How To Get Rid Of Houseplant Flies (Fungus Gnats) 5 Tips

How to get rid of houseplant flies? It’s a very common question for those of us who like to keep indoor plants. Houseplant flies aka fungus gnats actually pose more of a nuisance to us than our green friends. Apart from causing irritation, they can attract other bigger flies and insects, too. Such influxes of critters may cause a risk to our food, pets and eventually harm plants, too.

Houseplant flies can also make things look untidy – so, how do we get rid of these creatures for good?

Read on for some tips about how to tackle houseplant flies and deter them – and we’ll explain why most household spiders are our friends! 

What attracts flies to houseplants?

As you may imagine, colour and fragrance attract flies to houseplants. Some lay eggs on them, and hatchlings automatically begin feeding on the nearest food. Eggs and hatchlings may be carried into our homes from purchases we have made, too.

 Good examples include plants we purchase to add to our collection or to eat!

Some houseplant flies may be transported as adults, often hidden on undersides of leaves. They can also be well hidden as larvae or eggs in compost.

What are the little black flies on houseplants that I keep finding?

Chances are, the little black flies on houseplants that keep popping up are fungus gnats. These can be easily confused with fruit flies.

What’s the difference between fungus gnats and fruit flies?

Fungus gnats tend to nest and feed in the soil of potted plants. Whereas fruit flies are generally attracted to overripe fruit (hence the name!) or rotting food.

Identification can be difficult as they are so small but fruit flies are generally rounder like a smaller version of the common house fly whereas fungus gnats have longer bodies and dangling legs.

How to get rid of houseplant flies: 5 tried and tested methods!

Below are five methods that can definitely help in your battle against pesky fungus gnats. You can one or two individually all combine all five if the plant flies are proving to be stubborn!

Adjust your watering schedule

Believe it or not, one of the easiest ways to get rid of fungus gnats is to decrease your watering schedule. This can actually stunt larvae growth – be sure to check accordingly that you can decrease watering for specific plants before you go ahead.

Yellow sticky traps

houseplant flies (fungus gnats) stuck on a yellow sticky trap in a plant pot

Yellow sticky traps are also fantastic for getting rid of adult gnats. These tend to attract black flies thanks to their appealing colour. They’re easy to find on Amazon as well as in DIY shops and supermarkets. Remember, you’ll need to hang these up inside only – otherwise innocent butterflies might get caught!

Utilise Biological Control

Biological control is another option people consider when it comes to controlling gnat populations. This means introducing beetles, mites, or spiders to your plants that can keep fungus gnats down! You can, believe it or not, purchase these creatures online.

But aren’t spiders houseplant pests?

Hardly – as construction engineers, they are masters! Centuries ago, and until recent years, many people thought it unlucky to destroy webs indoors – and surely the best reason was because they killed off flies.

Spiders shouldn’t be considered pests. They might give you a fright every now and then, but they tend to do us a fantastic service. Some enjoy congregating around houseplants, though many will prefer to hide themselves away.

Therefore, introducing small spiders into your home can also deter houseplant flies to an extent. However, there are other ways around the problem, too.

Use chemicals to kill houseplant flies

Not always – specialist housefly cleaners are sometimes expensive, have a repugnant smell and don’t always do a thorough job. As mentioned, one of the best ways to tackle frequent gnat visitors is to cut down the population through adjusting your watering and care regime.

There are several types of chemicals you can use to kill houseplant flies. Many are ready mixed and will have the optimum strength. However, if you use too strong a mixture, you risk destroying part or all of the plant! When your houseplants are close to their neighbours, it’s best to move them further apart for treatment.

However, in many ways, it’s best to avoid using chemicals altogether. Some can be harmful for pets and aquatic life as well as for winged pests – so always make sure to use with caution.

Believe it or not, some people have come up with their own homemade blends of housefly killers that they swear by. Various accounts suggest a blend of apple cider vinegar and washing up liquid can work wonders – but if you do follow this route, as always, spray carefully!

Use concentrated oils rather than scented candles

Whilst you may confuse plant flies by burning floral or sweet scented candles or incense sticks, this will not kill them! They may keep their distance from burning sticks and candles – but can also be attracted by sweet smells. 

However, some concentrated oils repulse house flies. They can be expensive to buy, but when used sparingly, represent great value for money.

The best fragrances to repel flies with include peppermint, rosemary, lavender and lemongrass.

Are there any plants that repel flies?

venus fly trap

There aren’t any specific houseplants that repulse flies outright – but as you may already know, the Venus fly trap is a great asset in your fight against nuisance winged pests.

Fly traps don’t repulse plants, they attract them – then devour them! Great in a kitchen, they will add a pleasant leafy display but come into their own as fly extinguishers.

What are the most prevalent flies attracted to houseplants?

The most prevalent flies attracted to houseplants are aphids. These include whitefly and blackfly – and even the annoying greenfly you’ll find out in the garden. It only takes one open window for these greedy little mites to enter the house where they lay eggs!

However, as mentioned, fungus gnats also tend to be regular pests around popular houseplants. Finding tiny flies on house plants is also pretty common during the warmer months.

Can I check houseplants for signs of pests before I buy?

Yes, to some degree you certainly can check plants before purchase. This is only really possible by checking the exterior – and do remember that some insects may be on the underside of leaves or petals.

If you are buying plants encased in cellophane, check to see if there are any flies towards the base of the plant, or stuck to the cellophane. If able, drag a finger across the surface of a growing medium. If you see larvae or clusters of eggs, it’s likely the whole batch on display will have been affected.

When plants are cultivated together en masse, it’s typical that they share the same problems – this happens especially when multiple plants are sold in the same tray. Therefore, if one plant shows signs of fly distress, it’s likely the whole batch will, too!

How do I check if my houseplants have been attacked by flies?

Warped buds and leaves are good indicators that something is wrong with your plant. Leaves should look fresh, firm and clean. Sometimes, a particularly shiny spot on a leaf or leaves is evidence a plant has been attacked.

You may nip off that leaf in the first instance – but it’s a good idea to rigorously check the plant completely when you get it home, before placing it near to others. If you see evidence of nibbled leaves, it may mean you have a fly infestation.

Conclusion: how to get rid of indoor plant flies?

Unfortunately, indoor plant flies are facts of life for those of us who cultivate greenery indoors! Small flies in house plants are sadly common – but knowing how to get rid of plant flies doesn’t take much swotting up.

Keep a close eye on your watering regime, and be sure to consider the suggested non-chemical methods of resistance first. Your pets – and other plants – will thank you!