Gently dampen part of the garden before we turned up (5)
I believe the answer is:
bedew
'gently dampen' is the definition.
'bedew' can be an answer for 'dampen' (I've seen this in another clue). I am not certain of the 'gently' bit.
'the garden before we turned up' is the wordplay.
'the garden' becomes 'bed' (I've seen this in other clues).
'before' is a charade indicator (letters next to each other).
'turned up' says the letters should be written backwards.
'we' in reverse letter order is 'ew'.
'bed'+'ew'='BEDEW'
'part of' is the link.
Can you help me to learn more?
(Other definitions for bedew that I've seen before include "Sprinkle with water (poetic)" , "Moisten (poetic)" .)