Presenting no problems when planted in middle of vineyard (4)
I believe the answer is:
easy
'presenting no problems' is the definition.
(I've seen this before)
'when planted in middle of vineyard' is the wordplay.
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'planted in' indicates putting letters inside.
'middle of' indicates the central letters.
The middle letters of 'vineyard' are 'ey'.
'as' put into 'ey' is 'EASY'.
(Other definitions for easy that I've seen before include "Promiscuous" , "Soft" , "Obliging; go carefully" , "Frederick Marryat's midshipman" , "Relaxed" .)