It got warm in the polytunnel this year (50+ quite often) even with the doors open. The quality of the tomatoes was pretty poor, though I got a reasonable weight. The easiest thing to add I think would be one of these round roof vents:(northernpolytunnels site: not allowed to create a proper link as first post) ../hobby-range/polytunnel-ventilation/polytunnel-roof-vent.html This entails cutting a hole in the roof and pushing it in. Has anyone got one and if so how effective is it? or does anyone have any other ideas that might be easy to fit? My polytunnel is 14' x 25' with a good size double-door at one end and a single size ventilation pannel at the other end.