If you have grown cannabis outside, there’s a good chance you have experienced bugs on your plants. However, if you’ve only grown indoors it’s just as important to be familiar with common pests as they can make their way inside your home. It’s also beneficial to know which bugs are harmful to your plant, and which ones can actually help your plants. This will help you determine whether it’s time to take action against the insects or not.
How do pests actually get inside your home?
There are several ways these bugs can travel indoors. First, on your clothing. This is an easy way for them to take a trip into your home. We recommend changing your clothing before going to check on your cannabis plants as this will prevent unwanted visitors.
Another way they get inside is on your pets. If your pet goes and plays in the garden, there’s a good chance they may bring insects back into your home. To avoid unwanted friends coming inside on your pet, you can give them a quick brush and inspect for unwanted critters.
You may be surprised to find out that only a fraction of the bugs found in your garden are harmful to your plants. Many of them are actually quite beneficial and will help you plants thrive. This is why it’s important to know what bugs are good and which ones are bad, so you don't destroy the good ones.
So.. what makes an insect a beneficial insect?
Many of these bugs fall into 2 categories:
- Pollinators: These bugs are generally not welcomed in gardens that include cannabis plants, as most people don’t want their cannabis plant pollinated. When a cannabis plant gets pollinated it will develop seeds, which is generally undesired. However, in a garden without cannabis plants, these bugs are welcomed as they help pollinate the plants.
- Predators: These pests consume the bad insects in your garden or growing space. These bugs are extremely helpful in any grow space as they keep the bad bug populations low.
So, let's get into some of the different types of beneficial insects!
Lady bugs are excellent plant friends, and are considered a predator to many species of insects. They consume several species of the bad bugs such as whiteflies and aphids. Did you know a single lady bug can eat up to 40 aphids per hour? Some growers actually order lady bugs online and release them into their home to prevent infestations of the bad bugs.
While not all nematodes are beneficial to your plants, there are some that consume the bad pests, which can be very helpful for preventing infestations. These insects can come in many different shapes and sizes. Most species are microscopic, meaning you won't see them without a microscope.
Some of the parasitic worm varieties of nematodes will kill over 200 types of insects that mature in the soil such as fungus gnats, fleas, and Japanese beetles. This is another type of insect growers will purchase and invite into their home to keep pests at bay. Often sellers will combine several different species of beneficial nematode into one package as different species will consume different prey. In the package linked above, the company has included the species Heterohabditis bacteriophora, Steinernema carpocapsae, and Steinernema feltiae. These beneficial nematodes will consume a long list of pests.
This bug is commonly seen as a scary pest, but they’re actually a friend to your plants. They will attack and kill almost any species of pest in your garden or home including flies, moths and beetles. However, they are also known for turning on each other and consuming each other and other beneficial insects, so they are less commonly invited into a growers home to keep pest populations down.
The mature Green Lacewing consumes pollen and nectar of nearby plants, but the larvae feed on harmful insects such as aphids and caterpillars.
Spiders are an arachnid, not a true insect but they are definitely beneficial to your plants. They are attracted to prey that move, so they will consume almost any type of insect found on your plants including aphids, mealy bugs, thrips and more. So no, you shouldn’t kill a spider in your home, as it's keeping many other insects out!
It’s important to note that not all beetles are beneficial to your garden, but most species of ground beetles are beneficial. In both their larvae and mature form, they consume pests such as thrips, slugs, caterpillars, and silverfish.
These are pests that will harm your plants. Most often these are pests that feed on the leaves or roots of your plant, causing damage. It’s important to become familiar with these pests so if you see them on your cannabis plants you know it’s time to take action.
Thrips are terribly hard to get rid of once the infestation is established. These bugs pierce the leaves and suck the juices out of the leaf, leaving behind brown or silvery markings. You may also notice dark purple/ black spots on the leaves, this is thrips excrement. The worst part about these bugs is that they lay their eggs inside the cells of the leaves, so beneficial insects cannot eat the eggs, and insecticidal sprays will not damage the eggs either. Beyond that, the eggs can lay dormant for months, and the infestation can reappear months later. It is best to take action the minute you see signs of thrips in your home or garden. Some growers will kill the infected plant to prevent further spread.
This is a close up of what a heavy infestation would look like:
However, most of the time you would notice an infestation before it gets this extreme, and without a high quality microscope or zoom lens you would not be able to see them this well. This image below is more accurate to what you would see on your plant.
These pests are less common on cannabis plants, but they will infest one if that is their only choice. These bugs often look like chunks of cotton on the plant, most commonly in small crevices between the leaves and stem. Some growers describe them as “hairy” looking, as they have many legs that often get mistaken for hairs. This pest slowly sucks the juices out of the leaves, so they are not a major threat as they rarely kill a plant. However, we recommend taking action as soon as you see them to decrease the spread.
This is another pest that isn't a serious threat to your cannabis plant, but are still considered a pest as they can cause mild damage if their population becomes large enough. Fungus gnats live in your plants growing media, and feed on the fungus in the soil, and occasionally the plants roots. On a plant with such an expansive root system such as cannabis plants they rarely cause noticeable damage, it’s only succulents that they actually cause damage to as they have such delicate roots. Fungus gnats look almost the same as fruit flies, and you can often see them fly away if you disturb the top of the soil.
Aphids are a common pest to cannabis plants both indoors and outdoors. They can also cause serious damage so it’s important to start treatment as soon as you notice them. Aphids suck the juices out of the plants leaves, leaving holes and dried up splotches over the leaves. They come in a variety of colors, but most often they are green or black. They are often found on the undersides of the leaves or clustered on the stem.
Green Aphids on the stem of a plant
This pest is technically an arachnid not an insect, but they are important to note here. Spider mites can cause severe damage to a plant very fast. They puncture the leafs surface and suck the juices out, causing tiny dead splotches over the leaves. They look like tiny white mites and webbing is also common to see on the leaves. If you look closely you can actually see them moving around. This is more common indoors as they prefer dry conditions.
In the image below, notice the tiny webs and dots on the leaves. This is what a spider mite infestation looks like. The leaves are also dull in color, this is because the spider mites have sucked a lot of the liquid out of the leaf.
Caterpillars come from many species, but in general they are bad as they feed on the foliage of your plant until they pupate and become moths or butterflies. Depending on where you live, you may have Gypsy moth caterpillars taking over your garden too. This species is invasive to North America, and is commonly found in the Northern United States and Southern Canada. As they have no predators that consume them, they can quickly take over your garden and eat all the leaves off your cannabis plant. We recommend becoming familiar with the types of caterpillars in your local area so you know whether to move it to a different location, or start using an insecticide to control the population.
Bugs can be a major stressor for some growers, especially those who are not familiar with the different species. If you dont want to deal with pests, you should consider a Grobo. Grobo is an automated hydroponic grow box designed to make growing easy. Since it has a door that is airtight, bugs cannot enter the Grobo unless you open the door. This keeps the plant fully protected from any sort of pest.
The Grobo has several other smart features that will make growing plants stress-free. Grobo automatically adjusts the pH of the water and automatically doses nutrients so your plant never goes hungry. The lights also change spectrum depending on the stage of growth your plant is in so it always has the perfect amount of light. With thousands of seed recipes in our app, we are sure you will find exactly what you want to grow!
Have you ever dealt with pests on your plants? Let us know in the comments below!