Bacteria Thuringiensis (BT) is a natural bacteria which is hugely effective in killing gnats. However, these products are very expensive to buy. Fortunately, a much cheaper option is to buy something called mosquito dunks, or mosquito bits, which contain the same bacteria, although in a lower concentration.
Lysol Disinfectant Spray. The gnats that live and breed around your houseplants can be easily killed by Lysol or a store-brand disinfectant spray. Spray directly into the dirt and work it in and around the top soil, I use a fork. That's it. Pretty simple and works like a charm every time.
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.
Easy way to get rid of fungus gnats is to put in dish washing soap (one tablespoon) in a gallon of water mix well and water dry (bone dry preferable) soil thoroughly. Gnats will die ASAP. Simple and easy, has worked for me.
They are attracted to yellow, so you can also set traps or glue traps but the best thing is to hang vanilla and somehow ease them back out in the open. They will eventually find soil and not bother you if you keep up the good work. They can sit in old AC window units that were in storage, remove if you can do so.
Create a DIY gnat trap using vinegar
You can create your own DIY gnat trap by pouring equal parts of apple cider vinegar and water into a bowl. Leave the solution next to your plant. The adult gnats will be attracted to the scent, try to drink it and drown.
Fungus Gnat Deterrents
Fast-draining soils with inorganic additives, like perlite, vermiculite, and sand; Inorganic soil covers, like pebbles, coarse sand, chicken grit, or diatomaceous earth (Some swear by the gnat-killing power of diatomaceous earth!); Pyrethrin sprays approved for organic gardening.
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.
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.
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. .
However, it is also a great solution for a gnat infestation. Combine 20 drops of tea tree oil with a litre of water. Water the infested plants with this mix, and you should help remove any larvae in the soil. For the adults, use some adhesive traps around the plant.
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.
Place your pots in a container that can hold enough water to cover at least half of the pot, like a sink, bucket, or basin. Fill up the container with water between halfway and three-quarters up the side of your pots. Leave your plants in the water until the top of the soil becomes moist.
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.
The most common recommendation is to mix 1 part regular household-grade H2O2 with 3 parts water (H2O - notice the chemical similarity between water and hydrogen peroxide), and then apply this directly to the soil.
Conclusions. Based on the results obtained from our study, it is evident that Bounce original brand fabric softener dryer sheets repel fungus gnats.
Additionally, houseplants can harbor gnats, particularly fungus gnats, which lay their eggs in moist soil. The larvae then feed on organic matter in the soil, potentially harming plants and causing an infestation. Overwatering plants only makes this situation worse.
If you just have a couple scouts checking out the accommodations—as in, the gnats aren't swarming yet—fill a spray bottle with a cup of water, a tablespoon of vinegar, and a few drops of liquid dish soap and give it a good shake. Spritz gnats in flight to put an end to the infestation before it begins.
Because fungus gnats thrive in moist conditions, especially where there is an abundance of decaying vegetation and fungi, avoid overwatering and provide good drainage. Allow the surface of container soil to dry between waterings. Clean up standing water, and eliminate any plumbing or irrigation system leaks.
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.
Miracle Grow does have fungus gnats. Especially the nature's cure brand. I've used the Black gold organic potting soil a few times, indoor and outdoor, and have never seen a fungus gnat anywhere. Plus it's more like real dirt rather then the soft and unpredictable coco coir base.