How to keep flies off house plants - 6 ways to protect indoor plants from pests

Protect your gorgeous indoor greenery from annoying pests by knowing how to keep flies off house plants

Desk with hanging houseplants
(Image credit: Dobbies)

Leafy indoor plants are an asset to any home, purifying the air and looking really good while they're at it. However, unfortunately, houseplants come with one downside, pests and flies, so we've asked the experts for the best ways to keep  flies off houseplants and protect your house plant ideas.

'One of the most common types of flies you'll find on house plants is the fungus gnat. These tiny, dark-coloured flies are attracted to damp soil and decaying plant matter, so house plants with moist soil environments tend to be most susceptible,' says Ash Read from IndoorPlants.

'You may also occasionally find whiteflies, which look like tiny white moths, or fruit flies, which are attracted to overripe fruit and other food waste.'

So, what can we do to repel pesky insects from being attracted to and munching on our beloved home horticulture? 

plants in home office

(Image credit: Leaf Envy)

How to keep flies off of house plants

From homemade remedies to shop-bought traps, these are the best ways we've found to keep flies from pestering your houseplants.

1. Use Cayenne Pepper

To create an instant fly repeller, mix one teaspoon of cayenne pepper powder with one cup of water in a spray bottle. 

'Spray it near doorways, windows, plants and whenever you see a pesky fly. The smell of the cayenne pepper will also deter other insects, as it is so strong. Other natural, nicer smelling fly repellents include lemongrass, peppermint, eucalyptus, camphor, and cinnamon,' recommends an expert at

Does Cayenne Pepper hurt plant leaves? 'The answer is NO! There are no known side effects of cayenne pepper. Cayenne pepper is non-toxic and won't burn your plants,'  says Sumit Gupta, author at FallsGarden

small plant on bench

(Image credit: Garden Trading)

2. Invest in yellow sticky traps

These are a non-toxic way to catch flies which you can buy on Amazon. They are coated with a sticky substance that traps flies when they land. 

'They are especially effective against fungus gnats and whiteflies. Simply place them in your plant pots or hang them near your plants,' explains Ash Read.

3. Add diatomaceous earth to soil

This is a natural powder made from tiny fossilised aquatic organisms, available to buy from £12 on Amazon

'It's non-toxic to humans and pets, but lethal to flies and other insects. Sprinkle it on the soil surface of your plants to kill and deter flies,' says Ash Read.

4. Spritz with neem oil

This natural pesticide is pressed from the seeds of the neem tree and is non-toxic. 

As a preventative spray mix '1 tsp (5 ml) of pure, cold-pressed neem oil, 1/3 tsp (1-2 ml) of insecticidal/true soap, 1 quart (1 L) of warm water,' says Kevin Espiritu from Epic Gardening

The bugs will ingest the oil solution and perish. 'You'll get repelling of lava and adults. It sort of can disrupt the entire biological entity that is the pest itself,' Kevin adds.

house plants in kitchen

(Image credit: Dobbies)

5. Try Hydrogen Peroxide

A solution of hydrogen peroxide and water can help kill fungus gnat larvae in the soil. 'Mix one part 3% hydrogen peroxide with four parts water, and water your plants with it,' advises Ash Read.

6. Top up pots with a Gravel mulch

Mulch is commonly used on garden borders and beds to lock in moisture and safeguard outdoor plants. This method of protection can be used for houseplants too. Cover the surface of the plant pot compost with a 1cm-thick mulch of gravel or small stones. Alternatively, for a prettier alternative consider a shell mulch such as Shell on Earth, available at Waitrose Garden.

The cover will prohibit house plant flies from being able to lay their eggs. Be careful not to overwater when using indoor mulch, as it can cause plants to rot. 

Group of house plants

(Image credit: Dobbies)


Why do I have little flies around my house plants?

'Try to avoid overwatering your plants, as soggy soil can attract flies. Regularly remove any dead leaves or other decaying plant matter, and consider using a soil cover like sand or gravel to deter flies from laying eggs in the soil,' says Ash Read.

How do I deter fungus gnats?

Fungus gnats are a nuisance in the home. Leaf Envy recommends making your plant environment less appealing to pests by minimising debris. If dead flowers and leaves are left to decay, fungus gnats are more likely to lay their eggs in the plant debris. 

Fungus gnats love moist environments and will multiply faster in these conditions, so never overwater.

What sprays get flies off houseplants?

Insecticidal soap sprays can be used on both outdoor and indoor plants. The non-toxic solutions won't negatively affect the plant. However, do a sensitivity test first. Spray the solution on just two or three leaves of the plant, and then examine the plant after 24 hours


Rachel Homer has been in the interiors publishing industry for over 15 years. Starting as a Style Assistant on Inspirations Magazine, she has since worked for some of the UK’s leading interiors magazines and websites. After starting a family, she moved from being a content editor at to be a digital freelancer and hasn’t looked back.