Does talking to plants help them grow?

No. Or maybe yes. The thing is, no one is quite sure. There's never been a really scientific, large-scale investigation into the subject. The problem is, no two plants will ever grow the same. Of any given pair of plants you can expect one to be slightly stronger and healthier than the other; so a huge number of pairs of plants would need to be tested to see if having a good natter with your vegetation makes much difference.

The idea of talking to plants to aid their growth was first raised by Dr. Gustav Theodor Fechner, a German professor in 1848, in his book The Soul-life of Plants. He thought that plants were capable of emotion, and would respond to the emotions around them, hence talking to them encouragingly would help them grow healthily. The good professor was not the only man with this idea, however. Luther Burbank, the botanist and inventor of the Burbank potato also believed that plants while unable to understand words, could somehow telepathically understand the meaning of speech.

Pay attention, here comes the science!

Before I begin, I'll insert a standard disclaimer. I'm not a botanist, nor am I a biologist. The following comes from research from the Internet, and from what I remember from GCSE biology. Any corrections or suggestions from other noders would be greatly appreciated!

Plants need carbon dioxide

Carbon dioxide (CO2) is an important part of the photosynthesis reaction which gives plants their energy with which they grow and live:

6CO2 + 6H2O -> light -> C6H12O6 + 6O2
Which is to say, plants take in carbon dioxide, plus water, and combine it with light, which gives the plant sugar and oxygen. There are a number of excellent writeups over at photosynthesis if you want more details, but suffice it to say, plants need carbon dioxide, which you breath out whilst talking.

The only problem are the quantities involved. In order to make much difference, you would have to talk to your plant for several hours, and at very close range.

Plants take this carbon dioxide from the air around them

Plants take the carbon dioxide they need from their surroundings, and expel oxygen. In perfectly still air, eventually plants will use up all the carbon dioxide in their immediate surroundings.

In still air, the region around a transpiring leaf will become saturated with water vapour so that no more can be absorbed from the leaf; in consequence transpiration is much reduced. In moving air, the water vapour will be swept away from the leaf as fast as it diffuses out, so that transpiration continues rapidly.
- From Conditions Affecting Transpiration Rate in Plants, by tonto.

What better way to move some air around and give out precious carbon dioxide than having a good heart-to-heart with your favourite house plant?

Playing music to plants

If the idea of talking to your plants still sounds bizarre, then even more dubious is the idea that playing music to your plants might help them grow. In fact, a number of people have released whole albums dedicated to providing maximum growth.

Back in the seventies, a nice lady named Dorothy Retallack published a book entitled The Sound of Music and Plants, which chronicled her experiments with playing music to plants. Always using a test group, she experimented with continuous tones, different volumes, different genres and differing play list lengths. Her results, if they can be trusted, are startling.

Retallack discovered that plants subjected to calm, soothing music in short busts not only grew quicker, but actually leaned towards the source of the sound. Plants listening to satan worshipping rock and roll (Jimi Hendrix and Led Zeppelin, for the record) actually leaned away and died. Amazing. Through a series of further experiments with different genres, Retallack concluded that plants like strings best, and loud percussion least.

In the end, who knows?

Perhaps it's the vibration of the air that stimulates plant growth, or the changes in air pressure, or the levels of carbon dioxide, or ambient air temperature. No-one really knows for sure. Music might help your garden grow strong, and so might talking to your plants. And even if it doesn't help your rockery or rose bush, perhaps it might help you; talking to a sympathetic ear can be a great stress buster!

Resources and Bibliography

  • Ask Yahoo! Does talking to plants actually help them grow?
  • Alaska Science Forum: Talking to plants
  • Bad Fads Museum: Talking to plants
  • The DoveSong Foundation