Any of you built or used poly tunnels? I kind of like some of the ideas in eliot colemans book on gardening such as: using rebar slid into pvc for frames tying the frames to a purlin with rubber from discarded intertube. Possibly sliding the entire structure over 2-3 differant beds. Using row cover or cold frames inside the tunnel to lower the need for heat heating only to keep plants above freezing staying away from heat demanding plants like tomato in the coldest months. Adtionaly in warmer weather i may want to use screen ends to keep insects out humidity in and temps down as much as possible i live in zone 6 and could come close to no heat in most years maybe a few days of heat and should be able to use winter for salads any brascia carrot pea beet potato. As previously stated i would just foget the tomato eggplant pepper corn squash bean etc. december jan feb are realy the only realy cold season here. warm crops could probably survive the rest under poly tunnel or outside in summer. I am thinking about a 10-12 foot wide 6-7 foot high whatever the 20 foot ribs would give maybe about 12-20 foot long. It is quite windy here and i am thinking maybe increase the rib size by at least 1 diameter maybe 2 over standard and possibly uising closer spacing as well as nylon grid reinforced plastic that is often used around here to tent construction sites for brick work in winter. Since it takes 2 ends no matter what i would likely go the 20 ft long.