According to Medindia, scientists in South Korea have proven that music does in fact help plants grow faster. Specifically, the scientists found that classical music was most effective.
The findings were based on an experiment in which 14 different classical tracks were played in rice fields. It was shown that the rice grew faster when the music was played, which gave scientists the proof they needed to determine that plants have genes that allow them to hear. While it may have been disregarded as a myth previously, it is now arguably a proven fact that plants grow faster when music is involved.