OK if each spring starts late (4,4)
I believe the answer is:
very well
'ok' is the definition.
(synonyms)
'each spring starts late' is the wordplay.
'each' becomes 'every' (synonyms).
'spring' becomes 'well' (both can mean a source of water).
'starts late' means to remove the first letter (the word begins later than normal).
'every'+'well'='everywell'
'everywell' with its first letter taken away is 'VERY WELL'.
'if' is the link.
(Other definitions for very well that I've seen before include "Probably" , "Expression of (reluctant?) agreement" , "In perfect health" , "Exceedingly healthy'" , "Better than just OK" .)