As far as houseplant pests go, fungus gnats aren’t necessarily the worst critters to linger around your plants, but they can be quite the nuisance. They typically feast on soil infected with fungal or bacterial diseases, occasionally feeding on rotting roots. Really, gnats only become problematic when they start to multiply — and once they multiply, they can multiply fast. While it might not live for more than two weeks, an adult fungus gnat can lay up to 300 eggs.
It’s easy to see just how problematic gnats can become, so how can you eliminate them? Ahead, we go over tips on how to prevent these pesky pests from taking over your home and break down tried-and-true solutions for getting rid of them.
While they’re harmless, fungus gnats can be indicative of a more serious problem. The number one culprit behind fungus gnats is, drumroll please, overwatering! True to their name, fungus gnats often feed on fungus in the soil that can grow from overwatering and root rot. When you see them hovering around a specific plant, this may be a sign that you need to cut back on watering that plant.
Before targeting the gnats themselves, it’s a good idea to do a little damage control first. First, isolate the affected plant from the rest of your collection to prevent the gnats from laying eggs elsewhere. Then, repot your plant into fresh soil, removing as much of the infected potting mix as possible. Replace it with a sterile, soilless mix if you can — organic amendments often attract these flying bugs. When you water, use a method such as bottom watering to ensure you never let your plant sit in water.
After doing some damage control for your plants, it’s time to attack the fungus gnats themselves. Luckily, you can easily access solutions for fungus gnats since they’re a pretty common problem — you might even be able to grab remedies from your kitchen or medicine cabinet!
Yellow sticky traps
Yellow sticky traps aren’t the most subtle means of getting rid of fungus gnats, but they are effective. Adult fungus gnats will fly right to them and get stuck. While the traps can become unseemly over time, they will stop the gnats from reproducing. Yellow sticky traps for houseplants are easy to access as well — you can often find them in the pest control area of your local garden center.
Bacillus thuringiensis, or Bt, is used in a popular product called Mosquito Bits, which, in spite of its name, will also help you get rid of fungus gnats. Bt is essentially a bacteria that kills fungus gnats but is considered safe for humans and pets. It comes in pellet form that you can sprinkle directly onto your soil. Before you water your plants, you can also soak the pellets inside your watering can to release the bacteria into the water. Pre-soaking allows the bacteria to travel more quickly to the roots, where the fungus gnats are likely feasting. Mosquito pellets are very effective, as they systematically kill larvae in the soil.
One easy home remedy for fungus gnats is vinegar. All you need is apple cider vinegar, a clear cup, and plastic wrap. Fill a cup approximately one-third of the way through with vinegar, then cover the top with plastic wrap and poke a small hole on top. Adult gnats will fly into the vinegar through the small hole and, as morbid as this may seem, eventually drown.
The next time you water a plant infested with fungus gnats, test out a hydrogen peroxide solution. While hydrogen peroxide might not be as effective as other suggestions on this list, it’s worth a shot since it’s probably already in your medicine cabinet! Use one part 3% hydrogen peroxide and four parts water to soak your plant when you water to kill larvae lurking in the soil.
While you can use a hydrogen peroxide solution as a spray on stems and leaves, it’ll work better in the growing medium since this is where eggs typically hatch. Don’t worry if the soil starts to fizz, as this is what happens when hydrogen peroxide breaks down.
Diluted neem oil is one of the most versatile products for dealing with pests. You can usually find it online or at your local garden center for use on plants. Whether you have scale, thrips, or gnats, it’s definitely convenient to have neem oil lying around to manage pests. Neem oil works by stopping insects from mating and eating, so they eventually die. The drawback with neem oil is that it’s usually a foliage spray, so you probably won’t be able to get it down to the roots where gnats and their larvae attack near rotting roots.
While not necessarily harmful, fungus gnats can quickly grow out of control and may also indicate an overwatering issue with your houseplants. To prevent fungus gnats, key preventative measures include never letting your soil get waterlogged and avoiding organic matter in your soil. If you do find your indoor jungle becoming a home to gnats, there are plenty of solutions out there to get rid of them. With a cup of vinegar or a sprinkle of Mosquito Bits, you’ll be on your way to getting rid of pesky fungus gnats once and for all.
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