Yes, PLANTS is a Scrabble word!

Letter values in Scrabble US: P 3, L 1, A 1, N 1, T 1, S 1.

Is it a valid word?

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

buildings for carrying on industrial labor
(botany) a living organism lacking the power of locomotion
an actor situated in the audience whose acting is rehearsed but seems spontaneous to the audience
something planted secretly for discovery by another

put or set (seeds, seedlings, or plants) into the ground
fix or set securely or deeply
set up or lay the groundwork for
place into a river
place something or someone in a certain position in order to secretly observe or deceive
put firmly in the mind

Also: industrial plant, plant life.