Does chili powder actually deter animals from digging in your garden?

Shutterstock/Candice Bell

If you’ve ever stepped outside to find your newly planted flower bed overturned or your vegetable garden ravaged, you can relate to my frustration. From inquisitive foxes to hungry squirrels, garden mammals wreaking havoc on your carefully nurtured plants can challenge the patience of any gardener.

This is why garden centers are filled with all sorts of deterrents, from motion-activated ultrasound devices to intimidating steel traps and even bags of dried lion dung to safeguard your precious plants. But what if a simpler, more affordable, and gentler solution lies within your spice rack: chili powder? Is this popular gardening hack truly effective?

The concept is straightforward. Like humans, garden mammals respond to capsaicin, the spicy component found in chili peppers. When it binds to receptors in your mouth and skin, it elicits the familiar burning sensation, making you steer clear of the treated area.

You may wonder why chili pepper plants are adorned with bright, attractive fruits filled with aromatic compounds, while this unpalatable molecule is part of the mix. That’s because birds lack these specific receptors. They are immune to capsaicin. Researchers suggest that chili pepper plants have evolved to produce capsaicin as a selective deterrent to keep mammals from damaging chili seeds during digestion, while allowing birds, which help disperse the seeds, to consume them without issue.

Capsaicin is so effective that it is added to birdseed to prevent squirrels from consuming it. It also deters rats and mice from raiding poultry feed, having effects on rodents that consume and destroy wildflower seeds and nests of rare ground-nesting birds.

For larger animals such as deer and badgers, the results appear less definitive. A 2005 UK field trial revealed that European badgers favored food without capsaicin but couldn’t entirely avoid it over time, nor did they learn to steer clear of it like they do with other deterrents. Given that badgers are known to dig up and consume wasp and ant nests, it’s not surprising that a little chili pepper doesn’t phase them too much, considering.

Now, regarding the complexities. These trials can be hard to compare due to the varying forms of capsaicin utilized, including pure chili powder, chemical coatings, or purified extracts. Moreover, capsaicin is not water-soluble, meaning it doesn’t wash away easily with rain. However, it biodegrades readily, so multiple applications may be necessary, especially for those with low tolerance to its effects. Recurrent exposure can increase sensitivity.

The bottom line? Chili powder serves as a safe, natural, and cost-effective method to deter mammals from your garden. By employing the hottest types of chili powder and rotating them, you can avoid habituation and apply them as needed, while keeping the rest for culinary uses.

James Wong is a botanist and science writer with a keen focus on food crops, conservation, and the environment. Educated at the Royal Botanic Gardens in Kew, London, he hosts over 500 houseplants in his compact apartment. You can follow him on X and Instagram @botanygeek.

These articles will be published weekly at:
newscientist.com/maker

Source: www.newscientist.com

Chemists Uncover “Anchapis” That Enhances Chili Pepper Heat

Piri Piri or African Bird’s Eye Chilli Peppers

Steidi/Alamy

Have you ever made your food too spicy? In the future, there might be “anti-spice” seasonings, inspired by compounds in chili peppers that could help mellow the heat.

The spiciness in chili peppers is due to a compound called capsaicinoids, which activate receptors in the mouth’s nerve fibers, sending signals to the brain that create a burning sensation similar to that of actual heat or painful injuries.

Chilean enthusiasts have developed a Scoville scale to measure the heat levels in various pepper strains based on capsaicinoid concentrations. However, some peppers do not always match their Scoville ratings accurately. To explore this, Devin Peterson from Ohio State University and his team employed liquid chromatography mass spectrometry to analyze the capsaicin and dihydrocapsaicin levels in 10 different chili powders, including Chile de árbol, African bird’s eye, and Scottish bonnet peppers.

They then mixed these powders with tomato juice and presented it to a panel of tasters, ensuring each sample had equal amounts of capsaicin and dihydrocapsaicin, expected to yield a mild heat level of about 800 Scoville units.

