Fungus gnats are bugs that resemble mosquitoes and prefer moist potting soil.
Houseplants with gnats are a pain. They are tiny flies, or “fungus gnats,” approximately 1/8 of an inch long, that are lured to the moist potting soil and decomposing plant matter at the bases of indoor plants. They don’t bite, despite having a mosquito-like appearance.
The simplest strategy to stop gnats from taking over your home is to avoid over-watering in the first place, as gnats in houseplants often come from the potting mix containing too much moisture. But what if the harm has already been done and your plants are being surrounded by a swarm of bothersome flies? Here, we’ll go over the most effective methods for getting rid of gnats in indoor plants.
How to identify gnats in indoor plants
You can check for gnat eggs to see whether you’re about to encounter an issue. In the soil, fungus gnats lay their eggs, which develop into larvae that eat fungi in plant soil. The larvae of the fungus gnat are about 1/4 inch long, with a shiny black head and an elongated, translucent to whitish body.
They enjoy organic stuff in addition to fungi and may occasionally consume plant roots or seedlings, which will make the plant appear wilted. Inspect the area for a slime trail similar to the ones that slugs and snails leave. Your indoor plants most certainly have gnats if you can see a trail.
Gnats also enjoy light, so you might see them on your windows, especially if there are any indoor plants close by.
Even though the ordinary fruit fly and gnats are completely distinct insects, they are frequently confused. Fruit flies, unlike fungus gnats, are tan in color and resemble oval, baby house flies. They tend to hang around near fruit.
How can I eradicate gnats from my indoor plants?
We plant lovers don’t want to witness plants being harmed by pests. The problem enters our homes, which is gross, therefore we especially don’t want to see pests in our houseplants! Fungus gnats are pesky, winged insects with little wings that resemble mosquitoes and are about the size of fruit flies. The good news is that compared to many other pests, these plant flies cause significantly less harm, and even better, they’re rather simple to get rid of.
Long legs, transparent wings, and a preference for nutrient-rich, damp soils are characteristics of fungus gnats. These little flies may be seen flying around plant containers, but unlike some more dangerous pests, you won’t observe them actually chewing on the plant’s foliage. However, you will see them in the soil, feeding on the organic matter and hairs from plant roots. Do not underestimate the damage that these bugs can still do if not addressed.
Even though adult fungus gnats only live for about a week, they can have a big impact in that short time by producing up to 300 eggs under the correct circumstances. With such a quick turnaround and a brief life cycle of about 3–4 weeks, populations can grow incredibly quickly.
It’s rather simple to tell if your plant has a fungus gnat issue. Since these plant flies can’t fly very well, they usually stay rather near to the plant. They’ll probably be moving in zigzag patterns while you watch them. It’s typical to witness all the different phases of this bug at once because they reproduce so quickly. It’s likely that some bugs still in their larval stage will be visible if you gently agitate the soil. They inhabit the earth where they eat organic debris and have translucent bodies and glossy, black heads.
Our plants are getting ready to settle in for the upcoming cold season as winter approaches here in North Dakota. Unfortunately, that signals that these pesky bug populations are about to reach their peak. During this time, dormant plants use less water, which causes their soil to stay moist for longer. Gnats thrive in moist soils because they promote root rot and fungus. Be cautious when bringing delicate plants inside to overwinter since you run the risk of inviting unwelcome pests into your house.
Your plants will start to exhibit signs of stress if ignored and neglected. Fungus gnats don’t directly harm plant leaves, but they eat the root hairs and deplete the soil of vital minerals. This may result in abrupt plant withering and yellowing of the leaves, sluggish development, and a general decline in vigor.
When tackling any pest, you should always start with natural management approaches. The least hazardous and disruptive to your plant and house are typically natural and organic remedies, while chemicals may occasionally be required as a second line of defense. Fortunately, most fungus gnat populations may be controlled and eliminated naturally provided they are discovered and dealt with in a timely manner. Remember that one plant container can hold three to four generations of bugs, so you’ll probably need to apply your favorite approach more than once. Gnats in your indoor plants can be managed in the following ways:
Do not overwater. Before watering your indoor plants, allow the top couple of inches of soil to dry up. This will not only stop fungus gnats from deciding that your plant would make the best place for them to live, but it will also interfere with their reproductive cycle and assist to reduce populations that have already moved in.
Activate sticky traps. Not just for mice, either! Sticky traps are easy fixes for many pest issues. Gnats that are moving will be caught if you place them immediately on the soil’s surface. To stop them from laying eggs, remove them from the trap, discard them, and replace it frequently (every two to three days). Particularly effective at drawing these insects, yellow traps are.
