Initially pick each vegetable (3)
I believe the answer is:
pea
'vegetable' is the definition.
(I've seen this before)
'initially pick each' is the wordplay.
'initially' indicates taking the first letters.
'each' becomes 'ea'.
The initial letter of 'pick' is 'p'.
'p'+'ea'='PEA'
(Other definitions for pea that I've seen before include "Ape this plant awkwardly" , "Seed eaten as vegetable" , "Climbing plant; vegetable" , "Spherical vegetable" , "Little green vegetable" .)