Thenk you all for your tempereture figures.
There was a time when I grew Lewisia rediviva by the hundreds. I did that by using a cold frame with ventilation openings on a slope. The frame stood directly on the soil which was poor and sandy On top of that I filed a fairly nutritious mix with good drailnage. As soon as they started to die down I put the glass on. When they came back in the spring, the glass came off. i had zero losses until a mice foud a hole in the net that covered the openings.
perhaps something on these lines could help
Göte