Create vinegar and cider traps.
Mix equal volumes of cider and vinegar in a shallow dish or can to act as a trap for fruit flies. Lay the trap on the soil surface inside the container or even next to the damaged plant. The concoction will attract the bugs, who will then fall into it and drown.
Bring in useful nematodes. Although it may seem counterproductive to introduce additional bugs into the equation, doing so is a simple way to reduce pest numbers. Nematodes are incredibly minute, worm-like insects that are frequently invisible to the unaided eye. In their larval stage, they attempt to infiltrate fungus gnats and other insects, releasing a bacteria that eventually consumes the pest from the inside out. When you think about it, it’s awful and disgusting, but not as disgusting as allowing gnats to devour your prized houseplants!
If all else fails, there are always insecticidal goods and sprays to keep pest numbers under control. There are many products available that either target the adult stage or the larval stage, but either is OK. You should be able to get rid of these unpleasant plant flies in a few of weeks as long as you successfully target one phase of their life cycle and reapply often.
Larvae are easily eliminated with hydrogen peroxide since it kills them immediately upon contact. Infuse your soil with a solution made of four parts water and one part hydrogen peroxide.
To destroy larvae, neem oil can also be put to the soil after being diluted with water. Neem oil can also be sprayed on surfaces to instantly kill adult flies. Last but not least, pyrethrin sprays contain extracts that are harmful to a variety of pests and can instantly kill flies and fungus gnat larvae.
Fungus gnats can affect the health of your houseplants even though they don’t carry any diseases that are dangerous to humans. Your plants will thank you by giving off a lush, healthy appearance to enliven your home if you keep pests at away.
Why do gnats flock to my house plants?
Because of this, you might have noticed much smaller flying insects buzzing around your houseplants and mistaken them for common or garden fruit flies, but the more likely species is fungus gnats.
Soil gnats is another name for these little flying insects. In the potting soil of indoor plants, they thrive and reproduce.
Therefore, if you see little black gnats flying around or crawling through the dirt around your houseplants, they are most likely fungus gnats.
Fungus Gnats Are Part Of A Family Of Insects That Include:
- Bolitophilidae
- Ditomyiidae
- Keroplatidae
- Diptera
- Diadocidiidae
They typically eat mushrooms and dead plant detritus and are naturally found in moist forest environments.
Small Pests
Fruit flies are much larger than fungus gnats, which are considerably smaller. In actuality, they only reach a length of around a quarter inch.
Therefore, despite your incorrect belief that they are too small to do any real harm, their larvae may and will harm your indoor plants.
Fungus Gnats Like Warm Moist Soil
Fungus gnats are frequently drawn to indoor plants because they lay their eggs in damp soil.
When the eggs hatch, the young birds will eat roots, algae, fungi, and other organic matter like potting soil.
Fungus gnats are generally innocuous as adults, but the larvae can destroy your houseplants.
The larvae, as we have seen, are the ones that cause the greatest harm because they may feed on plant roots that are buried in the soil, which can cause damage to the roots and stunted growth.
A fungus gnat is most likely what you are witnessing if you notice tiny black gnats flying or crawling about in the dirt surrounding your houseplants.
Where can I find gnat-free potting soil?
If you have a lot of indoor plants, it might be challenging to get rid of fungus gnats. The adults can effortlessly fly or leap from one plant to another, depositing their eggs in any location with moist soil.
The adult fungus gnats have a short lifespan, similar to fruit flies. Therefore, your fungus gnat problem will be solved once all the larvae have died.
Fungus gnats can be readily controlled without the use of dangerous synthetic pesticides by adopting natural pest control solutions and techniques. The greatest ways to get rid of those pesky flying gnats from your indoor plants are listed below.
Control soil moisture
Therefore, avoiding overwatering your plants is the simplest and most efficient way to control plant gnats and ultimately get rid of fungus gnats.
On most indoor plants, though, you don’t want to let the soil entirely dry up. To keep the ideal moisture level for your houseplants and get rid of gnats in plant soil, use a soil moisture sensor.
Indoor plant watering tools also make it simpler to water houseplants and aid in preventing overwatering, which will help you get rid of plant gnats.
Water plants from the bottom
When you water plants from the top, the top inch of the soil, where fungus gnat larvae typically dwell, tends to stay rather damp.
Without endangering the plant’s general health, bottom watering plants will make it simpler to maintain drier top soil.
Simply pour water into the plant’s drip tray or storage pot to water it from the bottom, and the plant will absorb the liquid through the drainage holes.
Never let your plant sit in water for an extended period of time. After soaking for around 30 minutes, drain out any extra water.
