Spent today building tunnel cloches from free 10mm ply and pine(?) slats from free packing crates.
Design is a pair of ply barn style ends(profile from old chase cloche wires),about50mm wide, cut out with jigsaw. Slats run up in approx 32mmmx thickness of board(32mm?)x 1200mm. Five of these nailed between ply ends . 1000g clear polythene tacked on and wrapped around slats 1 &5. A solid ply end for each,a simple (hotbed) cast handle on ridge for transport. Heavy enough to resist recent winds (To 55mph!)
Before covering, all parts brushed with 'food grade' linseed oil(from horsey suppliers, its VAT free too!, and a little paraffin. Seems water repellent, should give extra few years life. Production so far is 14.
Variation planned to cover some with debris netting for ventilated protection and the waste from each sheet used to make some pea guards with 1?2 wire netting (yet to be sourced) Because of the barn shape they can be stacked together for storage and I plan to make a covering , 1 slightly larger version to protect the polythene from out of use sunshine scorch, using black butyl pond liner