Will Coffee Grounds Really Keep Lizards Away From Your Home? Our Expert Weighs In

Finding a lizard in your home can be shocking, leading you to search for ways to deter the little critters. Though many sources online present it as an effective solution to ward off lizards in your home, you may want to think twice before reaching for any coffee grounds. Biologist and author of the Gulo in Nature blog Charles van Rees, Ph.D., a conservation scientist and naturalist, spoke exclusively to House Digest on the subject. 

He suggested that coffee grounds may not actually be very useful in getting rid of lizards at all. "As with a lot of other claims about smells that keep lizards away, I can find no evidence in the scientific, peer-reviewed literature that suggests that coffee grounds are an effective lizard deterrent." By using them, you may be gambling with the chance that you will still find lizards sneaking into your home or surrounding areas undetected, which is precisely what you don't want. Below, we'll explore in more detail exactly why this method may not work for everybody.

The probability of it working is uncertain

When it comes to deploying coffee grounds to ward off lizards, there is a possibility that it could work, but there are no guarantees. In an exclusive interview with House Digest, Charles van Rees, Ph.D., said, "Despite what people may say, experts have not tested this concept, and you should take this sort of advice with a grain of salt. Pest management professionals and other for-profit companies are usually quick to circulate ideas like these because it gets them money and attention." 

Many people think using strong smells like coffee grounds as a deterrent works, and van Rees explained why that might be the case. "One mark in favor of this claim is that many lizards do have a reasonably good sense of smell. Many lizards have a well-developed vomeronasal or Jacobson's organ, which gives them a sort of integrated taste-smell sense ... This means that if you put out coffee grounds, lizards around your home will probably be able to smell them. Will that smell keep them away? That's anybody's guess." Essentially, by choosing to use this method, you are taking a gamble. 

Other methods to deter lizards

To determine if it works for you, Charles van Rees, Ph.D., suggested an experiment. "Try comparing two parts of your garden or home, with one 'protected' by coffee grounds and the other not. Do you see a difference in the number of lizards you spot over a week or month?" If there is no change, what might work to keep lizards out of your home?

Thankfully, there are plenty of other solutions that are simple to execute. In the interview, van Rees said, "If you have no luck with coffee grounds, more reliable ways to reduce lizard numbers are strategies like reducing the availability of food that attracts them, and removing potential hiding spots. Fixing up siding, sealing doors and windows to avoid having cracks, or avoiding moving potted plants from outdoors to indoors can minimize opportunities for lizards to hang out near your house or get a free ride indoors." 

He continued to share how you might deter insects that lizards like to snack on. "Some essential oils and strong scents like citronella may deter some insects, which in turn would keep away lizards, who are presumably looking for them. Turning off outdoor lights at night is a great way to reduce the number of moths and other light-attracted insects near your home, which tend to attract loads of lizards looking for an easy meal." It's certainly worth a try. According to van Rees, "These simpler solutions are much more likely to be successful than hoping that lizards are afraid of coffee!"