Growth at factory (5)
I believe the answer is:
plant
I believe this clue is a double definition.
'growth' is the first definition.
(as in plant growth)
'factory' is the second definition.
(a manufacturing plant)
'at' is the link.
(Other definitions for plant that I've seen before include "Place in the ground to grow" , "Vegetable organism" , "One placed in a group as an informer" , "Factory; organism" , "Factory equipment" .)