Gooseberries

Gooseberry or amla has been used as a treatment for hair and scalp problems since decades now and is still considered to be one of the preferable fruits for hair growth. It is also known to enrich hair pigment and is therefore one of the most commonly used ingredients in hair oils formulated for gray hair. When applied regularly this sour fruit can reverse premature hair graying and give you noticeably shiny and lustrous hair.

You can use store bought oil such as the Indulekha Bringha Hair Oil which is infused with the goodness of amla.
Apply the oil generously on your scalp
Let it work overnight or at least a couple of hours before washing off
Depending on your scalp type apply this oil twice a week or thrice a month