The most common cause of fungus gnats in plants is overwatering, so be sure to let your soil dry out in between waterings as often as possible. Check the soil with your finger every few days, and once you feel it starting to get dry, leave it like that for about a week to keep gnats away. .
Mix 1 part 9% hydrogen peroxide with 6 parts water. Allow top layer of soil to completely dry out before drenching the soil in the peroxide solution.
One of the easiest ways to prevent gnats is to let your soil dry out between watering. You may have to dehydrate it to the point where your plant looks a little droopy, but it works. Drying out the soil creates an inhospitable environment for gnats and prevents them from laying eggs in your soil.
Adult fungus gnats are attracted to the warm, humid environment that is an indoor herb garden. Gnats love moist soil and do not discriminate between healthy and unhealthy plants. It also doesn't matter what your herbs are potted in, be it a large planter or a small pot, fungus gnats have no problem setting up camp!
Ground coffee is not effective against gnats in plants. However, coffee grounds may make the fungus gnats problem even worse. Placing them on the soil's surface makes a barrier prone to mold growth and attracts fungus gnats. They thrive on decomposing organic debris, and coffee grounds provide plenty of that for them.
Use Lavender Spray Or Plants
Gnats are not fans of the aroma of lavender, so whether you want to plant your lavender because you enjoy the look as well as the scent or choose to use a liquid substitute to this scent, gnats will avoid it.
Mix equal parts of water and hydrogen peroxide. Use this solution for your next watering session. The hydrogen peroxide will target the larvae but not injure your plant. Hydrogen peroxide will also help with any root rot.
Sticky Traps
Flypaper or more modern decorative sticky traps are popular options to catch any fungus gnats buzzing around houseplants and windows. Small yellow sticky traps can be cut and placed on wooden stakes and inserted into pots close to the soil, where adults tend to crawl and fly.
With all that in mind, the EPA says that hydrogen peroxide in low doses is indeed safe for plants. The caveat is of course, in the concentration. Too much can damage plants.
Does Cinnamon Keep Fungus Gnats Away? No—but the idea that cinnamon could provide a natural method for controlling fungus gnats has some basis in reality. "Unfortunately, you can't count on cinnamon on or in the potting mix to help control fungus gnats," Hancock says.
Apply Hydrogen Peroxide
While traps help control the adult population of fungus gnats, you still need to treat the eggs and larvae in the soil. Make a solution by mixing 1 part hydrogen peroxide and 4 parts water, then pour the mixture into the pot, making sure to completely saturate the soil, says Royer.
A fungus gnat infestation is a common problem that's not likely to go away on its own.
The only way to get rid of gnats without killing them is to repel them with scents they don't like: vinegar, vanilla, pine oil, peppermint, lemon, eucalyptus, and lavender. Even dryer sheets could help. Of course, the first line of duty would be to get rid of the infestation's root cause.
Pair a hydrogen peroxide solution with a powerful spray bottle for the best results. Mixing water and hydrogen peroxide creates a solution that can be sprayed on plants to get rid of gnats without harsh chemicals. The solution helps kill gnat larvae and even deters adult gnats from laying eggs.
DAMAGE. Adult fungus gnats don't damage plants or bite people; their presence is primarily considered a nuisance. Larvae, however, when present in large numbers, can damage roots and stunt plant growth, particularly in seedlings and young plants.
Gnats are attracted to anything that smells fruity and sweet. Therefore, fruit-scented hygiene and beauty products tend to draw gnats into the house. Rotting food in the drain. A buildup of food in the drain would, over time, result in an infestation of house gnats.
If you're spraying or watering the soil for fungus, eggs or larvae, be certain you really soak the soil. If you have any of these problems, you can use hydrogen peroxide on your plants once a week.
Prevent Fungal Disease
MAKE IT: Mix 1 teaspoon of baking soda and 2-3 drops of liquid soap in 1 liter of water. Spray the solution on the infected plants. Baking soda helps the plants become less acidic and prevents fungal growth.
To get rid of fungus gnats, mix a solution of one part hydrogen peroxide with four parts water. Pour the mixture onto the soil around the infested plant.
Homemade gnat repellent spray: A mixture of dish soap, water, baking soda, and vinegar can be filled into a spray bottle. The mixture should contain a few drops of dish soap, a tablespoon of vinegar, and baking soda per cup of water. A few sprays of this mixture is an effective gnat repellent.
The peroxide kills fungus gnat larvae on contact. Neem oil is also an effective soil soak to combat fungus gnat larvae. Dilute the oil with water per the manufacturer's directions and directly drench the soil at the roots of the plant. You can also spray the upper portion of the plant to keep adult gnats at bay.
Combine equal parts vinegar and soap and then add a few tablespoons of sugar – once you mix it all together you can place the bowl wherever the gnats have been gathering. They will be attracted to the sugar and vinegar and drown in the mixture. Traps can also be made out of red wine and dish soap, or rotting fruit.
All plants can generally tolerate hydrogen peroxide, however it must be diluted. If it is left at full strength, it can bleach or damage leaves.
Many indoor gardeners use peat-lite mixtures, consisting of peat moss and either perlite or vermiculite. In more recent years, coconut coir (or coco coir) has become a popular, lower cost, and more sustainable alternative to peat moss. These soilless media are sterile, lightweight and easy to handle.
Root rot. In many cases of overwatering a plant, the roots will begin to rot and spread through the soil. Gnats come into play here because they love moist environments, so if you notice your plant has symptoms of root rot there is a good chance you may have fungus gnats.