Fungus gnats. They’re the bane of any plant lover’s existence. Tiny little pests, fungus gnats are attracted to moisture and love to hang out in waste bins, or worse – around our beloved, freshly-watered houseplants.
While a small number of fungus gnats won’t do much harm to either you or your plants, they’re not pleasant to have in or around your home. In large numbers, however, fungus gnats and larvae can damage roots and stunt plant growth.
So, if you’ve noticed the winged pests swarming around your houseplants, it’s time to take action and keep your most prized plant possessions safe from harm’s way.
Do I Need to Get Rid of Gnats?
First and foremost, let’s make sure it’s fungus gnats that are invading your precious plant haven. Since gnats are often mistaken for fruit flies, identifying the correct pest will help you to treat and solve the problem.
Fruit fly vs. fungus gnat
Fruit flies have a rounded silhouette that’s similar to that of the house fly, albeit marginally smaller. Fungus gnats, on the other hand, have dangling legs and long bodies that resemble the mosquito. Unlike gnats, fruit flies pose no harm to your houseplants and are simpler to eliminate from the home environment.
Symptoms of a fungus gnat infestation
Since fruit flies pose no harm to your plants, fungus gnats can easily be identified by the symptoms they cause. A fungus gnat infestation can cause a host of plant problems including (but by no means limited to!) root rot, stunted growth, and yellowing leaves.
Where do gnats come from?
Getting rid of fungus gnats starts with finding the source. Adult gnats are known to lay their eggs in the moist materials of compost, mulch, and dirt. After hatching, the larvae are attracted to the sweet scents of fresh produce, food spillage, and decomposing matter.
DID YOU KNOW? Despite having an incredibly short lifespan of just one week, one gnat can lay up to two hundred eggs!
Fungus gnats thrive in wet, humid conditions such as greenhouses and potted plants.
How to get rid of gnats
When it comes to killing gnats that have made themselves comfy and cozy in your plants, we have a tricky job on our hands: to eliminate the pests without harming either roots or foliage.
How to get rid of gnats: Homemade gnat trap
There are many options when it comes to homemade gnat traps, some more effective than others. Our favorites include:
Hydrogen peroxide solution
The best and most effective homemade gnat traps are hydrogen peroxide mixtures. Unlike other mixtures that eliminate only the gnats, not the larvae, hydrogen peroxide kills larvae on contact, tackling the root problem.
To create a homemade hydrogen gnat trap, simply mix four parts water with one part hydrogen peroxide and spray generously onto the soil of your houseplants.
Neem oil spray
Neem oil is a natural pesticide that’s pressed out of the seeds of neem trees. Just like hydrogen peroxide, neem oil can be diluted with water. Unlike hydrogen peroxide, neem oil solutions kill both larvae and fungus gnats and thereby speed up the process of eliminating the pests for good.
To create a neem oil spray, simply mix a teaspoon of dish detergent with a gallon of water and two tablespoons of neem oil. Pour between two and four cups of the solution directly onto the soil.
Vinegar is another key ingredient in a homemade gnat trap. With a strong and sweet smell, vinegar is highly attractive to fungus gnats, making it a great option for luring and trapping pests. An additional benefit of a vinegar solution is that it doesn’t need to be applied to your plant and therefore poses no risk to your luscious green leaves.
To create a vinegar gnat trap, simply add two or three drops of dish detergent to a cup of white vinegar and place the solution next to your plant to divert the fungus gnats from your plants and into the trap.
If you’d rather not risk adding a DIY solution to your plants, sticky traps do a good job of catching any fungus gnats (and other pests!) that spend a little too long around your plant. However, since sticky traps are only effective at killing the fully-grown fungus gnats, they are more effective for preventing future infestations than solving existing problems.
How to keep gnats away
Now that your plants are happy and healthy again, it’s important to maintain upkeep to keep the pests at bay.
Keep an eye on your plant conditions, and allow the top one or two inches of soil to dry out before watering. This will avoid the damp conditions that attract fungus gnats to your plants.
For plants that simply can’t seem to drink enough, try adding a layer of sand on top of the soil. This will cover any exposed moisture and keep fungus gnats and their dreaded eggs away from your precious plants.
Pots with good drainage systems help to eliminate eggs from your plants without much fuss. When watering and nourishing your plant, the drainage holes will allow larvae to pass through and wash away from your plant. Likewise, good drainage will help to prevent root rot – a double win in our eyes!
A fungus gnat infestation is a common problem that’s not likely to go away on its own. Whether treating an existing infestation or preventing a future pest problem, our tips will help you to keep your houseplants safe from harm without much effort on your part.