Last Updated on July 30, 2021
Plenty of homeowners are left wondering how to get rid of flies in house plants when they first start decorating their homes. A beautiful collection of indoor plants is an excellent way to bring life and colour into your life. Unfortunately, seeing tiny fruit flies, fungus gnats, and other unwanted intruders among the leaves and flowers can often leave you feeling frustrated.
The unfortunate truth is that all kinds of insects naturally feed on the plants in our outside world. If insects also find they can get a good meal from the plants inside your home, they’re likely to take advantage.
The kind of pests you get will often depend on the type of plants you’re growing. The most important thing to remember is that you can control and even get rid of unwanted flies with a few simple steps. However, prevention is often much easier than treatment.
Know Your Pests
First, if you want to get rid of unwanted flies on your house plants, you need to know what kind of insects you’re dealing with. The strategies for getting rid of fungus gnats are different than those for removing whiteflies, for instance.
Identifying the insects means getting up close and personal with your plants. Make sure you pay close attention to the kind of creatures crawling on the leaves or soil whenever you can. It might be helpful to set up some yellow sticky traps, too, so you can capture any pesky flies for closer inspection.
The Most Common Perpetrators
The most common pests encountered by gardeners for indoor plants are fungus gnats. These are similar to soil gnats, with black or grey wings, and are pretty small, usually only a few millimetres in length. The fungus gnat can cause a lot of damage by laying eggs in and around potted plants.
Commonly confused with fruit flies, fungus gnats are slightly different because they prefer to live in succulents and similar plants rather than living near fruits. These pests like moist soil, as well as decaying plant matter – such as dying leaves. Gnats flying around your houseplant soil could indicate the impending arrival of hundreds of larvae.
Another option could be the whitefly, which looks similar to a moth. These flies generally like leafier plants, so you usually find them crawling around your plant leaves. The flies leave many eggs underneath the leaves, and they can last for up to 3 months. It usually takes around 25 days for these creatures to grow beyond the larval stage and start consuming your beloved plants as adults. Whiteflies aren’t particularly tolerant of colder climates, so they’re more common in warm homes.
How to Get Rid of Flies and Fungus Gnats
Whether you want to control gnats around your plants or you’re struggling with whiteflies and fruit flies, it’s best to stay away from dangerous insecticides and chemicals. Products like hydrogen peroxide on the top layer of your plant soil might kill gnats and their larvae. However, they can also stop new plants from growing too.
To reduce the number of fungus gnats in plants, we firstly recommend making sure you keep a close eye on your plants and remember to get rid of dead leaves and other debris from around the plants whenever you can. You can also try some of the following tips:
Adding Dry Soil
Most gnats and fungus flies prefer living in soil with a certain level of moisture. Adding a thick layer of dry soil to the top of your plant’s bedding or allowing the soil to dry out naturally can help drive the gnats away. The biggest danger of this strategy is that while you may kill off larvae and gnats, leaving your plants without water for a week or longer isn’t always a good idea.
Succulents and other plants designed to withstand difficult conditions will survive a short time with dry soil. However, there will be plant options that can’t cope with having their soil dry or that long. Research your plants before you start using the drying method to get rid of gnats to ensure your plants stay happy and healthy.
If leaving your plants to survive in dry soil doesn’t seem like a good idea, you can take an alternative route. Another good way to get rid of whiteflies is to use excess moisture in the form of a high-pressure spray. A high-pressure spray of water will knock eggs and nymphs off your plants.
Although this process won’t have any long-term impact on your infestation, it should disrupt the fungus gnats and whitefly larval stage and make it easier to deter bugs from staying nesting in your plants.
An insecticidal soap placed in a shallow dish is a common option for getting rid of pests attracted to organic matter. If the soil drench or soil drying strategy doesn’t work for you, try making an insecticidal soap yourself, or you can usually find options to buy it online and from local garden centres. In general, insecticidal soap involves adding castile soap to water.
Apply the soap to the plant leaves and around your plants after the sun goes down to avoid sunburn and damage. It should help to reduce the presence of fungus gnats and other flies.
Neem Oil for Fungus Gnats
If you want an effective and natural way to get rid of gnats and flies, consider neem oil. It is a natural substance from the neem tree, which is excellent for getting rid of pests. To use neem oil around your newly purchased plants, make a solution to drench the soil by diluting the oil with plenty of water. You can even spray the leaves of your plants too.
