Re: why does music affect plant growth?

As you probably know, sound is a wave, and more specifically, a pulse wave. This simply means that it is formed by areas of higher and lower pressure in the atmosphere through which it travels. Terms such as "amplitude," when used in reference to sound, are actually referring to the plot of the air pressure versus time on a graph. Now, it is difficult to beleive that such (extremely small) fluctuations in air pressure could have any effect on a plant's growth. There is very little difference, to a plant, in music and ambient noise.

However, you might want to consider this question from another perspective. It is possible that in an experiment, plants which are exposed to music may grow more than plants that are not. Why? Because even though it is unlikely that the plants themselves respond to the music, their caretakers do! Maybe the plants which are exposed to music receive better care than those which do not. Might be worth looking into!