Starchy tubers up north — the ropiest, almost (7)

I believe the answer is:

tatties

'starchy tubers up north' is the definition.
(Scottish term for potatoes)

'the ropiest almost' is the wordplay.
'the ropiest' becomes 'tattiest' (ropy can mean tatty or poor-quality).
'almost' means to remove the last letter (almost the whole word is kept).
'tattiest' with its last letter taken off is 'TATTIES'.

(Another definition for tatties that I've seen is " things growing in the ground".)

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app