Yes, GREENS is a Scrabble word!

Letter values in Scrabble US: G 2, R 1, E 1, E 1, N 1, S 1.

Is it a valid word?

GREENS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

any of various leafy plants or their leaves and stems eaten as vegetables
green color or pigment; resembling the color of growing grass
a piece of open land for recreational use in an urban area
United States labor leader who was president of the American Federation of Labor from 1924 to 1952 and who led the struggle with the Congress of Industrial Organizations (1873-1952)
an environmentalist who belongs to the Green Party
a river that rises in western Wyoming and flows southward through Utah to become a tributary of the Colorado River
an area of closely cropped grass surrounding the hole on a golf course
any of various leafy plants or their leaves and stems eaten as vegetables
street names for ketamine

Also: leafy vegetable, william green, green river, putting green, putting surface, k, super acid, special k, honey oil, cat valium, super c.