Harvesting indoors gardens is highly rewarding especially you planted them from scratch.  However, sometimes the joys are disturbed by pests. They don’t care about your excitement in gardening. All they can do is to spoil your joy and they are one of the most annoying indoors pests. You need to know how to get rid of fungus gnats because they are dangerous for your garden since they eat your plants.

These pests can disturb your seedlings. Even though they are harmless to human, the gnats can be disturbing. They tend to fly around in numbers and sometimes flying right in front of your face. They can be found in your indoor garden and are attracted with high humidity and moisture in the garden.


Fungus gnats are also called Sciarid Fly, a predatory insect. Fungus gnats are different with fruit flies. They mostly found in indoor gardens disturbing the plants. They are also different in color compared to fruit flies. Fungus gnats are darker on their head. Fruit flies are found on rotten fruits while fungus gnats found in a damp soil, or sewer. Fungus gnats can fly straight to human faces because they attracted do CO2 and of course, it is so annoying.

The adults are not the most annoying to plants because it is the fungus gnats in larvae form that can cause more damage to the plant. The larvae are ¼ inch long and have shiny black color and they are eating machines. They feed on the root hairs well hidden and it makes your plants’ leaves yellow. They also make the plants look wilting, poor growth loss their vigor and eventually when they eat the plant root system, you will lose your plants, meaning die. They can also dig tunnels into your succulents, onion seedlings or leeks which eventually will become worst to these plants.

Meanwhile, the adult fungus gnats are about 1/8 inch long. They have long legs and thin antennae. They more look like tiny mosquitoes than flies. Fungus gnats love the damp and moist soil and they seek these soil to lay their eggs. The eggs are laid in a cluster with length about 1/100 inch. These insects infest into your plant starting from wet algae areas in the garden. Then, they will fly in short distances to locate plants with wet soil.

The adults only live for one week and can lay 300 eggs on moist soil. After four to six days, tiny larvae emerge and starting to consume the plant roots after they are two weeks old. The pupa stage only last for three to four days. Then, the young adults will start to leave the soil. So, the life cycle of fungus gnats from eggs to adult takes three to four weeks. It is dependent on the temperature on where they live.

Even though their live cycle seems short, they can lay multiple generations of fungus gnats at once. At most, your plant can be eaten by 20,000 larvae. The plants that are prone to injury caused by the insects are Geraniums, African violets, Carnations, and Poinsettias.

So, how do we know when there’s fungus gnats infestation? You will know when you see a plenty of small flies on the surface of the medium or right on the surface the plant. The flying fungus gnats will fly away when disturbed. You should look for the larvae at the root of the plants to know whether there is already infestation going on.

15 Ways on How to Get Rid of Fungus Gnats

They are dangerous but you can rest assured because the fungus gnats can be getting rid of without harming your plant. These are safe ways on how to get rid of them:

1. Watering

Take a good attention to your plant watering. Overwatering will attract the gnats since the soil becomes more moist and damp. They can find food supply such as algae in the moist and damp soil. By keeping the soil dry between your watering schedules will make the fungus gnats less attracted to the plant since dry soil have less food supply for fungus gnats and they also cannot lay eggs on the hard dry soil.

The tips are to try to hold your watering until the soil dry for one to two inches. Then, take a more attention in winter because, in this time, you tend to use plant less than usual. An advice for potting, avoid water holding pot like peat moss. this kind of pot is more attractive to fungus gnats since it holds water.

Please note that you should remove fallen leaves around your plants because these leaves can keep the soil moist and it also a food source for gnats.

2. Use Sand to Controls Larvae

Adult gnats lay eggs about 1/4 inch top in the moist soil. So, besides controlling the watering to keep this part of soil dry, you can also put some sand on this part. First, it will drain quickly, and then it makes the adult gnats think that the soil is dry so they won’t be attracted to settle. Applying sand is also fun because you can decorate them with colored sand to make your indoor garden looks nicer.

3. Apply Vinegar to Control Adults

Basically, this is a fungus gnats trap. It also can be used as a trap to other insects. Mix apple cider vinegar or cheap beers with soap in a jar. Then put the jar in the strategic places where the fungus gnats infested. Just like the most insect, they will be attracted to the vinegar and then drown as they tempted to taste it. You can reuse the vinegar as you control the gnats population.

4. Use Potato Slices to Control The Larvae

This method is to attract the larvae. Slice the potato into tiny slices. Then, put them right next to the gnats infestation and leave it approximately for 4 hours. The potatoes will attract the larvae and the adult itself. You will find the larvae under the potatoes and can take control over their population. Replace the potatoes until you can get rid of the larvae.

