Originally Posted by kay

Possibly a cold shock if the nights in your mini greenhouse are colder than the conditions they've been growing in previously. It's getting a bit warmer, so they should recover OK. If it is because of cold, next year introduce them to it gradually, bringing them in at night for a while, for example.

I grow mine up canes - takes up less space, allows the cucumbers to hang down freely. They have self-clinging tendrils, so if you gently and loosely tie the stalk into the cane, they soon get the idea.