Limit on music about vegetable (8)
I believe the answer is:
capsicum
'vegetable' is the definition.
(I know that Capsicum is a type of vegetable)
'limit on music about' is the wordplay.
'limit' becomes 'cap' (capping is a kind of limiting).
'on' indicates putting letters inside.
'about' indicates an anagram.
'music' with letters rearranged gives 'sicum'.
'cap' going inside 'sicum' is 'CAPSICUM'.
(Other definitions for capsicum that I've seen before include "Eg, chilli pepper" , "vegetable?" , "seeds" , "Tropical plant producing peppers -- music cap (anag)" , "hot stuff perhaps" .)