Using hydrogen peroxide as an outdoor fungus gnat killer

Robert James
Pest Control Technician

Fungus gnats are a threat to your green surroundings. These gnat types depend on plants for their survival, unlike other gnats. Hence, it is important that you get rid of fungus gnats to protect your garden.

Hydrogen peroxide, used as a mild antiseptic, can also be used for treating fungus gnat issue.

In this article, you will learn how you can use hydrogen peroxide as a fungus gnat killer.

Hydrogen-Peroxide as fungus gnat treatment

The hydrogen peroxide solution


You will need two things:

  • Hydrogen peroxide (3%)
  • Water

Mix hydrogen peroxide with water in a 1:3 ratio i.e. one part of hydrogen peroxide to three parts of water to get the required solution.


You can use the solution to water the soil as you would normally do. However, do ensure the soil is dry before application.

Repeat application until your plants are free from gnats.

How it works

This solution is very effective in combating gnat larvae, killing them instantly on contact.

There will be some fizzing in the soil after application. The fizzing stops once the hydrogen peroxide breaks down into water and oxygen molecules.

Besides, this hydrogen peroxide solution will prevent adult gnats from breeding on plants. For combating against adult gnats, mix two tablespoons of vinegar and few drops of dish soap to the solution.

However, do not use this vinegar-dish soap solution excessively as you risk killing your plants. Apply this solution after every three-four watering sessions. If you water your plants daily, use this solution every three or four days.

Some ways to avoid gnat breeding

Apart from using the hydrogen peroxide solution, here are a few things you can do to keep your surrounding gnat-free:

Avoid excess watering of plants

Excessive water content in soil invites gnats as it provides an ideal breeding space. Hence, keep your watering activity to a bare minimum.

Use neem oil

Neem has repelling properties that can help you keep gnats and other insects away from your surroundings. For this purpose, mix some neem oil in water as per manufacturer recommendations.

Use this soil to water your garden. Moreover, you don’t have to worry about killing plants in your garden when using neem oil for driving gnats away.

Use a mix of essential oils

Essential oils also have gnat repelling properties. You could use essential oils of peppermint, rosemary, cedarwood, or eucalyptus for this purpose.

Prepare a mixture of two or three of these essential oils with some distilled water and few drops of vinegar to make an effective gnat repellent solution.

Hydrogen peroxide is a potent remedy...

For treating fungus gnat issue in your garden. We hope you find this information useful and can get rid of gnats.

If you have any questions, do leave them in the comments.

Check the homemade gnat trap article for other options.

crosschevron-down linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram