fan leaves.

Once you see that you should check the underside of the leaves to see if there are eggs there. If you see spider webs between fan leaves or flowers then you might be in trouble. Neem oil and hard water spray have been known to be effective against spider mites.

Powdery Mildew

This is a fungus that loves to feed off cannabis fan leaves. It has a distinct white fuzz that spreads until it covers the entire plant. Powdery mildly starts as white fuzz spots in the beginning stages of its infestation.

Fixing your grow room climate and using milk or sodium bicarbonate are great ways to combat powdery mildew.

How To Prevent White Spots On Your Cannabis Leaves

Preventing these issues is easier than dealing with them once they happen. For pest control ensure that you aren’t bringing any clones or plants that have bugs on them. Be sure to do a thorough inspection of all incoming plants and take care of any problems before they come into your garden.

For powdery mildew and mold be sure to keep your space climate as consistent as possible. A lot of these problems take hold when there is a spike in humidity or there is a lack of airflow between the plants.

As long as you pay attention to what your plant is telling you and keep a clean growing space you shouldn’t have any problems with pests or mildew.

Leave A Reply