I think maybe the bubble wrap could help insulate it during an extra cold snap, but it would be a lot of work ... and of course it would always be short term, especially if it was the only covering on the top - whether its about damage from the weather, or even a cat jumping on top of it to see what's what! Hmmm ... I think my plan to experiment with bubble wrap on the top of a cold frame had better go back to the drawing board!
I've seen the little greenhouses with a plastic cover - they look like real space savers, great choice. I'd want it against a house wall, though, rather than freestanding, and I don't have anywhere where it would fit.
Its a really good point about opening and closing the cold frame top as appropriate - I know greenhouses can have a solar-powered vent, though they're quite little. For me, since I work from home, I could do it myself, but if you work outside the home for any length of time at all, it could be a real problem.
I've seen the little greenhouses with a plastic cover - they look like real space savers, great choice. I'd want it against a house wall, though, rather than freestanding, and I don't have anywhere where it would fit.
Its a really good point about opening and closing the cold frame top as appropriate - I know greenhouses can have a solar-powered vent, though they're quite little. For me, since I work from home, I could do it myself, but if you work outside the home for any length of time at all, it could be a real problem.