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Dr Green

Why are there flies surrounding my plant?

Dr Green

Words by Dr Green

Photos by Jaap Scheeren

Hey Doc,

I’ve noticed my plants have been attracting the attention of dozens of tiny little black flies. They are so annoying. Why are they here and how can I get rid of them?




Hi Lucy,

I’m glad you’ve asked this question as your problem is a common one. The tiny little flies you are referring to are called fungus gnats – also known as sciarid flies – and they tend to gather around plants for the duration of their (thankfully) very short 4-6 day lifespan. But the flies are actually the least of your worries. It’s the larvae they lay in the soil which feed off your plant’s roots that will cause you problems. They can even be deadly for younger, more vulnerable plants. There are various ways you can tackle and prevent this issue.

Start by replacing the soil with fresh peat-free compost and add 2cm of pebbles/grit/gravel to the top of the soil. This will make it less hospitable for larvae to grow (and it can even look quite nice!). Actively remove any decaying foliage from your plants and allow the soil to dry up between watering as the flies are particularly attracted to bacteria and moist environments. Place sticky traps around the house to catch adult flies, this will also catch fruit flies and other pesky winged creatures in your home.

And voila! You’re on your way to a gnat-free household. You’ll probably need to deal with a few generations of gnats from the previously laid larvae so don’t be disheartened if they seem to persist for a few weeks.


The Doc x

P.S. Please avoid pesticide! This can be incredibly harmful stuff, so unless you own an organic pesticide or a special type that has been recommended by a trusty source, try to stay away.



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