This can be done during Chapter 6, either 6A or 6B.
When you are outside of the asylum (if exited through the door just before the wards), turn left and you will see a construction site - dont go towards it.
Instead, you want to go down the stairs which are located behind some fencing on the right, just before the construction site.
Walk past the scafolding and continue along the natural path. A very tiny cutscreen will trigger. Continue along past some old tyres, crates, and a trolley on the left
Walk past the greenhouse a little bit unitl you see some more crates and an open door. You may enter. Another mini cutscene will happen. Walk through the greenhouse and the trophy will be yours.