How to keep gnats out of house plants: easy tips

Ever since the pandemic started, a lot of people had a sudden obsession with house plants. From being a simple past time, ‘plant parenthood’ is now a big thing. Plants are nice to look at, but if you zoom in, you might discover the presence of gnats. These insects feed on organic soil matter and even chew plant roots. With this, you should know how to keep gnats out of house plants to protect your precious potted babies.

What are gnats?

When it comes to plant pests, you need to know what you’re dealing with. Gnats, for one, are small flies with two wings. It shares the same appearance as mosquitoes, and they can also bite humans.

However, the main threat of gnats is on house plants. These tiny flies lay their eggs on the soil, hatching, and feeding on the organic matter. As the larvae grow, it will suck nutrients from the soil and damage the plant roots. Over time, gnats will dry out your plant and cause death.

While gnats are common problems to greenhouses and farms, it can also infest in a home setting. They can congregate in large numbers underneath the soil. This means they can cause damage without being seen.

If your plant is wilting despite receiving ample sunlight and water, you should consider the possibility of gnat infestation. You have to do something to eliminate the pest and save other plants from being infected.

Take note that gnats thrive in moist conditions, which is why potted plants are a perfect environment. They also feed on decaying vegetation, like the dead leaves that you let rot at the pot. While it can be tricky to stop these pests, below are the things you can do.

How to spot gnats in your house plants?

At first, gnats may appear harmless, small insects. This is the same reason that allows them to infest house plants until it dies.

Take note that it’s easy to mistake gnats with fruit flies because they infest the same thing. However, gnats tend to have a black color, similar to mosquitoes. On the other hand, fruit flies have lighter, orangey color.

Both of these insect pests are small at around 1/16″. Since they are small, it’s easy to dismiss their presence or spot an infestation on a plant.

Usually, gnats come from newly purchased plants or potting mix. If your house plant doesn’t have any gnats before bringing it indoors, an open window might have brought the pest inside.

Moreover, gnat larvae have shiny black heads with elongated whitish bodies. You will notice slime trails at the top of the soil, similar to snails. This is usually a tell-tale sign of gnat infestation.

Aside from that, gnats are attracted to light. You may see some by your window or anywhere with a prominent source of light.

House plants
Photo by Pixabay

How to keep gnats out of indoor plants?

Are you wondering how to kill bugs in houseplant soil? It may appear tricky at first, but the following are some workarounds you can make to get rid of the pest:

  • Utilize sticky traps

One of the easiest ways to reduce the gnat population indoors is to utilize sticky traps. You can buy it from most gardening shops or supermarkets, so it’s an easy solution.

To use the sticky traps, press the sticky side right into the top of the soil. This will pick up the gnats that are on the move. It can also remove larvae on the surface. Use yellow traps to attract more gnats into it for more efficient removal.

You can also place sticky traps near your windows where the gnats tend to enter. This will help catch those that are about to reach your house plants.

  • Make a DIY vinegar trap

Another effective way to catch the gnats is through the use of a DIY vinegar trap. Simply mix equal parts of vinegar and cider on a shallow dish to spread out as much solution as possible. Place this near the affected house plant and wait until the gnats drop on it.

Gnats will be attracted to the vinegar solution and land its way to death. You will need to replace the solution once it has been filled with gnats. Also, never pour the vinegar into the house plant since it’s highly acidic and will kill the foliage.

  • Go easy with watering

Another way to reduce the gnats’ population on your house plant is to be modest with watering. Avoid over-watering the soil since it’s the main reason why gnats thrive on the pot. By depriving the gnats with excess moisture, adult ones are less likely to lay eggs on it.

Aside from discouraging the laying of eggs, preventing excess moisture will also disrupt the larvae’s growth. It will lead to their eventual death, which will solve the problem in a matter of days.

  • Introduce nematodes

Beneficial nematodes are widely used in gardening to kill a slew of soil-harboring pests. From termites to gnats, nematodes are efficient and safe.

Nematodes can be purchased commercially and diluted on water. You will use the nematode solution to water your plants. In turn, the live nematodes will feed on the gnats larvae and other pests.

The beauty of beneficial nematodes is it will not become a pest of its own on your plants. It will die once there is no pest to eat.

However, you must administer beneficial nematodes at a dark place because the microorganisms are sensitive to light. It can easily die in light and heat exposure, so you must have a controlled environment.

It would take several applications to remove all the gnats on your house plants. If you have any leftover nematode solution, keep it in an opaque bottle and away from intense temperatures.

  • Apply some hydrogen peroxide

If you bought a potting mix, I suggest treating it with hydrogen peroxide first. This will kill any gnat larvae harboring on the soil. It will also prevent the gnats from transferring into your house plants.

