Growing grain is tricky (7)
I believe the answer is:
raising
'growing' is the definition.
('raise' can be a synonym of 'grow')
'grain is tricky' is the wordplay.
'tricky' indicates anagramming the letters.
'grain'+'is'='grainis'
'grainis' with letters rearranged gives 'RAISING'.
(Other definitions for raising that I've seen before include "Promoting (in rank)" , "Growing" , "Bringing up" , "Elevating" , "Lifting" .)