Critters, especially the minuscule ones, seem to have an affinity for the human face. Fungus gnats are no different.
Gnats are tiny black insects that fly around plants. The adult gnats lay their eggs on damp soil, which then also becomes their source of food.
Aha! So we know what causes gnats — damp soil.
Prevention is better than cure
Indoor plants get less sunlight than outdoor plants. Hence, the soil stays damp for longer. One of the main causes for fungus gnats is zealous plant owners overwatering their plants.
Gnats also love organic matter in the soil, like rotting leaves. So if you compost your kitchen waste, try to keep that unit away from your garden. Also, clean up the leaves that fall from the plant.
Avoid doing these two things and you can easily prevent a gnat infestation. But if you do get gnats, don’t panic. Gnats aren’t the worst that can happen to your plants. They are relatively harmless. But your priority should be to deal with a gnat infestation before it gets out of hand.
For this, nothing beats preventive plant care. We’ve observed that plant lovers prefer not having to deal with plant diseases and infections, over letting their plants rot, and then having to discard or replace them. Somewhat obvious, but still most people call us only after their indoor plants are gnat-infested.
Sure, we know how to deal with these problems, though we still recommend preventive care.
8 Ways to get rid of gnats
Natural methods
Whenever you’re dealing with organic matter like plants, natural is best. Here’s how to get rid of gnats in plants naturally.
Chemical methods
Chances are slim that you’ll have to resort to chemical methods for gnats. But if you don’t take immediate action, then gnats can multiply faster than bunnies.
- Trap them with Vinegar
Fill up a dish with vinegar and fruit juice. The gnats will be attracted to the smell of the juice and land in the dish. Unfortunately for them, they will drown in this mixture.
There's another version of this trap. Mix one tablespoon of sugar, 3 drops of dish soap, and one cup of white vinegar in a bowl. Cover the bowl in a plastic film and poke holes on this. The gnats can easily enter through the holes. But they can’t fly away and will drown because the soap will trap them.
- Bring in reinforcement with beneficial bugs
This may seem like exacerbating the issue. But there are beneficial nematodes. These will control the gnat population while not harming the plant.
These are microscopic roundworms that are the natural prey for gnat larvae. The reproductive cycle of gnats is 2-3 weeks long. So it will take 2-3 cycles to eradicate the gnats.
Nematodes also help to control other pests like thrips pupae and springtails. - Use sticky fly traps
Another way to trap the pesky flies is with sticky paper. You can buy a pack of these yellow stickers and attach it to a stake. Then, poke that stake into the soil of the most infected plant.
This method works like magic since the insects are attracted to the yellow paper. This is a way to control only the adult population of gnats. So it will take a couple of cycles (approximately 1 - 2 months) to fully get rid of the gnats.
Since you aren’t applying anything to the plant, this is one of the least harmful and best ways to get rid of gnats in plants naturally.
- Neem Oil Sprays
Neem oil sprays are a popular natural method to control many types of infestations in plants. All you need to do is apply a diluted solution of neem oil and water to the soil. This will kill the larvae.
The spray will also kill adult flies when they come in contact with the solution. So if you see the gnats swarming around, spray the air near your plant.
You can get a pre-made diluted solution or pure neem oil and dilute it yourself. Many plant parents vouch for the latter. - Invest in a flycatcher
If your infestation is bad but you want to try a natural method, then this is your best shot.
The machine uses UV light to attract the gnats. Next, the fan inside the machine sucks the gnat in. There is usually flypaper in the bottom which traps the gnats. You should periodically change this paper to increase the effectiveness of the flycatcher.
Here are some popular brands you can use.
FENUN
Katchy
EON Luxe Solutions - Bti Soil Drench
Bti or Bacillus thuringiensis israelensis bacteria kills the larvae of various insects. This includes mosquitoes, black flies, and fungus gnats. This is an organically accepted insecticide that doesn’t harm your plant or mammals.
You can get Bti in tablet, granule, or concentrated liquid form. When you’re diluting it, make sure to wear full-sleeved shirts and long pants. The bacteria takes 7-14 days to break down. So you’ll have to reapply the spray once every 2 weeks till the pests die. - Hydrogen Peroxide cocktail
This common cleaning agent is effective in killing gnat larvae. Mix 1 part of hydrogen peroxide with 4-5 parts of water. Then, spray the mixture onto the soil.
The peroxide kills larvae on contact. You will notice the soil fizzing. After a couple of minutes, the fizz turns into harmless oxygen.
You can also use this mixture to kill aphids and other unwanted insects. The only disclaimer is DO NOT use a concentrated solution. That will kill your plant. - Pyrethrin Spray
Pyrethrin is an organic compound that is found in Chrysanthemum flowers. It has strong insecticidal properties. The spray works by targeting the nervous system of the pests. It works on only the adult population of gnats.
Follow the package instructions when it comes to dealing with any commercial insecticide. The concentrations will change according to the brand.
Try to limit your exposure to the chemical, especially when you’re applying it indoors. Pyrethrin is toxic to honeybees and fish. So use it only as a last resort.
All these remedies for gnats in houseplants are effective. It will help you get rid of gnats so that your plant can remain healthy and you don’t have to deal with the flies on your face.
