Tip: one has to be cut for a salad ingredient (6)
I believe the answer is:
endive
'a salad ingredient' is the definition.
(vegetable used in salads)
'tip one has to be cut' is the wordplay.
'tip' becomes 'end' (tip can mean the end of something).
'one has to be cut' becomes 'I've' (contraction or 'cut' version of 'I have').
'end'+'ive'='ENDIVE'
'for' acts as a link.
(Other definitions for endive that I've seen before include "Plant used in salads" , "Veined (anag) - salad plant" , "Chicory-type salad vegetable" , "Salad plant with crisp curly leaves" , "Edible plant" .)