Have to be a big Poly Tunnel, one that you can walk through.My greenhouse serves the purpose admirably and I can control the heat by opening/closing windows and door.
I have a poly tunnel (which i heat during the germination process). I was loused out with tomatoes last year. Would have had more were it not for the fact that my chickens ate them......
Thanks for your answers. Poly tunnel it is then. I've seen one on ebay for about £60-00... much cheaper than a greenhouse & it's got to go on my allotment. So it'll be cheaper to replace when the scrap men nick it!
A polytunnel is just great for tomatoes. You will need a blower to keep down condensation. If you need to open doors, netting will keep the blackbirds away.