Well it might sound stupid or you might not enjoy classical music, but you can read this and come to your own conclusions...
"The classical music will help the plant growth and that the rock music will hinder its growth since studies have showed that classical music even concentrates the human brain and is good for you."
"Dr. Singh, head of Botany at Annamalai University in India studied plants reactions to Classical and Rock music. While listening to Classical and Baroque music, the plants grew 72% more leaves and they grew 20% faster. The plants which were exposed to Rock music grew abnormally tall and died in 2 weeks. The plants which were exposed to Classical and Baroque music ended up leaning towards the speakers instead of the light and the closest plants began to wrap themselves around the speakers."
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A California State Science Fair project deduced from tests that "Silence grew the best and healthiest followed by spoken word (Harry Potter). Classical Music (Vivaldi Concertos) ended up just under spoken word. Bringing up the rear was a very small and unhealthy plant that was 'listening' to heavy metal and (harsh) world music (Mudvayne and Rammstein)."...
A Wingate University botanist states, "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!"
According to the Plant Physiology Information Website, "...Plants have no ears to hear and no brain to process or develop musical taste or music appreciation...so any attempts to show relationships between music forms and growth or other responses have met with total failure in the hands of true scientists."