… iron, not working over fold, to turn red, perhaps? (5)
I believe the answer is:
ripen
'turn red perhaps?' is the definition.
(as in a fruit ripening)
'iron not working over fold' is the wordplay.
'not' suggests deleting specific letters.
'working' becomes 'on'.
'over' shows that the letters should be reversed in order.
'fold' becomes 'pen' (both can mean an animal enclosure).
'iron' with 'on' taken away is 'ir'.
'ir' back-to-front is 'ri'.
'ri'+'pen'='RIPEN'
'to' is the link.
(Other definitions for ripen that I've seen before include "Season" , "Become mature" , "Get ready for 2" , "Grow mature like fruit" , "Come to fruition" .)