Vegetable is planted by school in grassy area (5,5)

I believe the answer is:

swiss chard

'vegetable' is the definition.
(I know that Swiss chard is a type of vegetable)

'is planted by school in grassy area' is the wordplay.
'planted by' says to put letters next to each other.
'school' becomes 'sch' (abbreviation).
'in' is an insertion indicator.
'grassy area' becomes 'sward' (I've seen this before).
'is'+'sch'='issch'
'issch' inserted within 'sward' is 'SWISS CHARD'.

(Another definition for swiss chard that I've seen is " Beet with edible leaves".)

I've seen this clue in The Times.

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