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If you've ever stepped outside to find your newly planted flower beds dug up or your vegetable garden emptied, you know my pain. From curious foxes to marauding squirrels, the destruction garden mammals wreak on lovingly caring plants can be enough to test the patience of even the most meek gardener.
That's why garden centers are filled with everything from ultrasonic motion sensor devices to creepy steel traps and even bags of dried lion droppings, all in an attempt to protect your precious plants. But what if there was a cheaper, easier, and kinder option already on your spice rack: chili powder. Is this popular garden remedy too good to be true?
The idea is simple: Garden mammals respond to capsaicin, a spicy chemical found in chili peppers, just as humans do. When it binds to receptors in the mouth and skin, it produces a familiar, sharp sensation that prompts them to avoid the treated areas.
You may wonder why chili plants produce bright, attractive fruits filled with aromatic compounds, only to become saturated with this nasty molecule. Well, that's because birds don't have these receptors, so they are immune to the effects of capsaicin. Researchers believe chili plants have evolved the ability to produce capsaicin as a selective deterrent to repellent mammals that destroy chili pepper seeds during digestion, but without having any effect on birds, which disperse the seeds intact.
Capsaicin is so effective in this regard that it is added to bird food. prevent the squirrels didn't eat it. It is also used to prevent rats and mice from eating birdseed and is effective in rodent prevention eat wildflower seeds and destroy nests rare ground-nesting birds.
For larger mammals such as deer and badgers, the results are less clear. A Field trial in UK, 2005 found that although European badgers prefer bait without capsaicin, this does not stop them completely. Nor have they learned to avoid it over time, unlike other deterrents. It's no wonder given to badgers They have been known to dig up and eat wasp and ant nests, so a little chilli isn't too off-putting.
Now about the nuance. What makes it difficult to compare these trials is that they use different forms of capsaicin: pure chili powder, chemical coatings, or purified extracts. Additionally, although capsaicin is insoluble in water, meaning it is not easily washed off by rain, it biodegrades quickly, so repeated applications are necessary, especially if tolerance to its effects may increase through repeated exposure.
The result? Chili powder is a safe, natural and affordable way to repel mammals in your garden. Use the hottest type you can find, alternate its use to avoid addiction, and apply only where necessary. Then leave the rest for your kitchen!
James Wong is a botanist and science writer with a special interest in food crops, conservation and the environment. Trained at the Royal Botanic Gardens, Kew in London, he shares his tiny apartment with more than 500 houseplants. You can follow him on X and Instagram @botanygeek.
These articles are published every week on the website
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