Talking to plants is common, believe it or not. A couple of weeks ago, I came across an article in the Daily Mail on how plants scream when you cut off their stems. This claim of human-like, if morbid, behavior in plants led me to investigate, and soon enough, I was looking into scientific journals on whether talking to plants can affect their growth.
Does talking or singing to your plants make them healthier and grow faster? While there are a few studies that show that plants are affected by talking and other sounds the results are inconclusive. The research that has been done has been tantalizing and sometimes had some surprising results. Most scientists think additional research is needed.
However, the belief that your plants need conversation has been around for quite some time, and expert gardeners swear by its effectiveness. Plus, the studies that did touch on the subject have some pretty interesting findings.
What Science Says
A review of the literature was conducted in 2013 by researchers at Yeungnam University and Chungnam National University in Korea. This review shows the various studies on the effects of sound waves on plants.
These studies show that:
- Sound can encourage seed germination and plant growth.
- Different plants respond to different frequencies and intensity of sound.
- Music can help tomato and barley grow better.
- Music or sound with frequencies of 5 kilohertz and intensity of 92 decibels led to more roots and denser plant dry weight of winter wheat.
- Sound not only made strawberry plants flourish, but it also made them more resistant to insects and diseases.
- Music made okra and zucchini seeds sprout, while the noise did not.
- Sound waves at 1,000 Hertz and 100 decibels helped seeds of Echinacea Angustifolia, a species of sunflower, to germinate faster, as well as have a higher germination rate.
- Aside from the higher and faster germination rate, sound can lead to plants having longer stems and better roots.
- At proper intensity and frequency, sound promotes cellular growth in plants.
- Sound waves increased the production of protective enzymes and allowed it to release more oxygen and other free radicals.
Now that we have an idea of how sound affects plant growth, let’s look at some of the more interesting studies on the subject.
Talking to Plants May Help Them Grow and Bear Fruit
The Royal Horticultural Society decided to look into the claims that talking to plants will help them grow. In an experiment (which you can read about here), they used tomato plants exposed to a variety of voices that were piped into their pots via headphones.
Different plants received recordings of different voices. For instance, one plant had a woman reading snippets of literature, while another plant listened to a male voice. There was also the control group or the tomato plants that did not have the MP3 headphones piping sound into their pots and were allowed to grow in peace and quiet.
The RHS study (found here) claimed that women’s voices made the tomato plants grow taller than those that were exposed to male voices.
More specifically, the tomato plants exposed to female voices grew an inch taller than the plants that were listening to male voices.
Music Can Help Plants Grow
The RHS study was built on the fact that music between a specific frequency range can alter gene expression in plants. Gene expression is the process wherein the DNA code in plants is translated into instructions for growth and other biological processes. This effect helps the plants grow better.
In 2007, Mi-Jeong Jeong, a South Korean scientist at the National Institute of Agricultural Biotechnology, and his team found that playing Moonlight Sonata helped rice plants grow and blossom faster. The researchers played several musical pieces and then monitored the gene expression of these plants.
In this particular study, the researchers found that frequencies between 125 to 250 Hertz made the genes identified as Ald and rbcS more active. Music at these frequencies had the same effects, even at night.
Meanwhile, a different study conducted by researchers at the Sheth LUJ and Sir MV College of Science in India showed that plants exposed to ancient Indian chants grew taller by more than five inches compared to those that were grown in silence.
Sound Helps Plants Protect Themselves, Too
Sound not only helps plants grow, but it also helps them protect themselves from predators. When plants encounter an insect or bacteria for the first time, they “learn” from experience. The next time they face the same predator, they will release defense chemicals that will either drive the invader away or kill it.
Researchers from the University of Missouri used the sound of a chewing caterpillar and found that it was enough to prime the plant for future “attacks.”
The plants that were exposed to the sound released a higher volume of chemicals that acted like an insecticide, while those grown in silence produced a lesser amount.
