Machinery put in the ground (5)
I believe the answer is:
plant
This clue is a double definition.
'machinery' is the first definition.
(I've seen this before)
'put in the ground' is the second definition.
(I've seen this before)
(Other definitions for plant that I've seen before include "Member of vegetable kingdom" , "Hide incriminating evidence" , "Machinery; snooker shot" , "Put in soil" , "Factory - bit of vegetation" .)