You may have spotted some little flies hanging around your houseplants and thought nothing of it, and then a few days later, BAM! The number of flies has multiplied. Welcome to the world of gnats in houseplants!
Want to banish them? Read through our guide on what causes these pesky little flies in houseplants, and how to get rid of them. We’ve included some information to help with houseplant fungus identification, as infected plants can attract fungus gnats, and some top tips on how to treat these fungal infections.
Hopefully, by the end of this, you’ll be clued up about what to keep an eye out for to stop fungus gnats in their tracks.
The Bromeliad is known to be less susceptible to Gnats.
What Are These Flies In Houseplants?
These pesky flies in houseplants are called Fungus Gnats. They are little brown flies around 3-4mm long that like to nest in moist soil. The larvae of fungus gnats can cause damage to seedlings and cuttings, which is a nuisance to any horticulturist. But generally, they do not cause damage to houseplants and aren’t harmful to us.
This means most of the time, flies in houseplants are simply an annoyance. And although they aren’t very good at flying (so you won’t find them flying around the house too much), they are attracted to carbon dioxide - so you may find them flying towards your nose and mouth!
How To Detect Flies In Houseplants?
Potato Detection
Gnat larvae love potatoes. When you have lots of plants, it can be difficult to detect which one has flies flying out of it, so using potatoes is a great way to draw them out.
To do this, cut up a raw potato into slices and place them on top of your houseplants’ soil. Fungus gnat larvae will start to move towards the potato within a few hours, but it’s best to leave it overnight to see how serious the infestation is. Once you’ve sussed out the situation, choose your most preferred way of getting rid of flies in houseplants from below.
How To Prevent Gnats In Houseplants?
Avoid Overwatering
The best way to prevent gnats in houseplants is to avoid overwatering, as they will be attracted to the wet soil to lay eggs.
Make Sure Your Plant Has Good Drainage
Make sure your plant pots have good drainage, as this will allow the excess water to drain out of the plant. Without good drainage, the soil will remain moist which will create the perfect environment for gnats to lay eggs.
Snake plants love dry environments and are less prone to get Gnats.
Getting Rid Of Flies In Houseplants:
Dry Out The Soil
One of the simplest ways to deal with gnats in houseplants, especially if you don’t have too many of them, is to let the soil dry out. Once the soil dries out, your houseplant will be uninhabitable for the fungus gnats so they will eventually die off.
You don’t need to worry about the effect of missing a watering on your plant, as most plants can go quite a while without being watered before they start to die.
Sticky Traps
As the adult flies in houseplants are the biggest nuisance, you may want to reduce the number of them flying around your house while you deal with the young to get rid of them completely.
One of the easiest ways to do this is with sticky traps. These are usually yellow coated in a sticky non-drying adhesive. The flies are drawn to the sticky traps which capture and kill them (although this isn’t the kindest way of killing them!).
Gnats in houseplants, like most flying insects, are attracted to light, so fixing the sticky traps near sources of lights such as windows or lights allows you to capture the largest number of flies. You can also get sticky traps on wooden sticks, so you can stick them in the soil of your houseplants.
You can leave the sticky traps up for as long as needed and then dispose of them once all the flies in houseplants are dealt with
Vinegar Traps
This is possibly the best way of dealing with gnats in houseplants, plus you can do it home! To make your own, mix 2-3 drops of liquid dish soap with some white vinegar and pop the solution next to your houseplant(s). This attracts the gnats and they’ll fly into the liquid. Keep repeating this until all of the flies are gone, and soon your houseplants will be free from gnats!
Carnivorous Plants
If you want to go au natural, you may want to consider a carnivorous plant. Flycatchers will help reduce the number of these pests flying around in your air. They’re excellent at trapping fungus gnats, plus it gives them some extra protein to munch on. Yum.
The easy care Chinese Evergreen is low maintenance and therefore less often a victim of Gnats.
Chinese Evergreen 'Silver Bay'
Houseplant Fungus Identification
Fungus gnats (as their name suggests) love moist fungi rich environments. One way to prevent their unwanted arrival is through early house plant fungus identification. Quickly dealing with the infected plant will reduce the risk of it attracting gnats to come and lay eggs.
Root and Stem Rot
One of the main problems faced by houseplants is root and stem rot, caused by overwatering. Overwatering causes fungal mycelia to multiply rapidly and infect the plant. It’s easy to identify root and stem rot because it causes rotten patches at the base of the plant.
When a plant starts to show root and stem rot, in many cases, it is already too late because the whole of the root system will be infected. You can try to treat root and stem rot when there isn’t much, by cutting off the infected parts and treating the plant with an anti-fungicide.
Grey Mould
Grey mould is caused by airborne fungi that land on the plant and are identifiable by little grey patches of mould. If your plant is in dry conditions, it won’t be affected by this and is typically not a problem.
However, if your plant is in cool or humid conditions and you start to see brown dead patches on the plant, you need to cut away the dead and rotted parts and move the plant to a less humid environment.
Fungal Leaf Spots
Fungal leaf spots are easy to identify and treat. They show up as little brown spots on the leaves of your plant. The fungi that cause fungal leaf spots are most prevalent in cool and wet conditions, so removing the affected leaves and leaving your plant to dry out a little will generally solve the problem.
To prevent future occurrences of fungal leaf spots, try to avoid getting water on the plant’s foliage. Water in the morning as opposed to the evening, and decrease the amount of humidity in the plant’s environment as much as possible.
White Mould
White mould is fluffy white cotton looking stuff that you find on your houseplants’ soil. It grows when there isn’t much ventilation in the environment, like in winter when all the windows are closed. Thankfully white mould is completely harmless to you and your plant so you can just scoop it out.
Question Buster
Will gnats in houseplants go away on their own?
No, flies in houseplants reproduce at an extremely fast rate so if the problem is not dealt with immediately they will continue to multiply.
How long do fungus gnats live?
Gnats in houseplants spend the first 2 weeks (and the majority of their lives) as larvae, they are then in the pupae stage for 3-7 days, they are then adult fungus gnats for approximately 8 days.
In a nutshell
So here you have it! The best ways to identify and get rid of flies in houseplants. Generally speaking, the problems caused by fungi’, including flies in houseplants, can be prevented by keeping houseplants in a dry and warm environment. Of course, this is not always possible depending on our homes, but you can buy dehumidifiers that are reasonably priced and place them around your home to stop the air from becoming too moist.