I have a 16 yr old granddaughter who wants to improve her height, what can she do? she's 5'2"

Depends on variables: Skeletal maturity determines the duration of linear growth. If the bone maturity is ahead of a persons age, they finish growing sooner. An x-ray of your wrist and hand can be analysed for open growth centers. If closed you are finished growing taller.Most females are done at 16-17, a few with delayed bone maturity continue to grow slightly.Healthy diet, rest and exercise support normal growth.