To get rid of gnats in plants, it is essential to target both the adult flies and their larvae in the soil. The most effective approach is to combine multiple strategies, as detailed below.[3]
- Let the soil dry out between waterings: Fungus gnats lay eggs in moist soil. Allowing the top few inches of soil to dry before watering creates an inhospitable environment for egg-laying and larvae development.[2][5]
- Use sticky traps for adults: Bright yellow or green sticky traps placed near or in the soil catch adult fungus gnats, helping break the reproductive cycle.[3][4]
- Drench soil with organic treatments:
- Apply chamomile tea or sprinkle cinnamon on the soil to reduce fungus and thus the gnats’ food source.[1]
- Hydrogen peroxide solution: Mix one part 3% hydrogen peroxide with four parts water, and water your plants with this mixture to kill larvae in the soil.[5]
- Apply Bacillus thuringiensis var. israelensis (BTi) products, such as mosquito bits, to target larvae without harming plants.[5][3]
- Top-dress with sand: Add a 0.5-inch to 1-inch layer of sand on top of the soil. The coarse texture inhibits adult gnats from accessing the soil to lay eggs while still allowing water through.[4][5]
- Use potato slices as larva traps: Place raw potato slices on the soil surface; larvae will migrate into the potato. Discard and replace the slices every few hours until the infestation declines.[1]
- Employ apple cider vinegar traps: In a shallow container, mix apple cider vinegar with a few drops of dish soap. Cover with perforated plastic wrap. Gnats are attracted to the scent, enter the holes, and drown.[4]
For prevention:
- Inspect and quarantine new plants before adding them to your collection.
- Ensure pots have good drainage and don’t leave water sitting in saucers.
- Bottom watering can help keep the soil surface drier, discouraging gnat breeding.[6]
References
- [1] Weapons of Gnat Destruction: A Guide to Killing Fungus Gnats
- [2] Prevent Fungus Gnats – Three Easy Methods
- [3] The easy way to get rid of Fungus Gnats in indoor plants
- [4] Avoiding Indoor Plant Infestation: Fungus Gnats
- [5] How to Get Rid of Fungus Gnats in Houseplants Potting Soil
- [6] Pest Control, Prevent Fungus Gnats on Houseplants
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