Do conkers keep spiders away?

Greg Baumann, Pest Sherpa

Short answer: No. Authoritative tests have not shown horse-chestnut conkers to be a reliable spider repellent. A small 2018 lab study found chestnut fruit put off some spider species, but that is a long way from proof it keeps spiders out of a house, so it is still not a prevention tool. Treat conkers like other pest myths: interesting story, not control.

What the research says

The honest path in pest management is peer-reviewed or otherwise authoritative work, not seasonal media tips. Research on conkers is limited. Reporting tied to the Journal of Ecology has been used to show that horse-chestnut conkers do not repel spiders. A small 2018 lab study found chestnut fruit put off two of the three spider species tested from settling in a spot, but that is a long way from proof it keeps spiders out of a house, and it is not a prevention method. A Royal Society of Chemistry write-up of a Cornwall primary-school test reached the same practical conclusion: no useful effect from conkers.

Where this sits with other myths

Pest control is full of “myth conceptions,” from pepper lines to homemade trap hacks with little or no value. Conkers fit that list: not proven as spider control.

What to do instead

If spiders indoors bother you, seal gaps around doors and windows, reduce clutter where webs collect, and address moisture that supports prey insects. Species ID and when to call for help are covered in the spiders guide. Bowls of nuts on the windowsill are not a control plan.

Related guides

• Spider Guide
• More Ask the Sherpa Q&A
• Ask the Sherpa: send Greg your question

References

• Royal Society of Chemistry: Pupils scoop prize for unravelling conker theory
• BBC Science Focus: Are spiders scared of conkers?
• Fischer A, Ayasse M, Andrade MCB. 2018. Natural Compounds as Spider Repellents: Fact or Myth? Journal of Economic Entomology 111(1):314-318