Updated: Apr 17
Fungus gnats are small black flying bugs, in size somewhere between a fruit fly and a small mosquito. Some may mistake them for fruit flies, but whereas fruit flies are generally found around your food, fungus gnats are found on the surface of the soil or around your plants.
While it is lovely to have a house bursting with plants, having a house bursting with fungus gnats is not! Unfortunately these pesky little bugs are a common problem on plants indoors. While the mature fungus gnats do not bite or harm plants they can be annoying and unpleasant to have in your home. The larvae on the other hand live in the top inch of your plant's soil and can damage the tender roots causing harm to your plants, especially younger plants.
The good news is there is a number of natural ways to get rid of fungus gnats! Choose a few of them to try, or try them all, whatever works best for you.
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8 Natural Ways to Get Rid of Fungus Gnats
1. Sticky Paper - Sticky paper meant for catching flies and bugs gives you a quick and easy start to controlling and managing mature fungus gnats. Keep in mind you will still need to treat the larvae in the soil. I purchased a large pack from Amazon. I think I will have enough to last me years!
2. Hydrogen Peroxide - Diluting 1 part hydrogen peroxide with 4 parts water and allowing this to soak the top 2 inches of your plants will kill fungus gnat eggs and larvae in the plant soil. It works best if you use this when the soil is on the dry side. You may hear the peroxide fizzing, this is normal. Fungus gnats develop from egg to an adult gnat in 3 to 4 weeks. You will want to repeat the peroxide treatment once a week for 4 consecutive weeks to ensure any new eggs that may have been laid during the treatment process are destroyed.
3. Bottom Watering Your Plants - Fungus gnats thrive on warm, moist soil. To reduce fungus gnat growth, water your plants from the bottom for the duration of your fungus gnat infestation. Set plants in a pan of water and allow them to soak up water, keeping the top two inches of the soil dry, rather than pouring water on the surface of the soil. This works well with larger plants but does not work when you are growing seedlings that may only be planted in two inches of soil to begin with. Keep watering to a minimum and plants on the dry side for the duration of your fungus gnat infestation.
4. Cinnamon - Cinnamon is a natural insect repellant. It is relatively inexpensive to buy. Sprinkle a layer of cinnamon on the surface of your plant soil to discourage fungus gnats.
5. Diatomaceous Earth - Diatomaceous earth, or DE for short, is made from fossilized remains from aquatic organisms. Its small edges are abrasive to insects, cutting into their exoskeleton and killing them. DE works only when dry. Take care not to inhale as it can be damaging to lung tissue. To use diatomaceous earth for fungus gnat treatment, sprinkle on the dry surface of your plants and keep it dry by only bottom watering your plants for 4 weeks.
6. Neem Oil - Neem oil can be used to treat fungus gnats by spraying thoroughly on plants and soil every 4 days for 4 weeks.
7. Young Living Essential Oil Spray - I have made this essential oil spray using Young Living Thieves cleaner along with a few other oils and have had success treating a variety of plant pests. Use the recipe below and spray plants and soil every 4 days for 4 weeks. The key here is consistency.
8. Sand - Cover the surface of the soil with 1/4 inch layer of sand to prevent fungus gnats from burrowing into the soil to lay eggs.
Fungus gnats can be so persistent and can be quite difficult to completely get rid of. One female can lay up to 200 eggs! As far as what treatments you choose, I would suggest for sure trying to go easy on the watering and allowing your plants to stay on the dry side then choosing a spray or a soil treatment and staying very consistent with it for the 4 week life-cycle duration of a fungus gnat.
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