Well last night, being a family birthday, I almost didn't go out and fleece the greenhouse, or put the flower pots in. I'm glad I did, as when Vicky and I went to the boot fair this morning there was ice on the windscreen. The cucumbers are in the greenhouse, along with all the squash and courgettes, but I covered with a double layer of fleece, and they are fine. The digital max/min thermometer gave a low of 2 degrees at the glass edge, the one hanging in the centre of the greenhouse shows 5 degrees.
At the bootfair I picked up a glass fish tank for £2, which is ideal for more of my painted lady caterpillars. I have so many, I 'potted up' 13 jars yesterday, it took me well over 2 hours. The jars that had been potted a week needed new food, so I transferred all I could find into new jars with new nettle tops pressed into the damp compost. They lasted quite well in that medium, and there are no puddles of water to drown the caterpillars. I put all the wilting leaves on the nettle bed in the woods. It is probably too cold for any missed caterpillars to survive outside, but they had more chance than in the compost bin, with no new food plants.
The picture shows a mallow leaf, covered with blue pearlescent eggs and some of the hatched caterpillars. As they get older they become black, with tiny hairs. I've been potting up nettles and mallow with small bit of root attached, hoping I've got plants before I need them for the next generation. They've probably got about a month.