Stoner wasted morning in production (2,6)
I believe the answer is:
on stream
'in production' is the definition.
(I've seen this before)
'stoner wasted morning' is the wordplay.
'wasted' indicates anagramming the letters.
'morning' becomes 'am' (as in 12:00 AM).
'stoner' with letters rearranged gives 'onstre'.
'onstre'+'am'='ON-STREAM'
(Other definitions for on stream that I've seen before include "A monster (anag.)" , "In operation; storeman (anag.)" , "In operation or existence" , "in production" .)