Homemade Spray For Fungus Gnats: 5 Recipes

Small and pretty annoying, fungus gnats are little critters that manage to enter your home and sometimes ruin outdoor plants. You're probably tired of swatting them away so we've looked into this problem and in this post, we'll be sharing with you some homemade sprays you can use to get rid of them.

There are a couple of homemade sprays you can use to repel and kill fungus gnats. Some homemade sprays can be made using pantry items, while you can also use some chemicals you already have at home.

  1. Isopropyl alcohol and dish soap spray
  2. Castile soap spray
  3. Neem oil spray
  4. Essential oil spray
  5. Citronella oil spray

We know that fungus gnats can be pretty annoying and there are a lot of homemade sprays you can try to repel them. In this post, we've also come across some useful tricks that can help you lure and trap fungus gnats, so keep reading as we share this valuable information with you.

A fungus gnat photographed in great detail, Homemade Spray For Fungus Gnats: 5 Recipes

Homemade Spray For Fungus Gnats: 5 Recipes

After bringing home some indoor plants, you might've noticed these little critters zooming around inside your home. You might see them buzzing about your computer screens while you're working, annoying and distracting you from your tasks. These little bugs are called fungus gnats.

A big black male fungus gnat captured in great detail

Fungus gnats are small flying insects that are about 2.5 millimeters in size, and they are dark with long legs. These tiny bugs are harmless to humans and pets, but they can get annoying pretty quickly. They're attracted to carbon dioxide, so you will often see them darting about close to you.

How Do Fungus Gnats Get Inside?

If you find that there are fungus gnats inside your home, they most likely got inside because of unsterilized soil coming from houseplants you might've bought from the nurseries. Fungus gnat eggs are laid on moist soil. The larvae feed on the soil before they pupate and mature.

A black fungus gnat on the leaf

The sudden swarm of these annoying little bugs can drive you a little crazy, and you might be looking for ways to get rid of them quickly. While you can easily do that with insecticide, you can find alternative spray solutions with some items you already have at home using these easy recipes.

Make sure to purchase a clean, unused spray bottle for these solutions and label them properly. Keep these homemade sprays close by to spray on your houseplants to get rid of these pesky fungus gnats.

Get these spray bottles on Amazon.

1. Isopropyl Alcohol and Dish Soap Spray

A quick and easy homemade spray to get rid of fungus gnats can be made with isopropyl alcohol and your favorite kitchen dish soap. The dish soap helps the solution stick to the gnats, and isopropyl alcohol is drying, so it will kill the gnats in no time.


  • 1/2 cup water
  • 1/2 cup isopropyl alcohol
  • 1 teaspoon dishwashing soap


In a clean spray bottle, mix together 1/2 cup of water, 1/2 cup of isopropyl alcohol, and 1 teaspoon of dishwashing soap. Shake the bottle to mix the solution well.

Use this homemade spray on areas where you see fungus gnats like sinks, drains, and plant pots. Before spraying on a live houseplant, make sure to test it out on a small leaf to check that the alcohol won't burn or damage your plants. This solution works better on hardier less sensitive house plants.

Do not spray this solution on items that you will be consuming like fruits or vegetables. Only use this spray on surface areas and live gnats. When using isopropyl alcohol for this spray, make sure to get 99% isopropyl alcohol and wear safety gear like gloves when handling.

Check out this isopropyl alcohol on Amazon.


2. Castile Soap Spray

Castile soap is made from pure vegetable fat and it is all-natural, non-toxic, and completely biodegradable. This soap contains fatty acids which break down the tough exterior of most soft-bodied insects like fungus gnats, which kills them.

Check out castile oil soap on Amazon.


  • 1-quart water
  • 2 teaspoons castile soap


In a spray bottle, add 2 teaspoons of castile soap to 1-quart of water and shake the bottle to mix the solution. When using, do an initial spray on your plant's leaves (some plants are sensitive) and leave for a few hours to check for damage.

You can use this solution to spray on your pots, the soil, the leaves, and other surrounding plants. Since this is a natural mixture, it won't instantaneously kill the fungus gnats so you will have to repeat the process after three days. Do this about three to four times or until the fungus gnats have all disappeared.


