Despite the layers of grime covering the glass, it's considerably warm in the greenhouse. Other than that, it looks like the place will need some fixing up to be functional again. The only living plant in it is a large, menacing looking blossom that had the good fortune to be growing under a missing pane of glass.
In a corner near the door you can see what appears to be the nest of some animal. The nest is underneath a rusted spigot.