learning to play the piano in 20-30 minutes a day by: David from www.piano-play-it.com
Hey Emmy,
20-30 minutes a day is a great practicing time for children at his age!
Your is really learning to play the piano since he's really into it if he can stay concentrated for such time.
More important than the time he's spending is how he spends it.
If he's following his teacher orders and manages his time so that he could play all the homework he got from his teacher through his practicing time he's on the good path to somewhere.
So if I were you I'd pay more attention to see how he's learning his new pieces? is he taking his time to read the notes or to listen carefully to a melody and try to play it by ear with patiance or is he giving up quickly?
One thing is very important. If John chooses to sit next to the piano for 20-30 minutes he's got passion for piano playing. Keep that flame burning!