Rattling around in the new house I found the previous occupants had left a few conkers (horse chestnuts) about the place, probably as a deterrent against spiders.
A few years ago I first heard the suggestion that to stop spiders entering the house you should collect conkers when they fall and place them around the house, by windows and such. The theory being that the spiders don’t like the smell and will scuttle off elsewhere.
Being me, I’ve decided to look in to this claim. Anecdotally, there seems to be some evidence for efficacy, but has anyone actually done any controlled testing? Possibly. A few years ago the RSC had a competition to find out the truth of the matter. A group of school kids performed an experiment that showed that spiders weren’t affected at all, but there are questions about the validity of it.
See this post on Canadian website, Science World for more details.
Some people suggest drilling a hole in the conkers, or putting them in the corners of the rooms in your house. If it helps you deal with your arachiphobia then I see no reason not to continue.