Vegetable patch sometimes lost by the inattentive? (4)
I believe the answer is:
plot
This clue is a double definition.
'vegetable patch' is the first definition.
(plot of land)
'sometimes lost by the inattentive?' is the second definition.
(someone not concentrating might lose the plot)
(Other definitions for plot that I've seen before include "are intriguing" , "Secret plan; graph" , "Connive" , "Contrive" , "Conspiracy, secret plan" .)