3. Neem Oil Spray

One of the most popular all-natural insecticides used by plant lovers is neem oil. This naturally occurring pesticide comes from the seeds of the neem tree. The oil is known to suffocate the insects by blocking their breathing openings, which effectively kills these pests.

Get this cold-pressed neem oil on Amazon.


  • 1-gallon warm water
  • 1-teaspoon dishwashing soap
  • 1 or 2 tablespoons pure cold-pressed neem oil


In a clean container, pour 1-teaspoon of dishwashing soap into 1-gallon of warm water. Mix thoroughly. Add 1 or 2 tablespoons of pure neem oil and stir to mix the solution properly. Transfer to a clean spray bottle.

Start by trying the spray out on a small leaf or part of your plant, and leave it on for a few hours or overnight. If the plant does well with the neem oil solution, thoroughly mist the leaves and the soil to kill fungus gnats.

Use weekly if you are trying to control an infestation, and bi-weekly for preventive measures.


4. Essential Oil Spray

Some essential oils are natural repellants for insects, which is why it's a great alternative to insect sprays for fungus gnats. These insects particularly hate some essential oils like rosemary, peppermint, eucalyptus, patchouli, cedarwood, and geranium, so these are great to add to your homemade spray.

Check out this Thieves cleaner on Amazon.


  • 2 capfuls of Thieves cleaner
  • 1-teaspoon dish soap
  • 2 cups water
  • 1 drop cedarwood oil
  • 1 drop peppermint oil
  • 1 drop rosemary oil


In a spray bottle, mix together 2 cups of water with 2 capfuls of Thieves cleaner, 1-teaspoon of dish soap, 1 drop each of cedarwood, peppermint, and rosemary oil. Shake the bottle vigorously to thoroughly mix the solution.

To use this spray, make sure to spray your plants and soil every four days, for an entire month or until you have controlled the fungus gnats infestation. Make sure to spray the plants consistently to remove and kill the gnats.


5. Citronella Oil Spray

Citronella is another natural repellant that a lot of insects including fungus gnats hate. This is because citronella conceals carbon dioxide and lactic acid, which these gnats love.

This spray does not necessarily kill fungus gnats, but they are enough to repel them while you use other methods to kill their eggs and larvae.

Get this citronella oil on Amazon.


  • 2 cups water
  • 2 teaspoons citronella oil
  • 6 drops of dishwashing soap


In a clean spray bottle, mix together 2 cups of water, 2 teaspoons of citronella oil, and 6 drops of dishwashing soap. Shake to mix thoroughly. Spray the solution on areas where you typically find fungus gnats, especially your plant pots.


How To Trap And Prevent Fungus Gnats

A homemade recipe for removing and killing fungus gnats

Before you can kill and effectively get rid of fungus gnats from your home, you'll have to trap them. Prevention should also be done to keep them from infesting your indoor space again.

Gnat Traps

A popular way to trap gnats is by using good old apple cider vinegar. This method is a classic way to trap fungus gnats because they are attracted to the acidity and sweetness of the solution.

To make this solution, simply mix a couple of tablespoons of apple cider vinegar, a few drops of dish soap, and a tablespoon of sugar in a bowl. Stir with a spoon and set these traps close to plants or wherever you see fungus gnats.

A yellow fly trap sticky paper

The vinegar and sugar attract the gnats, and the dish soap drowns them in the solution.

If you don't have apple cider vinegar, you can also use red wine (perfect if you want to dump out that stale wine you had from dinner last night) and some dish soap. Set out a few bowls of these wine traps to get rid of fungus gnats.

Preventing Gnats

Once you've gotten rid of all the eggs, larvae, and adult fungus gnats, it's important to keep it that way. Prevent them from coming back by watering your indoor plants just enough, because overwatering attracts them to lay their eggs in the soil.

You can also cover the soil with horticultural sand or diatomaceous earth to prevent gnats from laying eggs on the soil. This is because these materials dry pretty quickly even after watering, so fungus gnats do not have the time to lay their eggs and pupate their larva.

Wrapping Things Up

A fungus gnat photographed in great detail

There are a lot of methods that you can try to get rid of and repel fungus gnats from swarming your home. Whatever choice works for you, make sure to also clean up your indoor plants and the surrounding areas to prevent them from invading your home again.