Plant seeing first of many poorly (4)
I believe the answer is:
mill
'plant' is the definition.
(mill is a kind of plant)
'first of many poorly' is the wordplay.
'first of' indicates taking the first letters.
'poorly' becomes 'ill' ('ill' can be a synonym of 'poorly').
The first letter of 'many' is 'm'.
'm'+'ill'='MILL'
'seeing' is the link.
(Other definitions for mill that I've seen before include "No fun going through this" , "works on > race" , "Fist fight" , "Vacuous" , "Flour is produced here" .)