Does Epsom Salt Kill Fungus Gnats?

Epsom salt is an effective pesticide that both repels and kills pests on contact. 

Many homeowners use it to get rid of pests like ants and beetles in their homes and gardens.

But does Epsom salt kill fungus gnats? 

And can you able to get rid of fungus gnats, forever, with Epsom salt?

Keep reading to find out.

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Does Epsom Salt Kill Fungus Gnats?

Does epsom salt kill fungus gnats

Yes, Epsom salt kills fungus gnats. Epsom salt contains magnesium sulfate, which is toxic to fungus gnats. 

It’s lethal for fungus gnats, their eggs, and larvae when they come in contact with Epsom salt.

How To Use Epsom Salt To Kill Fungus Gnats?

The key to killing fungus gnats with Epsom salt is to use it in places where they inhabit.

Fungus gnats live and breed in places with decaying organic matter like foliage and compost pits. 

Other favorite places for fungus gnats are overly wet plant soil beds in your garden and your indoor potted plants.

To kill fungus gnats, all you’ve to do is spray a mixture of water and Epsom salt on these places.

And prepare that mixture is so easy that even a five-year-old can do.

To prepare a fungus gnat killer with Epsom salt, take one cup of Epsom salt and mix it with four to five gallons of water. 

Stir the mixture well and pour the mixture into a spray bottle. 

Then spray it on the wet plant soil beds (both inside and outside your home), decaying organic matter, gutters, and trash bins.

The spray will kill the adult fungus gnats and their larvae living in those places.

On top of that, the Epsom salt spray will also kill common garden bugs like beetles, ants, snails, and slugs. 

But one drawback is that Epsom salt will also kill earthworms in the soil. Earthworms are beneficial for the earth because they improve soil productivity.

Will The Epsom Salt Spray Damage Plants?

When used excessively, yes, Epsom salt can cause damage to your plants. 

Excessive and repeated use of Epsom salt on soil increases the magnesium levels of the soil.

High levels of magnesium and sulfur cause degrowth in plants, and some cases, it can kill the plants too.

But when used sparingly, Epsom salt can be beneficial to plants!

If the soil has a magnesium deficiency, then using Epsom salt on the soil will increase it. That will lead to better plant growth.

In potted plants, experts believe that it’s better to use it on Epsom salt on leaves rather than applying it directly to the soil. 

So, you shouldn’t use Epsom salt as the only means of bug control in your garden or potted plants. 

If you do, then you’d be harming, and eventually killing, the plants in the longer run.

What Is The Fastest Way To Get Rid Of Gnats In Your Garden?

Fungus Gnats On Indoor Plant

As you know, fungus gnats live and breed on wet soil and decaying organic matter in your yard or garden. 

So, to begin with, clean your garden. 

Get rid of any decaying organic matter like foliage, rotting pieces of wood, and empty the trash bins in your garden too.

Cleaning your yard will make your garden inhospitable for fungus gnats.

After cleaning, either make a spray of dish soap or white vinegar mixed with water. Both dish soap and white vinegar kill fungus gnats. 

After spraying, scatter some dry soil or sand over the soil if the soil bed is too wet. 

That will dry the soil, and it’ll prevent future fungus gnat infestation. 

To prevent fungus gnats from coming back, don’t overwater the soil and keep your yard or garden clean. 

Overwatering the soil increases the soil dampness, which attracts fungus gnats and many other types of pests.

Does Neem Oil Kill Fungus Gnats?

Essential oils, especially neem oil, eucalyptus oil, and peppermint oil, kill and prevents fungus gnats

The best part is that these essential oils are harmless to plants and the soil. 

All you’ve to do is add 3-5 drops of neem essential oil to the water. Mix it well and spray the mixture on the places where you see fungus gnats. The spray will kill the fungus gnats on contact. 

But here’s the catch.

To make it work, you’d need to use quality essential oils. 

Reliable essentials are cold pressed, 100% plant extracts, and they come in dark small glass bottles. 

And they’re a bit expensive too. 

Cheap essential oils are fragrances mixed with chemicals and vegetable oils. They reduce the insecticidal property of essential oils, and they’re also not healthy for plants.

So, refrain from buying mixed or impure essential oils. 

Should You Use Hydrogen Peroxide To Kill Fungus Gnats?

Hydrogen peroxide works better when you’re using it to kill the larvae of the fungus gnats living in the soil. 

It repels the adult fungus gnats, but it’s not effective in keeping the adult ones away forever. 

It’d be best if you use dish soap, white vinegar, or essential oils to get rid of fungus gnats in your home and garden. 

But keep in mind that white vinegar is also acidic, and you should use it sparingly too. 


Epsom salt kills fungus gnats. But you shouldn’t use Epsom salt often on plant soil beds to kill fungus gnats because over usage can damage the soil and the plants.

As an alternative, you can use neem essential oil. Neem essential oil kills and repels fungus gnats.