below -60 I once grew plants in Antartica and then won the Cannabis cup serious 2008. The buds were humungous... Best weed I've ever smoked. Make sure you plant them where they get really cold they will grow alot better. and if they stop growing and look like their dieing just let them go theyre just hibernating and if you don't look at them the buds will magically appear good luck
And here I am shittin over 3 55 degree nights in california..lolThey can take a pretty big shit kicking,,i live in the rocky mountains of canada and grow outdoors every year,have had 2 below zero nights already and at least four frosts this year. They are still happy healthy and growing. Last year they survived a couple days with rain snow mix.