Not so green (5)
I believe the answer is:
riper
'not so green' is the definition.
('ripe' can be the opposite of 'green' so perhaps 'riper' is reasonable for 'not so green')
This is all the clue.
(Other definitions for riper that I've seen before include "More mature and ready to be eaten" , "On the way to getting mellow" , "More ready for harvest" , "More ready to pick" , "More ready for picking" .)