Lore, I think it will do really well outside. We put a lot of our vandas out in the summer. Just remember that the more light you give it, the more air movement it's going to need to keep from burning if it's not used to the light intensity. I don't know where you are location-wise, but here, it's very humid in the summer--perfect for them. So no, they don't need to be in a greenhouse year around at all.