How do I clean a greenhouse?

So I pressure washed, cleaned and polished, moved a 7 year old greenhouse last summer. It was overgrown with brambles and was pain in the butt to clean. Point is, the humidity seemed to have built up over winter and the entire place is GREEN. The wood fece/panels that are the table/shelves are now completely bright green. The weird thing is, when I was cleaning the greenhouse in the summer, the panels were still brown and not moldy. How do I clean the algae(?)/fungus/mold off without leaving any in? I'm afraid it might cause damping off or infect the seedlings I'm going to leave in there for a week to harden off. Also, the floor is now a weed den, is there a way to kill them organically, cause they're pretty deeprooted cause I dug up that place pretty deep.