The screen which is wound up from bottom to top controls air refreshment. The flexible screen (1) and its winding tube are held against the greenhouse wall by flexible straps (6) fixed to the top and bottom parts of the wall exterior. They pass above the winding tube so as to apply a constant force regardless of position. A continuous locking system is formed by one or more profiled elements mounted end to end and fixed on the greenhouse frame. This locking system is arranged to allow the winding tube to bypass the opening and closing of the screen. It is locked underneath when unwinding is completed and rotation is maintained in the same direction causing rewinding.