Probably the most well-known experiment on this topic comes from the TV show MythBusters.
The show set up seven greenhouses where two played nasty speech, another two played complimenting recordings, one played classical ditties, and yet another played heavy metal music. The control greenhouse was left in silence.
The plants that sat in silence grew the least out of all the greenhouses. The winner was the greenhouse that played—ready for this–heavy metal music!
The greenhouses that played music had healthier and taller plants, and they also had larger pea pods.
Talking to Your Plants Help Them Grow: But, Why?
Plants have no ears to hear the sound of your voice when you talk or sing. What could possibly make them grow?
The simple answer is that they might be responding to the vibration created by sound, not by hearing it. This idea is shared by Rich Marini, who heads the horticulture department at Penn State.
Marini, in this article, points out that there is evidence that shows plants can respond to vibration, which can induce or hinder plant growth.
Can Plants Actually Hear?
While most studies conclude that the effects of sound, talking, and music on plants are brought about by the vibrations that these sounds make, there is one study that suggests that plants can hear.
Researchers from the University of Missouri exposed a thale cress plant to a recording of a caterpillar eating its leaves. The plant released a mild toxin for caterpillars when it detected the sound.
The plant did not release the toxins in response to other sounds. The researchers are not sure whether the plant feels or hears the sound and how it is doing it. But the results suggest that plants can determine one sound from another.
The study builds on the findings of Monica Gagliano, a researcher at the University of Western Australia.
In 2012, Gagliano and her fellow researchers published their study that showed roots leaned towards the sound. They suspended a corn plant in water and continuously blasted sound with a frequency of 220 Hertz.
The frequency of the sound is roughly the same frequency that the corn roots also emitted.
And it seems plants are not just silent listeners, but they also communicate. NPR’s science correspondent, Robert Krulwich, explains that plants can warn their neighbors about predators.
Krulwich notes that if you put plants side by side and introduce an insect that will eat its leaves on one plant, the others will be unscathed while the first plant is thoroughly damaged. He explains that if you put aphids, for instance, on a bean plant, it will emit volatile organic compounds that drive away from the aphids. These VOCs can also attract wasps, which feed on aphids.
But the protection isn’t limited to the plant with the aphids eating it. Neighboring bean plants will also emit the same VOCs even when they are not being chewed on by any predator.
While the first plant with the aphids will eventually die or suffer from extensive damage, the others will be protected.
Being Kind to Plants: Will It Help Them Grow?
If you believe that it is the vibration that makes plants grow better when you talk or sing to them, then it should not matter what you say, right? A recent experiment conducted by the furniture maker, IKEA, begs to differ.
IKEA asked children to come up with an insult and a compliment and recorded them. They then exposed one plant to the recorded insults and another plant to the compliments. After a month, the stark differences between the two were very evident.
The plant that was exposed to compliments flourished and was very healthy, while the one exposed to bullying statements wilted.
But Wait, It’s Time for Some Caveats
Why aren’t we hiring singers to sing to our plants? And why aren’t we talking to them about how great our day was or discussing the merits and flaws of the latest Marvel Universe movie?
Because while there may be studies out there that prove plants love music, our voices, and sounds, these studies also acknowledge that plants actually respond to the vibration produced by sound and that they do not exactly hear the sound per se.
There is some scientific evidence that plants love the vibration you create when you sing or talk to them. But it really doesn’t matter if you can sing like Adele or can speak for hours on end, because your plants won’t care.
These studies show that there is indeed a strong relationship between plant growth and sound waves. This means that singing or talking to your plant is beneficial if you want it to grow healthy, but only at certain decibels and frequencies.
Further research is needed to confirm and explore this relationship. What’s more, nobody is quite sure why sound can help your plants flourish. The exact mechanisms have never been pinpointed.
IKEA’s Flawed Experiment
So what about the IKEA experiment then? Some people have taken this experiment as the ultimate proof that plants can indeed hear and that they have human-like emotions. How else can you interpret plants withering and dying at negative words?
