Cannabis growers face several challenges, and fungus gnats are one of the most common and frustrating of these. These tiny black flies reproduce quickly and repeatedly, and if you don’t stop them early on they can cause a great deal of trouble. Whether you’re growing inside or outside these bugs can be a problem, but either way treating an infestation is relatively simple and cost-effective. There are plenty of commercial and DIY ways to get these bugs under control.
In this guide, we’ll explain what these bugs look like and how to identify them. We’ll also show how to get rid of them with various natural and man-made means, and we’ll tell you how to keep them out of your cannabis garden after they’ve been eliminated.
What is a Fungus Gnat?
As mentioned above, fungus gnats are small mosquito-like flies. They look much like fruit flies, but they’re easily distinguishable under a microscope. These common garden pests have a never-ending life cycle that goes like this:
To defeat fungus gnats in a cannabis garden, it’s best to catch them as early as possible. Especially after buying your own pot seeds online, you’ll want to stay ahead of the game, so you don’t waste your time having to re-germinate a whole new crop from scratch.
Detecting Fungus Gnats on Marijuana Plants
Before taking steps to manage an infestation, growers must first learn to identify the signs of a fungus gnat infestation. It’s necessary to distinguish these gnats from common fruit flies, as eradication requires two separate approaches.
As soon as an infestation is detected, decisive action is crucial. One of the best ways to confirm the problem is with sticky cards, which are available at all garden centers. Choose yellow cards to attract more gnats. Put the cards in the soil with the plants and leave them for a few days. If there are bugs stuck to the cards after that time, there’s a problem.
Another easy way to detect an infestation is to cut a potato and stick the cut end into the soil. If the cutting is full of maggots after several hours, you likely have a fungus gnat infestation on your hands.
How Do Fungus Gnats Harm Cannabis Plants?
Although we touched on it briefly above, fungus gnats do most of their damage in and under the soil. Fungus gnat larvae feed on plant’s roots and cause irreversible damage in severe cases. The damage leads to stunted growth and yellowing of foliage due to the plant’s inability to absorb water and nutrients. As the damage gets worse, the plants may die unless corrective actions are taken. Read on to learn how these gnats end up becoming introduced into a grow room or greenhouse.
Why and How Do Fungus Gnats Get Into the Grow Room or Outdoor Garden?
There are many reasons why you may see these gnats crawling in the soil or flying around your plants. Most of these reasons come down to simple human error, but in some instances fungus gnats may be brought in by larger animals or new plants.
Ventilation systems bring in clean, fresh air and get rid of hot, stagnant air. If the system isn’t fully sealed, though, it may actually allow fungus gnats an entry point into your grow. Prevent these issues with a HEPA filter on the intake that stops bugs from entering.
Ways to Eliminate Fungus Gnats
If you’ve taken precautionary steps to keep fungus gnats out of the garden, they’re less likely to present a problem. However, even the most organized grow rooms may encounter issues with pests. Here are several ways to get rid of fungus gnats once you’ve established that they are present.
Now that we’ve discussed some of the most common natural and organic gnat treatments, we’ll show you a few more DIY remedies for more serious infestations.
Fungus Gnat Home Remedies
If there’s already a problem and you don’t have any commercial pesticides, there are a few do-it-yourself remedies to consider. Here are a few treatments commonly used by experienced cannabis cultivators.
With these home remedies, you’ll find it easier to get fungus gnats under control and ensure the health of the crop.
Be Careful With Compost Piles
Compost piles are healthy and beneficial for plants, but gnats love them too. Carefully examine the compost before feeding plants. To prevent the pile from attracting insects, remove excess moisture. Compost shouldn’t feel excessively moist; rather, it should feel like a nearly dry sponge. If there are bugs in the pile, sprinkle it with diatomaceous earth or any of the above home treatments.
After treating the entire compost pile, add a little moisture to activate the treatment and kill larvae and gnats. Once the pile has dried again, cover it with plastic. Stir it up frequently and allow plenty of time for it to dry.
A Few Final Thoughts on Fungus Gnats in the Garden
It’s crucial to follow a regular checklist to look for signs of disease and pest infestation in the garden. When these problems are detected early on, most of them can be eliminated. With the tips and tricks in this guide, you’ll have a healthier and more bountiful cannabis crop. Buying cannabis seeds is very simple these days, but caring for them properly is what ensures you get the best possible buds to enjoy at the end of your efforts.