For whiteflies, you’ll need to make sure you get the neem oil directly on the undersides of the leaves, as this will be what the white leaves are most attracted to – more so than organic matter around the plant’s base.
To remove the larvae, many gardeners turn their plants upside down to clearly see the little critters. A useful trick is to use plastic wrap to keep the soil and organic matter in place when turning the plant container on its head.
Other Ways to Get Rid of Flies
There are tons of tools homeowners can use if their plants become a breeding ground for fly and fungus gnat infestations. Even tiny flies can have a huge impact on your plants, soil and any ripe fruit growing. Here are some quick additional strategies you can use to disturb the fly life cycle or get rid of adult gnats completely:
- Make a sticky trap: You can make a sticky trap with a small index card, a highlighter, a wooden stick and some petroleum jelly. Highlighting the stick will attract all kinds of fruit flies and gnats during various life cycle stages. Coating the stick with petroleum jelly will cause the fungus gnats and fungus gnat larvae to stick in place.
- Smother the soil: Gnats and fruit flies lay their larvae on the top layer of soil, so try to disrupt that pattern. Laying gravel or coarse sand on the top of the soil will smother the larvae and prevent them from growing into adult fungus gnats. Make sure you pack the top layer well to get the best results.
- Make a DIY trap: You can make all kinds of traps to prevent fungus gnats with things like liquid dish soap, a neem oil mixture, and more. One option includes adding a drop of liquid dish soap to water with a small amount of apple cider vinegar. It attracts houseplant pests while preventing them from getting into your plants.
- Repot your plants: If the sticky stakes and traps around your plants are constantly full of insects, then it may be time to take a different approach to pest control. One option could be to sanitise the existing plant, removing as much infested soil as possible without disturbing the roots. Place the plant in a new pot away from any fungus gnat infestations. Remember, you will need to apply brand-new potting soil and remove all of the old potting soil if there’s a deep infestation.
- Use carnivorous plants: If adding unused potting soil to a new planter and changing the position of your plant doesn’t help with your fungus gnat infestation, why not try a natural solution? Get a carnivorous plant and place it next to the plant you want to protect. The new plant will help to get rid of fungus gnats and protect your plant from root rot.
- Use a spray bottle: A spray bottle can be a great way to keep your potting mix moist and address a potential fungus gnat problem. Use the spray bottle with your insecticidal soap for regular pest control. Simply spray the top of the soil, under leaves, and wherever gnats lay their eggs.
Can I Spray My House Plants With Vinegar?
Generally, spraying your house plants with vinegar isn’t a great idea. However, you can always create your own insect traps and place them next to your plants to attract gnats and pests.
Using Vinegar Against Pests
Pour around a quarter inch of apple cider finger and some fruit juice into a disposable plastic cup.
Add a drop of dish soap to the mixture and stir everything to make sure it’s blended. Cover the top of the cup and secure the soap mixture with a rubber band. Poke some holes into the plastic wrap on the top of the cup to allow insects to get in but not get out. Your gnats and other insects should be attracted to the trap next to your plant.
You can also use sticky paper and other traps to boost your chances of getting rid of any infestations.
How to Prevent Flies in Potted Plants
As noted above, it’s much easier to prevent insects from destroying your house plants than it is to get rid of an existing infestation. The best way to prevent fungus gnats and flies from taking over your home is to monitor your plants regularly. Keep an eye on your plants and look for any fungus gnats, their larvae, or signs of damage from fungus gnats.
The Importance of Watering
Adjusting your watering habits can be a good idea if you find that you frequently over-water your plants, as fungus gnats are attracted to moist surroundings. Consider testing the soil with your finger and only watering it when the soil is dry more than a couple of inches down. If you struggle with checking moisture yourself, you can get a sensor gauge to help.
Ensuring Good Drainage
Make sure your plants have the right pot for drainage, as this will also help to deter fungus gnats by ensuring there isn’t a lot of water at the bottom of the pot. Additionally, make sure you have the right type of soil. A well-draining soil that is slow to decay will be a good choice if you’re dealing with fungus gnats.
Finally, make sure you trim dying or dead foliage and any leaves from around your plant. Decaying plant material will attract all kinds of fungus gnats and flies.
Get Rid of Flies in Your House Plants
Overall, learning how to get rid of flies in house plants is the first step to do to keep your house plants free from flies. You just need to follow the right guide to make these pests stay away from your plants.
If you have any other useful tips for getting rid of flies and fungus gnats, we’d love to hear about them in the comments below.