Psychology Today published an article written by author and anti-bullying movement critic Izzy Kalman. In his article, Kalman called IKEA a fraud and accused them of rigging the results. He also pointed out that the experiment was not carried out by impartial researchers but by an advertising agency.
Meanwhile, IFLScience noted that the IKEA experiment was based on a study by Dr. Masaru Emoto. However, Dr. Emoto’s studies were pseudoscientific. IFLScience also pointed out that another one of Emoto’s claims was that prayer cleanses polluted water.
In short, the website wrote that the IKEA experiment doesn’t prove anything.
Going back to the MythBusters experiment, the researchers also looked into the effects of nasty vs. nice voice recordings. They concluded that there was no difference between the plants exposed to nasty comments and those that are given compliments.
In that controlled and more scientific setup, both plants grew to the same height and did better than those that were growing in silence.
The MythBusters experiment showed that plants do not care whether you cuss at them or dote on them. They just need the sound waves.
Or, Can It Be Because of Carbon Dioxide?
It is apparent that plants love sound waves because these help them grow. But another thing that plants need is carbon dioxide, which we breathe out when we speak. One prevalent notion is that when you talk or sing to plants, you give them a good dose of CO2.
- The BBC Earth Facebook page asked their followers about how effective singing is in helping their plants grow healthy. Several people responded with their own anecdotes on how their singing also gave them a green thumb.
- Some respondents offered their own explanations, and one of which was that when you sing or talk to plants, you produce carbon dioxide that plants use for photosynthesis.
- There is also evidence that carbon dioxide fertilizes plants. A comparison of satellite observations showed that as carbon dioxide in the atmosphere increases, green foliage also increases.
However, Marini explains that while carbon dioxide does help your plant produce its own food, you might need to talk for hours to get a beneficial effect.
Talking to Plants: A Brief History
Given all the interesting things that we are learning about plants and how they respond to our talking and singing to them, it would be nice to look into how all of these experiments started in the first place. Who was the first person to even think about the possible effects of chatting with plants or singing to them?
It was in the 1840s when a German professor Gustav Fechner published a book titled Nanna (Soul-life of Plants). Fechner proposed that plants can experience the emotions that we humans do.
The idea took root, and over the decades, researchers have been looking into plants sensing the world around them. Talking to plants to make them grow faster and healthier became the subject of several other books. In the 1970s, a dentist named George Millstein recorded an album aptly titled “Music to Grow Your Plants By.”
But the idea of talking to plants had its most famous advocate in no less than England’s Prince Charles. In 1986, the Prince of Wales commented in a television interview that it is very important to talk to plants.
But while Prince Charles was called eccentric and loony for his gardening habits, research indicates that he may have been right all along.
Should You Talk to Your Plants?
Should you ditch that soap on TV and just talk to your plants? There’s literally nothing to lose.
The science might be inconclusive, and there’s no telling if the plants are growing for sure because of your voice. But research has been encouraging, to say the least, and it indicates that plants do derive benefits from the sound of your voice; it makes them healthier, keeps them protected from insects and pests, and makes them grow faster.
Science isn’t just sure why. In the end, however, you are helping them grow healthy, or at least keeping them alive longer.
But even as you wait for something more definite from the scientific community, you should still consider talking to your plants mainly for yourself.
Interacting with plants has been proven to reduce anxiety and stress, both physically and mentally. And as you give them carbon dioxide, they return the favor by giving you oxygen, improving air quality, and regulating moisture inside the room. Plants can also help you become more creative and help improve your problem-solving skills. They can facilitate healing, too.
These benefits are just some of the things that you can get from a plant, plus the obvious ones like having a constant source of food if you’re growing a tomato or kale plant. If your singing or talking helps keep them alive, it’s a small price to pay. Not to mention that talking about things out loud helps clear your mind. Besides, talking to plants is much better than pouring your heart out to your judge-y best friend.