Bad harvest -- it's not hard to be very hungry (6)
I believe the answer is:
starve
'be very hungry' is the definition.
(I've seen this before)
'bad harvest it's not hard' is the wordplay.
'bad' indicates an anagram.
'it's not' is a deletion indicator.
'hard' becomes 'h'.
'harvest' with 'h' removed is 'arvest'.
'arvest' is an anagram of 'STARVE'.
'to' is the link.
(Other definitions for starve that I've seen before include "Suffer extreme hunger" , "Go hungry" , "Eat nothing" , "Averts (anag)" , "Die of hunger" .)