i lost some of my plants because it was around 31f at night and they froze whats the coldest they can get with out this happening?
i've heard it shouldn't go below 40 at night at least and from the sounds of it your climate is currently too cold to be growing right now (anything below 32 will kill your plants for sure because they'll freeze)
i live up in mn and my plants last year went through 2 or 3 frosts, and did fine, you just need the right genetics. it was bomb shit too (island sweet skunk)
Indica is from the high cold mountains and can handle freezing weather.Sativa is a tropical strain and can't handle it unless the plants are big and have a deep root.I grew some sativa plants through the middle of December,they looked like shit,but they survived till then. It usually freezes here by the end of October,so letting a plant go till December was really pushing it.