How to Get Rid of Outdoor Gnats

  • Written By Dan Edwards on February 2, 2021
    Last Updated: February 2, 2021

There’s nothing better than spending long summer evenings outside. You knock up some awesome food on the grill, crack open a few cold ones and relax with friends and family.

Then, an army of gatecrashing gnats decides to join your party. Knowing how to eliminate them means these insidious invaders don’t spoil your quality time.

Get rid of outdoor gnats with the following techniques:

  • Clean the garden
  • Change your light bulbs
  • Use fans
  • Make a wine trap
  • Take down parasols

The Top Eight Outdoor Gnat Cures

Getting rid of gnats requires a two-stage approach. You first need to ensure your outdoor areas aren’t gnat-friendly and then eliminate the critters, should they still put in an appearance.

1. Reduce Overly Moist Areas

Gnats require moisture. Some species, such as the fungus gnat, feed on fungi that proliferate on damp soils. All gnat larvae also need a wet environment to prevent them from drying out.

Research shows that reducing the moisture content from 90 percent to 30 percent in soil rapidly reduces gnat numbers.

Steps to take include:

  • Unclogging gutters and downspouts
  • Allowing air conditioners to drain into sealed containers
  • Ensuring outdoor taps aren’t dripping
  • Having covers over drains
  • Putting a waterfall in ponds to prevent standing water
  • Not overwatering plants
  • Adding sand to the soil to increase drainage
  • Avoiding leaving full water containers outside — such as watering cans or buckets
  • Fixing leaking pipes

2. Clean up the Yard or Garden

Many gnat family groups lay their eggs in soil and organic matter — their larvae feed on the rotting plants, moisture, bacteria and protozoa that it contains. Reducing the abundance of these gnat hotels will dramatically lower their proliferation in outdoor areas.

Ensure that you:

  • Use a compost bin; don’t make a heap
  • Clean up and dispose of grass cuttings, leaves and garden debris — don’t pile them up
  • Remove fallen fruit
  • Cover plant topsoil, where possible, with stones or slate

3. Remove Overhead Coverings

Carbon dioxide — CO2 — attracts gnats. Unfortunately, as you’re expelling this gas every time you exhale, you’re continuously luring these critters towards you. Stopping breathing is an extreme measure that we wouldn’t recommend!

Overhead coverings, such as awnings, tarpaulins, table parasols and gazebos, can effectively ‘trap’ CO2, — a flashing neon advertisement to gnats. During the day, they may be essential to keep off the powerful rays of the sun. As dusk approaches, and the tiny fliers become active, take them down to release the gas.

You can also use the gnat’s predilection for CO2 against them. Buy off-the-shelf carbon dioxide traps, which lure the mini-monsters inside and capture them.

4. Change Outdoor Light Bulbs

Gnats will flock towards UV light. This is particularly annoying in the evenings if your outdoor illuminations are located near your seating areas.

Replace standard light bulbs with yellow LED bug-lights. These don’t emit any UV rays or warmth, and, therefore, don’t tempt gnats — or other flying insects, such as mosquitoes or moths.

5. Clean Sewers and Drains

Not only does the build-up of grease, grime and kitchen waste promote stagnant water, it also provides a breeding ground for these unwanted critters. This is particularly the case for sewer gnats.

The larvae of these creatures feed on the food-rich biofilm. Remove their nutritional source, and you will eliminate the pests. While this will eradicate many outside gnats, it also has the bonus of reducing their numbers in indoor areas such as sinks, baths and toilets.

Use a wire brush or specialized drain tools to remove caked-on detritus. Flush with boiling water, and then add a mixture of bicarbonate of soda and vinegar to remove any final remnants.

6. Use Outdoor Fans

If the weather permits, use outdoor fans around your sitting areas.

Gnats are particularly weak fliers. Strategically positioned fans can push these miniature menaces away, and may also prevent larger flying insects from attacking your food and drinks.

7. Dish Soap and Wine Trap

If you’re having an outdoor gathering, chances are there’ll be some wine around.

Unattended glasses will attract gnats, but you can use their alcoholic desires against them by making a wine trap.

You need:

  • A small container — like a whiskey tumbler
  • Wine — red seems to be more efficacious than white
  • Dish soap
  • Plastic wrap

Pour some wine into the bottom of the glass to a depth of around 0.75 inches. If any guests have left any dregs, you can use those.

Put 4–6 drops of dish soap into the wine and mix. Cover the top of the glass with the plastic wrap, and make small pencil-sized holes in the top. 

The gnats will be lured into the glass by the aroma of the wine. Stooping down for a drink, they’ll become trapped in the water and drown. The soap breaks the surface tension, so they can’t ‘walk’ on the wine. If they do manage to evade the liquid, the plastic wrap makes it exceedingly difficult for them to break free.

8. Egg Trap

This baiting trick is particularly effective against eye gnats — the incessant creatures that are obsessed by flying around your face.

Gather together:

  • Numerous 1-liter plastic soda bottles for multiple traps
  • A 1-gallon container — you can use a bin or bucket
  • Four eggs
  • Water
  • String

Crack the four eggs into 1 gallon of water and mix thoroughly. Individually fill the 1-liter bottles a quarter full with this liquid and screw on the lids. If you have any of the solution left over, store it in your refrigerator.

Pierce the top section of the 1-liter bottles with around 10 holes in random areas. Tie the string around them and hang in a variety of areas in your garden — between 3 and 5 feet from the ground. Attracted by the smell, the gnats will enter the bottles and become trapped.

As the eggs begin to go off, you should find they become more attractive to gnats. Since this aroma is particularly unpleasant, it’s wise to hang the traps in areas where you don’t relax. Change the mixture every two weeks to improve potency.


Gnats shouldn’t ruin your valuable outdoor time. Using the above tips will drastically reduce populations of these exasperating creatures, without resorting to harsh chemicals. A little bit of time, elbow grease and a few household items, and you’re on your way to a gnat-free garden.