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Bugs, Mold & Mildew

While mold and mildew generally appear due to environmental issues, harmful bugs will always be a threat, especially for outdoor growers, as any bug can appear at any time throughout the entire plant's life cycle.

Organic Pest Control Options

When it comes to spraying your plants, all-natural pesticides are the way to go as it is generally safer than the synthetic options, some of which can even be used on the buds up to the day of harvest.

Insecticidal Soap is the first go-to method due to its simple ingredients that anyone can make from home with a 1 tablespoon of pure soap to 1 quart of water mix, and is somewhat effective at controlling multiple types of pests.

Neem Oil is another popular pest control method that is made from the seeds of a neem tree. Typically made with 1% neem oil mixed with 99% water, this naturally occurring pesticide is effective against multiple types of pests, but due to its oily residue, it should not be applied in direct sunlight or on the buds.

Azadirachtin products such as AzaMax extracts the main pest control ingredient from neem oil to makes a naturally occurring pesticide without the oily residue. Similar to neem oil in effect, this can be applied on the buds, making it a viable choice for the entire life cycle of a plant.

Spinosad is a natural insecticide derived from a species of bacteria that affect the nervous system of multiple types of pests it comes in contact with. One of the few pesticides that can be used for caterpillar control, spinosad unfortunately also affects bees while it is still wet, so if used outdoors, be sure to apply at night to avoid unwanted casualties.

Bacillus Thuringiensis (BT) is a naturally occurring bacteria with different strains that can specifically target certain pests. Most commonly used to control caterpillars, there is also a strain of BT that can be used in the soil to control fungus gnat larvae.

Mold and Mildew

What happens when you couple high humidity with low air movement?


White powdery mildew is pretty easy to identify, as it looks like white or yellow flour-looking patches on your plant that rub off easily. While it usually shows up first on the leaves, it can migrate fast onto the stems and buds.

To fix a powdery mildew problem, you first want to remove any leaves that are completely covered in it. From there, for the leaves that might have a few spots of powdery mildew, you can salvage them by wiping off the powdery mildew with a damp paper towel and then spray down the entire plant with a milk mix (one-part milk to every two parts water) or neem oil, which will help prevent the powdery mildew from coming back.

White Powdery Mildew

For bud rot, this mold can be a lot harder to detect because it typically starts to develop inside dense buds where moisture can get trapped. If found early, it will look white and fluffy, but typically, by the time it is discovered, it is due to parts of the buds dying and turning dark brown and gray, and falling apart to the touch.

There is no cure for bud rot; if discovered, you will need to remove any parts of the plant that are already affected and then choose to either harvest the rest of the plant early or change the environment in your grow space by adding more air circulation, lowering the humidity, and removing excess foliage to minimize the chances of the bud rot from spreading.

Tiny Bugs

There are tiny bugs that like to eat the cells of the leaves: spider mites, aphids, thrips, and whiteflies all fall in this category. If you notice tiny white specks on the leaves or little dots moving around on the underside of the leaves and small tiny flies flying around, then you most likely have one of these. All these can destroy a plant if left to colonize, and the scariest of the bunch are spider mites because, on top of damaging the plant, if left alone for a short period of time, they will also cover everything with webbing, ruining your harvest even if you manage to get rid of them.


Both insecticidal soaps and neem oil can be used on the leaves and stems to control all these tiny bugs, and if you are in the flowering stage, azadirachtin and spinosad are both safe to be used on the buds as well.


Now, if you have little white dots crawling in your soil and tiny black bugs flying around with no visible damage to the leaves, then you have fungus gnats. These little buggers, while not as detrimental as the previous microscopic bugs we just covered, love wet soil and will lay their eggs in it to feed on the roots of your plant. So, while a few gnats here and there are not very noticeable, a full infestation could stunt the growth of your plants.

Since these bugs multiply in wet soil, the first step to removing them is to keep the topsoil dry by watering after longer intervals and adding a top layer of fast-drying material to the plant like perlite. A treatment of neem oil or BT (be sure to use the one that targets gnat larvae) to the top layer of the soil will also help as well, and neither will affect the plants negatively when used on the soil.

Sucking Bugs

Now, onto slightly larger insects, there are mealybugs and scales. Both of these like to suck the sap out of the plants and can be found feeding not only on the leaves but on the stems as well.


Since both are visible to the eye without magnification, you can first try to pick, wipe, or spray off any you see with water and then use either neem oil, azadirachtin, insecticidal soap, spinosad, or a combination of these to get rid of the rest, as they are all effective in eliminating these pests.


Jumping Bugs

Crickets, grasshoppers, locusts, and leafhoppers are all easily identifiable due to their large size and large legs. While the first three will eat chunks of leaves at a time, leafhoppers suck out sap from the leaves, leaving clusters of brown dots.


These are all easily identifiable due to their size, and if you can shoo them away from your grow space, that is the easiest way to get rid of them. To prevent them from coming back, neem oil, azadirachtin, insecticidal soap, and spinosad all work for these bugs as well.


Crawling Bugs

Now we have the crawlers: slugs, snails, and caterpillars. Other than green caterpillars, which can easily blend in, these should all be pretty simple to spot, and they have the same eating habits: chewing through chunks of leaves at a time, and worst, eating through the buds.

Slugs and snails are easier to deal with because they need to crawl to a plant to access it, so an easy fix is to first remove them from your plants by hand and then tape a layer of copper foil tape around your pots. Slugs and snails get an electric shock when touching copper, so it creates a natural barrier to block them out. For caterpillars, you will need to use spinosad or bacillus thuringiensis (BT).

Spider Mite


Fungus Gnat

Mealy Bugs


Beneficial Bugs

Also remember that not all bugs are bad for your plants. There are a large number of beneficial bugs that will protect your garden from the plant eating bugs we just covered. The two most beneficial bugs you can have in your garden are ladybugs and lacewings. While one is much cuter than the other, both will eat up all of the smaller bugs listed above and are the most natural way you can control the pest population. Both of these are also sold live by the hundreds at most gardening stores and online, however they are not a permanent solution; if there is no detrimental pests in your grow space or once the pest infestation is over these bugs will leave your grow area in search of more food. Spiders will also serve this purpose, however you definitely don't want too many of these hanging around unless you like running into webs.

Did this guide help? This article was taken directly from The Absolute Beginner's Guide to Growing Cannabis book, so if you like the advice above you'll love the rest of the book, which includes a lot of exclusive content not found anywhere else. You can find both the e-book and paperback copy on Amazon, and it's free with a Kindle Unlimited subscription!

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