Fungus gnats are those small, annoying black flies that terrorise your plants. Where do they come from? And, more importantly, how you get rid of them? The tips below will help you stamp them out and prevent them from returning — hooray!
Before we start with the steps for prevention and removal, it'd be good to know more about this flying pest. Fungus gnats are most active at the beginning and end of the summer, and they love damp soil. An adult fungus gnat only lives for 1 to 2 days, but females lay over 200 eggs in one go. Once a larva reaches adulthood, she immediately lays new eggs in the damp soil of your beloved plant. It’s no surprise that they’re tricky to get rid of, but we're here to give you some tips on how to deal with their presence and stop them coming back.
How to prevent them
#1 Don't overwater
Fungus gnats love damp soil, so not overwatering your plants helps avoid infestation. It’s no fun laying eggs in dry soil, so the fungus gnats will give your plants a miss!
#2 The right pots
Buy pots with a hole in the bottom, and place them on saucers. That way you'll prevent the damp soil from damaging the roots, as it can cause them to rot.
#3 Keep things clean
Fungus gnats do well in compost-rich soil. Regularly remove dead leaves and twigs from the pots to keep the soil clean, dry and well-ventilated.
How to fight them
#1 Isolate your plants
If you find that fungus gnats have invaded one of your plants, place it somewhere separate for 1 to 2 weeks so that other plants are not infected. To be on the safe side, you should also do this with new plants before you introduce them to the rest of your plants.
#2 Repotting helps
Repotting is an effective way of getting rid of the gnat larvae. Clean the pot thoroughly and place the plant in new, clean potting soil. The rotting roots, plant remains and damp soil that fungus gnats love so much will be completely gone.
#3 Fancy some wine?
Place a saucer of wine near a plant to attract its fungus gnats. Funnily enough, fungus gnats find wine much more appealing than soil. They dive right in and... well, you can imagine what happens next.
#4 Sand it down
Scatter a layer of sand on top of the soil in the pot. Tough sand makes it much harder for the gnats to lay eggs.
#5 Home brew
Boil a litre of water and stir in two tablespoons of cinnamon. Leave to cool and then use it to water your plants— the gnats hate it!
#6 Yellow to make them see red
Fix yellow-coloured sticky paper or yellow traps near your plants. The gnats will fly straight towards it, and get stuck! Problem solved.
#7 Sulphur sufferer
You can rid yourself of gnats with matches — but you don't have to set fire to your plant. Instead, stick the matches head downwards in the soil. The sulphur will put them right off.
#8 Plants to the rescue
Did you know that carnivorous plants love to eat little black fungus gnats? Place a Sundew next to the infected plants, and watch it clean up the flies.
Do you have any more tried and tested tips for getting rid of fungus gnats, or any plants that have survived these problematic creatures? Share your story with us on Facebook or Instagram using #thejoyofplants