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Do Horse Chestnuts Keep Spiders Away?

Last Updated (Sunday, 02 October 2011 14:41) Written by Raymond Nakamura

While walking our kids to school one morning, I yakked with another Dad about the recent abundance of spiders (he was pulling a web from his hair). He said, "We put chestnuts around our house to keep spiders away." I'd never heard of this before. He acknowledged the weirdness of the idea but insisted on its efficacy.

 

I crawled around the Web and found various versions of this kind of spider repellent, not only chestnut but also horse chestnut, walnut, or the large round fruit of the Osage orange tree. Still others suggested it was the wood, not the nut or fruit. I did not come across anyone mentioning the spikey casing still on. Maybe people with arachnophobia would just like to believe it would be that easy to keep spiders away.

 

In Britain, the notion may be more widespread. Their Royal Society of Chemistry held a contest to find the best evidence for or against the idea that spiders dislike conkers, which is what they call horse chestnuts.

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The winning entry came from a grade five class from Cornwall. They showed that their spiders did not seem concerned about walking over conkers compared to other materials.

 

They were lauded for their efforts and sure it's great that they aren't afraid of spiders, but kids these days seem to get patted on the head for every little thing. I did not expect horse chestnuts to have any effect on spider behaviour, but I'm not sure the idea was tested sufficiently, as the Ranger's Blog has pointed out.

 

1. Not all or even many of the spiders tested would occur in a house. So if the question is whether horse chestnuts keep spiders out of your house, it might be useful to find spiders that would be in your house. Here are some notes about some misconceptions people might have about spiders in BC.

 

2. Harassing the spiders may not be a suitable test of their substrate preferences. It would take longer, but it seems like you'd have to wait to see what spiders do over time. Something else I hadn't realized before was that household spiders aren't coming in from the cold and you aren't doing them any favours by putting them outside.

 

3. Horse chestnuts are inedible, which may support the idea that they contain some chemicals noxious to spiders. Some have suggested you need to open the chestnut up or poke holes in it to take effect.

 

Even if it turns out that horse chestnuts or these other items do not have any effect, I am intrigued as to why people would believe this in the first place. I can imagine a situation where you might happen to have conkers around at the this time of year and the spiders disappear for other, perhaps seasonal reasons.

 

I have horse chestnut trees all down my street, and I don't have many spiders in my house. If you have a lot of spiders in your house and would like to test chestnuts on them, then let me know in the comments and maybe we could collaborate.

 

 

 

Comments  

 
0 #11 Black widows! — Raymond N 2012-05-09 06:35
If had to worry about black widows I probably would not like spiders either. Thanks for your contribution.
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0 #10 RE: Do Horse Chestnuts Keep Spiders Away? — Colin 2012-05-09 04:57
I do not like spiders. I have used horse chestnuts for about 15 years, and simply put them on the floor near the places where spiders are most often seen. I live in a desert area where spiders of many types thrive. Black widows, the most. It made a definite difference the first couple of years and then when an old visitor to my house told me that his parents used to drill a 1/16 th inch hole through the hard shell to help the "whatever" escape,I did this and our house is now pretty much spider free. I leave a couple of sticky traps around once or twice a year for a week to see if spiders are stil around, and coincidence or not, we are pretty much spider free. The black widows and the wolf spiders are non existent inside, but still abundant outside, so I am a believer.
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0 #9 3 for good luck — Mandy 2012-03-22 19:03
Just heard about the spider thing a few days ago. Up until now, my daughter has had three on her window sill for good luck. This is the only room in our Qualicum Beach, BC house, and also the only room that does not have spiders! Not sure what the correlation is, but it's intriguing enough for me to litter the rest of my house with nuts!!!
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0 #8 RE: Do Horse Chestnuts Keep Spiders Away? — Raymond Nakamura 2012-02-22 15:43
I don't supposed you'd want to remove them now and see if the spiders come back?
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0 #7 RE: Do Horse Chestnuts Keep Spiders Away? — Isy Keily-Atkin 2012-02-22 14:39
I heard this rumour about spiders and conkers so when I saw some I collected a few and put them on my window sill and either of the door. I must say I'm convinced it works, the room has not seen a spider in over a year and I used to see one at least once a week. Very grateful for this tip.
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0 #6 Kamloops — Raymond Nakamura 2012-02-15 09:36
The hole drilling idea is interesting. If there is something chemical about the chestnuts. Do you have any old guys on street corners selling roasted chestnuts? Maybe you could find a source that will sell you some and if it doesn't work you could eat the leftovers. I've sent most of my horse chestnuts to the yard composting bins long ago. The seasonality of the problem is interesting. If the spiders come out in the summer and then they wane anyway, but the chestnuts are not available until the fall, then it might seem like the chestnuts are doing something when it was other factors that were resulting in the spiders disappearing. Good luck with your quest.
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0 #5 Chestnuts and Spiders — Cynthia 2012-02-15 09:28
I am absolutely terrified of spiders and have also heard that chestnuts, not necessarily horse chestnuts but chestnuts alone, do keep spiders away and I have heard this from multiple sources. I have also heard that you have to drill a hole in each chestnut although I am not sure why. I have been searching on the internet for locations of Chestnut trees in my city where I live (Kamloops, B.C.) but cannot seem to find any reference sites. Anyone who could help me out or is willing to send me a box would be greatly appreciated! I have noticed the spider population really starts to explode in the summer months so am now trying to prepare with a search for Chestnut trees so I can start picking!
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0 #4 RE: Do Horse Chestnuts Keep Spiders Away? — Raymond Nakamura 2012-01-31 13:59
Thanks for adding your data point. If we can establish a fairly strong correlation between horse chestnut presence and spider absence, then maybe someone can do more actual experiments to zero in what is going on there.
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0 #3 Lord Revelstoke — Bob Eley 2012-01-31 13:17
I had never heard of the chestnut/spider connection until recently. After my aunt's death, we were clearing out the attic in her old house and we all remarked that we never saw any spider webs or any spiders up there. What we did see, however, was an abundance of horse chestnuts spread around on the floors. At home here in Kamloops, we've always had the occasional spider make their appearance, so my wife got some chestnuts and placed them in various places around the condo. I can honestly say, that since the chestnuts were placed, almost a year ago, we have not seen any spiders at all. I don't understand it, but it seems amazing to me.
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0 #2 Thanks — Raymond N 2011-10-09 13:07
Thanks for the feedback. I'm sorry if my skepticism seemed unduly harsh. Also, I inquired at my daughter's school last year and was told conkers were not allowed.
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