Need to transform the garden (4)
I believe the answer is:
eden
'garden' is the definition.
(Garden of Eden in the Bible)
'need to transform' is the wordplay.
'to transform' indicates an anagram.
'need' is an anagram of 'EDEN'.
'the' acts as a link.
(Other definitions for eden that I've seen before include "PM, 1955-57" , "Delightful place" , "Adam and Eve's garden" , "Someone once seen in Number Ten's" , "River - garden" .)