Salad ingredient is hard to distribute (6)
I believe the answer is:
radish
'salad ingredient' is the definition.
(radishes are often used in salads)
'is hard to distribute' is the wordplay.
'to distribute' indicates an anagram (letters distributed elsewhere).
'is'+'hard'='ishard'
'ishard' anagrammed gives 'RADISH'.
(Other definitions for radish that I've seen before include "Pungent fleshy edible root eaten in salads" , "Hard vegetable" , "Hottish salad plant" , "Daikon or mooli" , "Edible small root" .)