A scheme for vegetable production (4)

I believe the answer is:

plot

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'a scheme' is the definition.
(I know that plot is a type of scheme)

I don't understand the remainder of the clue.

(Other definitions for plot that I've seen before include "... of story, family ..." , "Secret plan; graph" , "Conspiracy, secret plan" , "Scheme; graph" , "Scheme or small piece of land" .)

I've seen this clue in the Evening Standard.

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