Use yellow houseplant sticky stakes
A very safe technique of pest control is to place a yellow sticky trap next to the plant. This will draw and catch the adult fungus gnats.
This will only work to control the adult population; it won’t address the root cause of the issue (the larvae).
However, yellow sticky traps unquestionably assist in preventing adult fungus gnats from flying to other plants.
Apply organic pest control products
To get rid of gnats in potted plants, pour or spritz an organic insecticidal soap or a neem oil mixture into the top of the soil.
I mix 1 tsp of mild liquid soap with 1 liter of water to produce my own insecticidal soap.
Neem oil has a lasting effect that aids in prevention and is excellent at killing pests that attack indoor plants. Neem oil can be purchased here.
After a few applications, these organic gnat pesticides ought to work; just be careful not to overwater your plants.
Will gnats disappear if the soil is changed?
Place the affected plant in a different location for 1 to 2 weeks to prevent the infection of other plants if you discover that fungus gnats have infested one of your plants. This should also be done with new plants before you introduce them to the rest of your plants, just to be safe.
Getting rid of the gnat larvae can be done successfully by repotting. Place the plant in fresh, clean potting soil after thoroughly cleaning the pot. The moist soil, decaying plant matter, and rotting roots that fungus gnats so enjoy will all be gone.
To draw the fungus gnats to a plant, place a saucer of wine nearby. Funny enough, wine is far more enticing to fungus gnats than soil. They immediately jump in, and well, you can probably guess what happens next.
Over the soil in the pot, strew a layer of sand. The gnats find it considerably more difficult to lay their eggs in firm sand.
Two tablespoons of cinnamon are added to a liter of boiling water. After it has cooled, use it to water your plants. Gnats detest it, too!
Place yellow traps or sticky paper close to your plants. The gnats will fly directly in its direction and become stuck! Issue is resolved.
With a few matches, you can get rid of gnats without igniting your plant. Instead, place the head of the matches in the ground. The sulfur will immediately turn them off.
Did you know that small black fungus gnats are a favorite food of carnivorous plants? Watch a Sundew eliminate the flies by placing it close to the diseased plants.
Do you know of any further tried-and-true methods for removing fungus gnats, or any plants that have endured these troublesome insects? Use #thejoyofplants to share your experience with us on Facebook or Instagram.
Should I discard the gnat-infested soil?
Gnats are annoying because they dare you to capture them as they dart around silently and frequently within a few inches of your face. The fungus gnat, however, can be the most annoying insect of all if you love plants. Fungus gnats can grow quickly in indoor plants and lay their larvae in the potting mix’s top layer, even though they are safe to people. During the winter, these bothersome gnats might be transported within from outside plants. But more often than not, they come into your house on sick plants you brought home from the nursery or garden center. They enjoy hiding in extremely soggy soil that is rich in decomposing plant materials. Once established in one plant, they simply move on to other ones close by, where their larvae contentedly await birth in the first inch or two of soil. The main source of nutrition for larvae is fungi found in the soil, but they can also consume root hairs. The infestation keeps expanding as a result of the adults producing eggs and proliferating. But don’t worry; you won’t have to throw out any of your plants to get rid of fungus gnats. Allowing the soil of afflicted plants to totally dry out will kill the larvae if the infestation is new. However, if the infestation is getting worse, you’ll need to take more drastic measures. Sticky paper might be used to catch the adult fungus gnats, but the larvae that are laying eggs won’t be destroyed. I’ve discovered a simple, secure two-step home fix (sidebar, right) that completely solves the issue. Sand, many tiny saucers, and a delicious, fruity beverage—for the bugs, not you—are all that are required.
Steps to gnat-free
First, construct the sand trap. Get rid of the already-hatched larvae by gathering all affected houseplants and removing the top 2 inches of potting soil. The dirt should be thrown away right away, and its top layer should be replaced with sand instead, which dries up rapidly, is organic-free, and is not a good spot for fungus-gnat eggs to hatch. Before the following watering, allow the soil below to totally dry out. This should destroy all fungus-gnat larvae present and stop the laying of fresh eggs.
Set up the open bar in step two. It is simple to entice and drown adult fungus gnats using any sweet liquid that has a decaying odor. One of the most effective and affordable fungus-gnat lures I’ve discovered is a lovely $2 bottle of alcohol-free wine from Trader Joe’s. Place a tiny saucer with the liquid in it next to a previously affected plant (or by all infected plants if the infestation is already rampant). You should wake up to a disconcertingly pleasant collection of dead fungus gnats floating in the liquid if you let it sit overnight. The saucers should be discarded and refilled until no adult gnats are seen.