Tunnel cloches

Fleece will tear easily in the wind and shed plastic fibres everywhere. Thermacrop is good for taking the chill off in early spring but it's not going to provide much protection against a hard frost, and thought stronger than fleece is still quite fragile. Polytunnel plastic would be my choice as it will provide the best heat retention and protection from cold winds, but on a sunny day will overheat if not vented.

I usually start my early potatoes in pots in the greenhouse, but now we're growing in the borders all year round there is no space to put the pots. Last year I kept them outside covered with a quadruple layer of enviromesh and it worked fine, though we didn't have any frosts anyway.