Gnats will die upon contact with hydrogen peroxide. Just make sure that you dilute the hydrogen peroxide in water with 4:1 proportion.

  • Dilute some neem oil

You can also use diluted neem oil to kill the gnats on your house plant in some cases. Make sure that you dilute the neem oil in water since its pure form can kill plants.

However, you have to be careful in applying this solution as neem oil poses harm to some plants. If in doubt, I suggest trying safer alternatives here.

  • Utilize pyrethrin

A pyrethrin is a form of insecticide that works by contact. It dehydrates the pest or alters its nervous system. As much as it’s harsh toward gnats, pyrethrin is safe for plants and will break down organically once its job is done. You can also use this on vegetable plants without worrying about the toxicity to humans. Pyrethrin doesn’t persist in the soil and can be removed through the foliage by proper washing.

How to prevent gnats on your house plants

House gnats are pesky, but there’s a way to prevent it from ruining your house plants. The following are some of the things you can do to stop these pests on their tracks:

  • Mind the pot’s drainage

As I mentioned earlier, gnats harbor on potted soil with excessive moisture due to poor drainage. Aside from watering properly, you can also use a dehumidifier to remove the soil’s excess moisture. If the room is too humid for your house plant, move it and look for some sunlight where the soil can dry.

  • Use well-draining soil

One of the best ways to prevent gnats is to use the right oil. Look for a well-draining potting mix so it won’t harbor too much moisture. I also recommend using slow-decaying organic matter like coconut fiber or carbonized rice husk. This will prevent gnats from congregating since food isn’t readily available. Also, you should avoid reusing soil if you’re transferring the plant to a new pot.

  • Prune and dispose

If your plants have decaying leaves, prune it out and dispose of it. Don’t let it rot on the pot because it will only attract gnats into your potted house plants. As much as possible, you should limit any decaying matter in and around your potted plants because it’s the leading gnat magnet.

  • Cover the soil

One trick you can do to block the gnats is to smother the soil. You can use pebbles to cover the top soil so gnats won’t get the chance to lay their eggs on it. A layer of gravel and coarse sand are also good choices since these materials drain well. Even if there are already larvae beneath, it will die due to the suffocation. The bonus part is that this top soil cover looks excellent and aesthetic for house plants.

  • Repot and sanitize

After purchasing the plants, you must repot the plant and remove the old soil. You should also sanitize the potting mix you’re going to use by using diluted hydrogen peroxide. It’s also important to disinfect the pot where you’re going to transfer your plants.

  • Consider carnivorous plants

Aside from the other tips I recommend above, you can also consider having a carnivorous plant like fly traps. This will help combat the gnat population in your home. It’s also a unique house plant! Just make sure that you cover the carnivorous plants’ top soil so gnats won’t invade it.

Frequently Asked Questions

Q: What attracts gnats in my home?

A: Gnats are usually attracted to fresh flowers and other unsealed produce. These insects also gravitate toward food spills and other organic matter where it can feed and lay eggs. As much as possible, don’t leave your kitchen dirty because it will only attract more pests like rodents, roaches, and gnats.

Q: What smell do gnats hate?

A: Some suggest that gnats hate the smell of vanilla. You can use this to repel gnats from your house plants, but make sure that the product you’re using won’t kill your potted greenery. You can also try other alternatives if vanilla isn’t safe for your plants.

Q: Do gnats go away at night?

A: It’s true that gnats are more active during the day, but they are still around at night. Still, it doesn’t mean that gnats won’t damage your plants at night. Once they have laid their eggs on the potted soil, the larvae will continue damaging your plants and stealing nutrients.

Q: Do gnats go away on their own?

A: Most of the time, gnats go away during summer due to the dryness. Also, gnats have short life cycles that often last from mid-May to the last weeks of June. While they will not pose serious harm to humans, this pest can kill plants at home.

Q: Where do gnats come from in my bedroom?

A: Gnats are attracted to specific scents and food like banana and any rotting organic matter. If you have an unemptied trash bin in your bedroom, it’s possible that gnats are attracted to it. If you’re worried about your potted plants, you can try the tips we discussed above to drive away or kill the pest.

Q: Does cinnamon kill gnats?

A: Cinnamon is popular as a natural fungicide. It can help in controlling gnats, but it may not be suitable for all plant types. You should perform some research first before dumping cinnamon on your house plants. If in doubt, you can explore other options here to prevent damages to your plants and for guaranteed results.

Final words

Knowing how to keep gnats out of house plants is important, so your indoor foliage won’t be damaged by pests. Being proactive is key so that gnats won’t access the soil. Above, I shared some preventive tips as well as solutions if gnats are already attacking your plants.

What do you think of the points above? Do you have personal tips to share? Drop it below in the comment section!

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