How To Get Rid Of Gnats In Houseplants?

Common gnat, Culex pipien, in front of white background
Common gnat, Culex pipien, in front of white background

Have you noticed gnats flying around your houseplants? Although gnats are harmless, they are very annoying to have in the home. Do not throw away your houseplants; this is an easy issue to solve! Gnats are also known as fruit flies and they can originate on houseplants, items in the trash, or fruit left out too long. They can become an epidemic quickly since gnats have the ability to lay up to 300 eggs in an average life span of two to four months. The number of gnats can quickly explode into the thousands.

Depending on how severe the gnat problem is, you can first try removing any food sources they have been feeding from. This would include removing any fruit left out on counters. Any houseplants should be ideally planted in containers that can drain since gnats also love wet, standing water on top of soil. Your plant’s soil should be moist but not overwatered. The trash should be taken out often, or even stored outside until the gnat issue is solved since gnats also love any type of decomposing food. Wash any plates right away; do not leave dirty plates with food particles stacked in the sink. Dirty plates are a buffet invitation to gnats! Check your cabinets to make sure there is not a spill of some sort in the cabinet, gnats may be feeding off of the spill as well.

It is also a good idea to spray all of your houseplants on the same day with a plant-safe garden and fruit insect killer. These sprays are available at many home improvement, large retail, and gardening stores. Ask the staff working there for a recommendation on which product is best, they talk to many people with the same issue. Be sure to mention if you have pets or children, since some sprays contain chemicals that can be dangerous. Spraying the plants on the same day is important since gnats will travel to a chemical-free plant. Wait the amount of time recommended for the product to work, for example many products recommend a weekly or bi-weekly application if the problem persists.

Cleaning all window sills and frames also will help. You will typically find mostly dead gnats in window areas but if there are any live gnats this will help kill them. An insect spray can be sprayed around the windows, in combination with cleaning if you notice a high number of gnats at that location.

Many people believe it is necessary to remove all the soil from the plant and re-pot with new soil. This can harm your plant, as it is needlessly shocked into adapting to the new soil. If gnats have laid eggs in the soil, it is generally in the very top layer of soil. Removing a half in to an inch of soil from around the plant should be sufficient to remove any eggs. Replace new soil on the top layer, if needed.

There are a few home remedies that can be tried as well if you wish to try and avoid using spray chemicals. When watering your plants, add a tablespoon of dishwashing soap in the watering can. The houseplants will not be hurt by this but gnats cannot live around soap and they will be much less likely to lay eggs in the soil. Also, gnats are attracted to vinegar. Use a plate with rounded sides or a flat bowl and fill the container with a quarter to a half inch of vinegar. Cover this with plastic or saran wrap and cut a few very small slits across the top. The gnats will be stuck in the vinegar and this can be drained and re-filled once several gnats have been caught. You can put vegetable oil on any surface where you have noticed a lot of gnats. Gnats coated in vegetable oil can no longer breed. These home remedies will take a little longer to work, but when combined with aggressive cleaning they can be just as effective as chemical solutions.
Waiting will only make the infestation worse, so try the solution that works best for you today.


Author: Neil

Neil Wardlow has been writing professionally since 1989. Neil discovered he enjoyed writing when he suffered an injury during his 15-year building construction career. Neil now writes full-time, whenever he’s not occupied with entertaining family and friends, growing things, or making repairs in and around his beautiful ranch house.

10 thoughts on “How To Get Rid Of Gnats In Houseplants?”

  1. Thanks for the tips Neil. I’m going to have to put these to use soon. And here I was thinking I’d need to change our the organic soils I use.

  2. I noticed right away after coating the rim of my plant pots with vegetable oil that the gnats once they landed, they’re stuck and eventually dies. Not sure about the vinegar since I didn’t notice any of them attracted to the dish.

    1. Hi,! The vinegar trap does work fairly well tool The vinegar shouldn’t be added directly to the potted plant, but it does work effectively when placed in a small dish or other types of containers. We’ve been talking about the vinegar and soap solutions on this THF forum thread too:…. You may find some of those posts helpful too.

    1. JB, using sand over the soil does usually help to keep the gnats from laying eggs in the moist potting soil. However, from what I’ve read on other forums, that sand layer should be about an inch thick, and the soil & sand should be cycled out after the gnats die. I’ve also read that you should try watering the plants via a saucer of water under the pot or through a tube inserted below the surface of the soil, to avoid the soil becoming too moist. I’ve also heard that using old coffee grounds works to get rid of gnats.

  3. I have been fighting gnat infestations periodically over the years. Especially when I bring plants in the house to winter over. Don’t ask me about how this happened but my wife left old bananas in a bag on the counter over night. They were already peeled and in the morning there was a brownish liquid in the bag, lots of it. Gross, but I thought… I’m going to try something with this mess. I cut the liquid with about 50% water, put it in a dish with about 10 drops of liquid dish washing soap, and I kid you not – in three hours there were 40 dead and dying gnats in the dish. Seemed to work much better than the apple cider vinegar traps that have been out for a week with much less success. You will not be disappointed. I will also emphasize, these were not fruit flies. These were those pesky house plant gnats.

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