Turn up the music! My plants can't hear it! Okay, there goes a cheap attempt at humor... In all seriousness, I was always told as a child that plants respond to music. I have since heard many variations on the theme but basically the ideas is that plants, when exposed to music, respond with increased growth. To take things one step further, it would seem that plants have something akin to musical tastes, preferring classical to rock music.
Is there any real scientific evidence to this or is it all just a bunch of silly pseudoscience? Also, if it is true, what could possibly be going on within the plant that causes a response to music, something we thought was reserved to lifeforms with the proper sensory equipment?
The truth is, there is not much real science to base these assumptions on. The internet is full of anecdotal tales and "experiments" that hinge themselves on new age belief systems. In fact, the first "experiments" on how music influences plant growth was done by a woman named Dorothy Retallack.
Retallack claimed that plants exposed to classical music grew vigorously whereas plants exposed to rock music languished. Considering how much heavy metal my houseplants are exposed to, I think I have more than enough evidence to say otherwise. Besides her poor experimental design, Retallack was heavily motived by quite a conservative, religious agenda. She had it out for mean old rock n' roll and was damned if she couldn't prove her point. What work has been done since Rettalack's time is tantalizing at best but from this point on, keep in mind that the jury is still out on this topic.
So, why would plants respond to music? They don't have ears or anything in their biology that would function as an auditory device, right? Let's re-frame the question in a more basic sense. What is music? Music is nothing more than organized sounds and sounds are nothing more than pressure waves, that is, disturbances in the atmosphere, a process akin to wind. Plants do, in fact, respond to wind, however, wind is a far more physical force than music. Wind can blow over entire swaths of forest whereas music cannot. What mechanism exists that could possibly explain a plant having any kind of response to music?
Plants respond to heavy wind by growing smaller or by hugging the ground (think alpine vegetation). High winds could generally be seen as a taxing force in the plant world so why would music make plants grow taller and more vigorous? In my opinion, this idea is not a satisfying explanation. As stated above, music doesn't come close to the raw physical power of wind so there could be something else at work.
In a study done by Margaret E. Collins and John E.K. Foreman out of the University of Western Ontario in London, Canada, they demonstrated that plants responded to different kinds of tones. The tones were either pure (without variation) or random. The results did not show any sort of negative responses from the plants, but rather the plants showed different rates of growth. Plants exposed to pure tones grew better than those exposed to random tones.
The mechanism they hypothesized for the increased growth in pure tone plants was that the pure tones were able to move air, however slightly, around the leaf. Plants don't like stagnant air and thus, slight air movement is likely to be more beneficial. The random tones did not produce as vigorous of a response, but the plants still grew. It is possible that the random tones caused less air movement around the plants and, because of this, they did not grow as quickly.
Another explanation that seems plausible was put forth by USCB via their science line. They feel that one possible explanation is that the plants aren't the ones responding to the music, but rather the gardener. If you are listening to music while caring for your plants, then chances are it is music you enjoy. If you are like me, then music really has the power to put you in a good mood. If you are in a good mood then chances are you are more likely to take better care of your plants.
All in all, this is an interesting idea. As I said above, the results are mostly controversial and new agey. There are some tantalizing papers that have been published but their methods have been heavily scrutinized. It seems like this is one of the more popular science fair projects for kids to explore and really, anything that gets kids thinking about science and plants is a cool idea in my book. Until more hard science is done on the subject, we can't say for certain. Either way, I will continue to rock out to my favorite tunes and maybe, just maybe, my plants are benefiting from it too.
Further Reading: [1] [2] [3] [4]