Fungus Gnats

From Bloompedia


What are they:

  • Tiny black fruit-fly type of insects

Potential reasons:

  • Overwatering
  • Moist soil
  • New plant purchase that was not

Is this a concern?

  • No. Harmless to humans but a nuisance nonetheless.


The first step is to quarantine the plant and place it away from all your other plants to avoid cross-infestation.


There are two methods: potato slices or potato wedges.

  • Cut the potato into wedges and stick it into the soil but not so far that you cannot retrieve it [OR] leave slices face down on top of the soil.
  • Wait at least several hours.
  • Look at the underside of the potato exposed to the soil to see the gnats.
  • Replace potato and repeat.

Diatomaceous Earth[edit]

Imagine tiny glass shards cutting the gnats with each and every contact. DE is a naturally occuring sediment that comes in the form similar to white flour. Look for food grade DE and avoid inhaling it, as you would any sort of dust.

  • Sprinkle a layer onto the top of the soil

Apple Cider Vinegar, Wine, Beer, Dish Soap Mixture[edit]

The trick here is to get something sweet to attract the gnats into container and trap them there. Gnats will crawl into the container through the poked holes, get stuck, and die.

  • Use a container and add in a bit of either apple cider vinegar, wine, or beer with water.
  • Mix in a drop of dish soap to penetrate the top layer of the mixture.
  • Cover the container with plastic wrap.
  • Use a fork or toothpick to poke holes in the top.
  • Optional: use a rubber band to keep the plastic wrap in place.


  • Sprinkle cinnamon to the top layer of the soil.

Neem Oil[edit]

Soil Mixture[edit]



  • Avoid overwatering.
  • Wait until the first few inches of soil is completely dry before watering.
  • Use the finger test.