One case of vegetables (3)
I believe the answer is:
pod
'one case' is the definition.
(pod is a kind of case)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for pod that I've seen before include "Seed holder" , "Seed container" , "Seed case of peas" , "cocoon" , "Seed carrier (eg, pea)" .)