In a very nice episode of Myth Busters (Discovery, part 1, part 2), they've tested whether plants grow harder or not when listening to classical or rock music, talking to them, abusing them. It seemed that Heavy Metal music is best for growing plants, any music is better than none and talking sure helps a lot.
It is also my practise in the darkroom: all kinds of music, depending on the state i'm in, I sometimes abuse my prints verbaly, and sometimes I tread them nice, talk to them in a soft voice. They still don't grow on me, but the effects are that I have a good time and I often laugh about me...