here's what i found on black seed oil...
For Loss of Hair & premature Graying.
Scrub the scalp thoroughly with lemon, leave it for 15 minutes, wash away with water and shampoo and dry well, thereafter apply Black seed oil to the whole scalp, continue for a few weeks.
Beard growth (i'd think this would work with hair, too)
Massage the beard area with black seed oil ensuring that the oil penetrates to the roots, this stimulates the growth of the beard and prevents premature hair graying.