Saintpaulia update.... my experiment seems to have worked. All three have new roots and seem to holding well. I will give them a couple of weeks to establish before moving them to their permanent home.

High Temperature:
Actual: -6°C cloudy flurries .30cm Wind W25km/h P.O.P.66%
Average: -2°C
Record: 13°C in 1944

Low Temperature:
Actual: -7°C cloudy Wind W24km/h P.O.P.44%
Average: -10°C
Record: -29°C in 1939