Need to cultivate first garden (4)
I believe the answer is:
eden
'first garden' is the definition.
(I've seen this before)
'need to cultivate' is the wordplay.
'to cultivate' indicates an anagram (I've seen 'cultivated' mean this).
'need' with letters rearranged gives 'EDEN'.
(Other definitions for eden that I've seen before include "heavenly spot" , "Adam and Eve home" , "The original garden?" , "Anthony ---, PM 1955" , "River - garden" .)