If you are considering natural ventilation for your cold frame, high tunnel, ground to ground or gutter connected greenhouse Hummert International can design a roll up wall system to meet your needs. The advantages of natural ventilation for your greenhouse-growing environment are numerous and can be achieved with the Roll-Up/Lock Down Curtain Systems by Advancing Alternatives Inc. The Roll-Up/Lock Down Curtain Systems can fit any “straight” or “curved” wall — free standing or gutter connected greenhouse. Available in 4’ increments, systems can be manually operated or motorized with low voltage or line voltage motor drives. The patented Roll-Bar and Roll-Lock, locks down when closed and fully seals across the entire bottom. Optional auto inflation is designed to inflate two layers of poly and seals the ends of the curtain for added insulation, saving you energy and money!