Yeah, come to think of it I'm thinking of plants in the ground which absorb a lot or radient heat. Container plants probably should come in when it dips into the 40s but I doubt the high 40s would kill them. Tepin plants here manage tolive through several freezes a winter but of course they are native...not tropical like habs. My habs have survived temps just below 32º when I put sheets over 'em.