Factory that goes to pot (5)
I believe the answer is:
plant
I believe this is a double definition.
'factory' is the first definition.
(a manufacturing plant)
'that goes to pot' is the second definition.
(I've seen this before)
(Other definitions for plant that I've seen before include "Industrial machinery or large vehicles" , "Factory - bit of vegetation" , "Vegetable organism" , "Place in the ground to grow" , "Hide incriminating evidence" .)