My 13 year old son growth plates haven't started to close yet. does this mean he has a lot of growing left?

Indeterminate: Open growth plates is a non-specific term that just means more growth is possible. A "bone age" is an assessment of the growth plates in the wrist/hand that can be paired with the kids age to suggest growth potential. A bone age of 13 at 13 suggests matched growth and 2-3 years of potential. A bone age of 11 would suggest more,14 less. Most males close their growth plates between16-17.