Keep spiders out for longer by adding one item to repellent

People wanting to banish spiders from their homes could see results with a simple solution that relies on one important ingredient. Adding a dab of washing-up liquid to a homemade spider repellent of peppermint oil and water is said to make it more effective.

Spider season, typically running from late August through October in the UK, makes it more likely for Brits to notice spiders scuttling about their home. Around this time, adult male spiders have grown to full size and leave their hidden webs or quiet outdoor corners to actively search for females.

Arachnophobes should soon be able to rest easy as the peak usually winds down by mid-to-late October. Although mild weather can occasionally stretch the last few bursts of activity into November.

Instagram user Ally (@A_house_by_the_fairway) claims that ‘the peppermint hack’ is her latest line of defence against invading house spiders that she says seem to be “getting bigger” each year. This method involves mixing 20 drops of peppermint essential oil in a spray bottle with 500ml of water.

She adds that, for enhanced power, a teaspoon of washing-up liquid helps. She said: “Oil and water don’t naturally mix, so the washing-up liquid helps disperse the peppermint oil throughout the water instead of it just sitting on top.

“I’ve been spraying it around window openings, doors, drains and anywhere else I think they might be getting in. I’m basically keeping the bottle close by and dousing things as I think of them.”

The Instagram user claims that this method “can be harmful to pets”. She added: “Be careful where you spray it, and keep it away from anywhere dogs or other pets could lick or come into direct contact with it.”

As a pet-friendly alternative, homeowners might want to rub leftover peels of lemons, limes, or oranges along windowsills, skirting boards, and doors. Spiders strongly dislike citrus fruit aromas – but this natural version is entirely pet-friendly.

Why does this method work on spiders?

Spiders smell and taste through sensory organs (sensilla) located on their legs. Strong, pungent scents like peppermint oil are highly overwhelming and unpleasant to them.

When they come into contact with a surface sprayed with peppermint, the intense aroma acts as a natural chemical barrier, causing them to turn away and avoid entering. Adding the soap acts as an emulsifier, breaking down the essential oil so it disperses evenly throughout the water.

This ensures that every spray delivers a consistent concentration of the peppermint deterrent, rather than just spraying plain water with oil floating at the top. Many common dish soaps (especially lemon-scented varieties) contain the citrus compound limonene.

Spiders dislike citrus just as much as peppermint, so combining the two creates a double-strength barrier. If the soapy spray makes direct contact with stray cobwebs or egg sacs, the surfactants in the soap actively break them down.