You could prop them up on wedges of wood or brick offcuts so some air gets in. If it’s to protect something tender like dahlia tubers that don’t need light over winter, upside down old colanders, hanging baskets, those plastic mesh baskets garden centres used to support potted plants, old pots or shaped chicken wire can be stuffed with straw for cheap winter protection. If they need light forego the straw and just wrap clingfilm over the top of some sort of mesh structure.
Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
This is a good company, although I've never bought cloches from them. It'll give you an idea of the various types etc. As @Dovefromabove says - it may depend on what plants you need them for.
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Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
When you don't even know who's in the team
S.Yorkshire/Derbyshire border
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
As @Dovefromabove says - it may depend on what plants you need them for.
https://greenfingers.com/d246/aluminium_greenhouses
The pack of 3 traditional ones looks good
I live in west central Scotland - not where that photo is...