Pass note and surround area of growth (4,5)

I believe the answer is:

cold frame

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'area of growth' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?

'pass note and surround' is the wordplay.
'pass' becomes 'col' (col is a term for a mountain pass).
'note' becomes 'D' (musical note).
'and' means one lot of letters go next to another.
'surround' becomes 'frame' (I can't justify this - if you can you should believe this answer much more).
'col'+'d'+'frame'='COLD FRAME'

Can you help me to learn more?

(Another definition for cold frame that I've seen is " Nursery provision".)

I've seen this clue in The Daily Express.

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