I've got some leftover reflective insulation material that is widely used in construction here in europe, I thought that would do for the walls, the floor is gravel and can take soil & water etc. without problem, the ceiling (2.1m high) has some solid studs for hanging the lights/ filter already, plus I can put shelves in there for seedlings if needed... the tents I see always seem to have the vent ports in awkward places for my location, but I'll have a proper look after the responses point towards tents. So now the question is, who makes 5 star tents?!!