5. Use Sticky Traps to Controls The Adult Gnats

You can buy the sticky traps to trap the flying gnats. On the other hands, you can also make a homemade sticky trap. All you need are vaseline or tanglefoot on a reasonably wide cardstock. Place the card horizontally or vertically right above the gnats infestation. It will catch the flying gnats. Keep replacing it with a new one as the traps become full of dead trapped fungus gnats. Find a yellow cardstock as the gnats are more attracted to yellow.

6. Use Food Grade Diatomaceous Earth to Control The Larvae

Diatomaceous earth is one of the most effective treatments for getting rid of insects. It is also environmentally friendly. Make sure you are not getting a pool grade diatomaceous earth because this variant is not good to be applied to food gardens and pets.

Always wear a dust mask when applying the DE because you don’t want to inhale the dust. It contains microscopic silica that can shred insects’ body. The insects will feel like suffering from sharp glasses when in contact with the DE.

So how to apply this method to get rid of gnats? You can mix the top of your plant soil. Even more, you can also mix the entire soil with the DE. This method will kill the larvae which hide in the soil. However, make sure that you don’t apply this in your worm bin because it will kill them. You can buy the diatomaceous earth online.

7. Use Bacillus Thuringiensis (BT) to Control Larvae

Bacillus Thuringiensis (BT) is a bacterium that can kill many types of small creatures like worm, larvae, and insects. For killing fungus gnats, you need to find BT variant called israelensis or Bt-i. Israelensis BT is also called H-14. You may found that this variant is also sold under various brands such as Gnatrol or Knock-out Gnats. You can tell that this Bt-i variant is special to combat gnats. All you need to do is apply it to the gnats’ infestation. Bt-i will kill all of the gnats effectively. However, it is quite pricey, but worth it. You can buy them online.

8. Use Beneficial Nematodes to Controls The Larvae

As you may know, gnats larvae are the one who is dangerous to your plants. That’s why most of the chemical is specifically target the larvae. In this method, you will use a type of nematode called Steinernema feltiae. It can drench the soil when watering. The tiny worm will enter the fungus gnats larvae and then release a bacterium that is lethal to them.

The nematodes are expensive so it will be effective if you buy and use it for large infestation because they can also kill various soil pests. Different from diatomaceous earth, the nematode is safe to use in the worm bin.

9. Use Hydrogen Peroxide to Controls The Larvae

Besides it is useful to get rid of the underarm odor, hydrogen peroxide is also useful in getting rid of gnats. Mix hydrogen peroxide with water with ratio 1:4. Appy this method when the soil is dry and then pour it into it. The larvae will eventually die when touching the peroxide. It is safe because the hydrogen peroxide will turn into harmless oxygen and water after this method. You can repeat this until you gain control over the gnats population.

10. Use Chamomile Tea to Control Damping Off

Gnats do not only bring their dangerous larvae to your plant. They also bring some friend that can cause damping off. Maybe this method won’t affect the fungus gnats, but chamomile tea will prevent damping off. Simply mix the chamomile tea with water in your watering containment. Water your plants with this mix and let it does its job.

11. Use Cinnamon to Control The Larvae

Different from the chamomile tea, cinnamon powder can affect gnats’ larvae and also stop damping off. It is a natural fungicide that is also can prevent damping off. It will kill the fungus gnats and their larvae. However, you need to use Ceylon cinnamon or Cinnamomum verum because these variants that truly work.

All you need to do is sprinkle the cinnamon to the top layer of soil. Repeat it until you get rid of the gnats. However, cinnamon kills worm so you don’t want to apply it to your worm bin.

Cinnamon can be combined with peppermint and sesame oil. Apply it with a spray bottle to kill the flying fungus gnats.

12. Use Tanlin

Tanlin is fungus gnats biological control. It also called CX Hydroponics Tanlin. Apply it to strategic areas where you can find the larvae. You need them to eat the Tanlin. Tanlin will make them swell up if the larvae eat them. The downside is that Tanlin does not affect adult fungus gnats.

13. Use Rubbing Alcohol Spray

Spray a mix of rubbing alcohol and water to the plant and the soil. You need to mix one cup of the alcohol and a liter of water to do this. However, you need to test on a sheet before applying the mixture to know whether the mixture is not too hard on the plants. For optimum result, apply this every three days for two weeks.

14. Use Thin Layer of Cigarettes

Nicotine can be used to get rid of fungus gnats since it is a repulsive substance. All you need to do is to shred the cigarettes and sprinkle them to the top layer of the soil. Make sure you dispose of the filter since it takes a long time to decompose. You should also make sure that you don’t apply this method to a herbal and eaten plant.

15. Use Soap Spray

Soap can get rid of fungus gnats. All you need to do are mix lemon dish detergent with water. Then, soak the plant and the soil where the larvae found. You will need to rinse the leaves with clean water after one hour.

Let us know if you have other tips on how to get rid of fungus gnats.