Hardly a source of barley? (6)
I believe the answer is:
barely
'hardly' is the definition.
(I know that hardly can be written as barely)
'a source of barley?' is the wordplay.
'a source of' is an anagram indicator.
'barley' anagrammed gives 'BARELY'.
(Other definitions for barely that I've seen before include "Not quite" , "By a small margin" , "Hardly" , "how babies are born?" , "just a short while before" .)