Does hair grow grey or turn grey?

A single hair grows for one to three years, then you shed it — and grow a new one. As you age, your new hairs are more likely to be white. "Every time the hair regenerates, you have to re-form these pigment-forming cells, and they wear out," says Oro.

it comes from the root and not your existing hair if that is what you mean by it grows grey. only new hair that grows will be grey

Hair loses it's color.  Grey is just some of the old color not gone yet.  White is total loss of color.

Yeah - grows gray . . . . I'm blond and they're hard to see, but am beginning to see some gray/white roots.  DARN !!!!

Grows grey. 👨🏻‍🦳

Your hair doesn't turn gray, it grows that way.