Historic Arctic vessel trapped in ice - not one spot to grow plants (4,5)
I believe the answer is:
cold frame
'spot to grow plants' is the definition.
(frame for growing plants)
'historic arctic vessel trapped in ice not one' is the wordplay.
'historic' becomes 'old'.
'arctic vessel' becomes 'Fram' (Norwegian ship used in several Arctic explorations).
'trapped in' is an insertion indicator.
'not' suggests deleting specific letters.
'one' becomes 'I' (Roman numeral).
'ice' with 'i' removed is 'ce'.
'old'+'fram'='oldfram'
'oldfram' put within 'ce' is 'COLD FRAME'.
(Another definition for cold frame that I've seen is " Nursery provision".)