What Attracts Gnats: How To Eliminate and Prevent Infestation

There are few things more annoying than the sound of a fly buzzing around your head, but gnats are one of them. These tiny flies seem to always appear in swarms, flying around your head and getting into everything.

The risk of running into gnats is always there, but you might have noticed them appearing more often in your houseplants. While the problem is most common in summer, gnats can appear at any point in the year if conditions are right, so let’s look at what attracts them and what you can do about it.

fungus gnats on a sticky cardPin

What Attracts Gnats?

Gnats are most commonly attracted by the presence of water, although many other factors are also involved.

Different kinds of gnats will be attracted by slightly different things.

Three Common Gnats And What Causes Them

Let’s look at three common varieties to see what can draw specific gnats.

Each of these will hang out around your plants but can be caused by different factors.

Drain Flies

The drain fly (family Psychodidae) is a type of fly that looks a lot like a tiny moth.

They get their name because they’re often seen crawling out of drains where their larvae feed on bacteria caused by stagnant water or sewage pools.

And that’s what can also attract them to your plants.

When you overwater a houseplant, the soggy water can become infected with fungi and other contaminants.

Drain moths will be drawn to the soggy soil, where they’ll lay their eggs so their young can feed on the contaminants in the soil.

Fruit Flies

Fruit flies (family Drosophilidae) are one of nature’s cleanup crews and will flock to anything that smells like decay. This can include dirty dishes, spills, and rotting fruit in the kitchen.

However, overwatered plants can also attract fruit flies, as the water may leave a scum layer in which mold forms. They can also be attracted to plants suffering from rot or similar diseases, especially succulents. To the fruit fly, these are the perfect conditions for feeding their young.

Fungus Gnats

Of all the types of gnats, the fungus gnat (belonging to several families in the order Diptera) is most commonly associated with plant infestations.

As the name suggests, these flies’ larvae feed primarily off fungus. The larvae are often found in overwatered soil, where they feed off mold and fungal spores.

However, they are also known to chew on plant roots while searching for their preferred food.

It should be noted that certain plants attract fungus gnats naturally and use them as pollinators.

The Common Factor

As you can see, each of these different kinds of gnats has slightly different things that attract them, but the single most common factors are moisture and decay.

Thus, when you see gnats hanging around your houseplants, your first instinct should be to check the plant for signs of rot, infection, or overwatering.

It’s not uncommon for the presence of gnats to serve as a warning sign that something’s wrong with plants, sometimes saving the plant’s life.

Ways To Eliminate Gnats

So now that you know why the gnats are there, how do you get rid of them?

The first order of business is to eliminate the gnats and their larvae, which may require some very different tactics.

Adult gnats won’t live very long, and you can usually kill them with a simple vinegar trap.

Here’s what you need to do:

  • Take an empty soda bottle (the 20-ounce ones are perfect) and cut the top off where it begins to curve inwards.
  • Turn this section upside down, so it forms a funnel, and tape it, so the cut edges of the funnel and bottle are flush.
  • Now pour 1” inch apple cider vinegar into the trap and set it near your infested plants.

The gnats (especially fruit flies) will climb into the bottle to get to the sweet-smelling vinegar and be unable to escape, eventually drowning.

Fly strips or sticky traps also work very well against these airborne pests. As for the larvae, the best remedy is a neem soil soak.

This consists of an emulsion (1 teaspoon of Dawn dish liquid or pure castile soap added to either a quart or gallon of water) in which 1 teaspoon of 100% percent pure cold-pressed neem oil is added per quart (or 2 tablespoons per gallon) is mixed in.

Test a tiny portion of the plant 24 hours before use to ensure there are no sensitivity issues or allergies with the plant.

Use the neem in place of regular water when you water the plant.

The active ingredients in the neem will kill the larvae and protect the plant from biting or chewing pests for up to 22 days.

Ways To Prevent Gnats

Of course, the best way to get rid of gnats is not to have them at all.

  • During the summer, ensure all open doors or windows are properly screened, and practice exclusionary maintenance (such as caulking around doors and windows).
  • Make sure you keep your home clean and fix any leaks in the kitchen or bathroom.
  • Check your plants regularly for any signs of disease or infestation. But most importantly, practice good watering techniques.
  • Never use a calendar to tell you when to water a plant. Instead of letting the soil itself tell you.
  • Research how many inches down the soil needs to be dry before watering.

You can use the finger trick to test the moisture levels by simply sticking your finger straight down into the soil.

From the tip of your finger to each knuckle is approximately 1” inch, so you have a 3” inch, moisture-sensitive ruler on hand (literally) at all times.

For plants with thick growth that completely obscure the soil, you can use the bottom-up method, which involves sitting the container in a shallow tray of water for about 20 minutes or until the soil surface feels slightly damp.

Using The Soak and Dry Watering Method

  • If you have visual access to the soil, you can use the soak-and-dry method to lift the stems and leaves instead.
  • This method involves pouring the water slowly enough that it gets soaked up by the soil as fast as you’re pouring it.
  • Work your way around the container evenly, ensuring you don’t get the leaves wet.
  • Stop when the soil begins to have trouble keeping up, or you see moisture beginning to seep from the drainage holes.

By watering using these two methods, you’ll avoid creating conditions that attract gnats while keeping your plants happy and healthy.

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