However, the tasters perceived the heat levels differently among the 10 types of peppers. This led Peterson and his team to conduct further chemical analyses, revealing that three compounds—capsianoside I, balasoside, and ginger glycolipid A—were present in larger quantities. Interestingly, these compounds did not exhibit the expected heat intensity according to Scoville ratings. All three compounds contain glucosides and glucose.

A group of 37 tasters was then asked to evaluate two samples simultaneously. One sample contained these newly discovered compounds, while the other did not. The placement of each on different sides of the tongue was intended to counteract the burning sensation in the second taste test. The feedback indicated that these compounds reduced perceived heat strength by an average of 0.7 to 1.2 points on a 15-point scale.

“These compounds act as effective ‘anti-spicing’ agents,” Peterson notes. Although the exact mechanism remains unclear, it’s hypothesized that they could alter the nerve receptor responses in the mouth, thereby diminishing the burning sensations.

Understanding the nature of these anti-spice chemicals could enable growers to breed and genetically modify plants, nurturing varieties that produce both fiery and mild fruits.

Peterson believes that utilizing these compounds could lead to the development of consumer products that alleviate excessive heat in dishes, offering relief from intense pain by blocking nerve signals.

“When dining with kids, if the food is too spicy, it can be a deal-breaker,” Peterson says. “The idea of having a natural compound to dial down the heat could be quite intriguing.”

The research methodology, which involved half-tasting, was praised by Barry Smith from the University of London’s Advanced Research School, who added that the Scoville scale isn’t always the most accurate tool for measuring chili heat.

Smith speculates that the perceived intensity of cooling agents like menthol might similarly be diminished by such compounds, much like how capsaicinoids trigger a burning sensation.

topic:

Source: www.newscientist.com

Top 8 of the Spiciest Chili Peppers of 2025

Over the past decade, there has been a fierce competition to discover the world’s hottest chili pepper. Despite numerous contenders for the title, one chili pepper has emerged as the victor with a confirmed Scoville Heat Unit (SHU) score exceeding 2 million. To provide some context, a plain jalapeño typically registers a mere 2,500 SHU.

The spiciness of a substance is gauged on the Scoville scale and quantified in Scoville heat units. Established in 1912 by American pharmacist Wilbur Scoville (hence the name), this scale assesses the concentration of capsaicin, a compound responsible for the piquancy or spiciness found in chili peppers.

Previously, capsaicin levels were determined by a panel of audacious taste testers, but contemporary labs now employ high-performance liquid chromatography (HPLC) and mass spectrometry for more precise measurements. This technological advancement has revolutionized the process of analyzing capsaicin levels.

With this knowledge in mind, here is an inventory of the officially recognized hottest chili peppers worldwide. Although there are purportedly even hotter chili peppers out there (such as Pepper X with an alleged SHU of 3,180,000), their ratings have not been officially validated yet.

8. Scotch Bonnet Pepper – 350,000 SHU

Photo credit: Getty

Commencing the list is the Scotch Bonnet chili pepper, a native pepper renowned for its spiciness found in West Africa and the Caribbean. Though its Scoville peak stands at 350,000, its lower boundary is reportedly around 100,000. Unlike other listed peppers, Scotch Bonnet is neither a cultivated variety nor a hybrid but grows naturally in tropical climates. Widely utilized in Caribbean cuisine, Scotch Bonnet offers a relatively more approachable heat level compared to other chili peppers on the list, but caution is still advised when consuming it whole.

7. Red Sabina Pepper – 350,000-577,000 SHU

Red Savina chili pepper held the title of the world’s hottest chili pepper from 1994 to 2006. With a maximum value of 577,000 SHU and a median heat rating of 463,500 Scoville, Red Savina offers a fiery experience that is slightly more manageable than what follows. When handling chili peppers, it is advisable to wear gloves and avoid contact with the eyes.

Source: www.sciencefocus.com