Yes, ORGANIC is a Scrabble word!

Letter values in Scrabble US: O 1, R 1, G 2, A 1, N 1, I 1, C 3.

Is it a valid word?

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

relating or belonging to the class of chemical compounds having a carbon basis
being or relating to or derived from or having properties characteristic of living organisms
involving or affecting physiology or bodily organs
of or relating to foodstuff grown or raised without synthetic fertilizers or pesticides or hormones
simple and healthful and close to nature
constitutional in the structure of something (especially your physical makeup)

Also: organic fertilizer, organic fertiliser.