thanks for straightening me out fellows. I'm only one zone warmer that you Eckhard and we grow palms outside and even have two native species. We grow a lot of agave species and cacti also outside unprotected. We have had 5f a time or two in the 25 years that we've been here but usually only low teens f for a very short time. Am thinking that daylight hours may make a big diffence also. Am at the same latitude as Santa Barbara California so you can get some idea of daylight hours in winter here on the opposite coast.