Answer:
This problem involves lots of things in science, but the most important one is how you follow the scientific method. On this belief, people don't follow the scientific method wisely, and instead of trying to do it the right way, they just say it works, when in science, we still don't know.
Singing songs to plants to help them grow is an idea that needs development, we don't know if it really helps or not, and when we don't know it, this is called hypothesis. The hypothesis is an idea that something works in a certain way, and after stablishing that, we need to test it, and in this case, there aren't any controlled tests that could confirm the efficiency of it.