❚ All products were chosen independently by our editorial team. This review contains affiliate links and we may receive a commission for purchases made. Please read our affiliates FAQ page to find out more.

How to get rid of house plant flies (fungus gnats)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
To do

Passionate about your indoor jungle? Find a gorgeous new plant container with our carefully curated collection of the 10 best indoor plant pots, or create an eye-catching display with one these stylish indoor plant stands. Alternatively, you might find our selection of the best indoor greenhouses just what you need to nurture tender specimens?

You Will Need

House plants
Yellow sticky traps
Grit mulch
Biological control for fungus gnats

Step 1: Water less often

Watering the compost

Fungus gnat larvae need damp compost to live, as this is where algae and fungi thrive, on which the larvae feed. Simply by allowing the compost dry out between waterings, you’ll greatly reduce the fungus gnat population.

Step 2: Use a gravel mulch

Covering the compost with gravel

Most commercially available composts have been sterilised, so they don’t contain fungus gnat larvae. If you cover the surface of the compost with a 1cm-thick mulch of gravel, grit or ornamental glass pebbles, this will stop house plant flies from being able to lay their eggs. Avoid using home-made garden compost indoors, as this can be a source of fungus gnats.

Step 3: Use sticky traps

Yellow sticky trap

Yellow sticky traps work by trapping the adult fungus gnats and breaking their lifecycle. Simply hang up a trap near affected plants, or attach it to a bamboo cane inserted into the compost. Keep the trap near soil level, as gnats rarely fly far from the compost. Avoid hanging the traps outside as you'll also trap butterflies and hoverflies.

Step 4: Use biological control

Carnivorous sundew plant

If you have lots of house plants, it may be worth applying a biological control. To tackle fungus gnats use the nematode Steinernema feltiae, predatory mites or rove beetle larvae, and apply according to the pack instructions. These are available from online suppliers. While nematodes can be used in the home, the mites and beetle larvae are best used only in the contained environment of a greenhouse or sealed conservatory. If you’ve only got a few house plants, try growing a sundew (Drosera) nearby, as these sticky carnivorous plants are very good at trapping fungus gnats.