Idea sent-in by Steve (Cambridgeshire)- April 2011.
As I don't have a full size greenhouse in my garden, I have used plastic greenhouses and cold frames for many years and with much success, to protect young seedling and plants, during late winter and early spring. The only drawback has been that they are difficult to protect from frosts on really cold nights as you can't put a heater in them.
This year I managed to obtain a really small one, which is only 69 cm x 49 cm x 1.25 m (that's about 3.5 ft high by 2 ft wide for us old school types). I noticed they had them on at a special price in the local garden centre for just £10 each, but I did not buy one initially as I thought it would be too small for my needs. However, some friends of ours bought one but decided they did not have room for it (which is surprising given the small size!) so they very kindly gave it to me
It was simple to put-up, only taking me about 10 minutes and very sturdy for its size - some of the larger ones I have used in the past would often fall apart as the fixings were just simple push fit - but this one is secured with screws.
Anyway, it turns out to have been one of the best garden accessories I have ever used. Due to its compact size and sturdy design, it can be lifted and moved even with some of the plants still inside (if lifted carefully from the bottom). And best of all, it fits very neatly inside our patio doors! Which means that at night I can simply lift the whole thing inside and close the door.
I have been bringing it in at night and putting it out during the day for the past couple of weeks and the plants just love it. Now that the weather is warming-up I can leave it out on warm nights and just bring it in when frosts are forecast. Of course you will need to place it on a rubberised mat to catch any water drips from the plants.
However, you need to be careful in windy weather as these mini greenhouses are so light they can blow away, so it pays to put something heavy in the bottom to weight it down when they are outside. In fact when its very windy I just leave it inside with the blinds open.