Crop needing wind initially, then warmth (5)
I believe the answer is:
wheat
'crop' is the definition.
(I know that wheat is a type of cereal)
'wind initially then warmth' is the wordplay.
'initially' says to take the initial letters.
'then' says to put letters next to each other.
'warmth' becomes 'heat' (synonyms).
The initial letter of 'wind' is 'w'.
'w'+'heat'='WHEAT'
'needing' is the link.
(Other definitions for wheat that I've seen before include "Type of cereal" , "Field crop" , "Grain crop" , "Cereal crop" , "Cereal grain" .)