im wondering about this also as i currently have some plants going indoor but where it gets no heat except for from the lights. So far my temps have been any where from 28 to 80 but mostly in the 50s-60s. one thing i have noticed with this "cold" grow is i have gotten really thick stems and also lots of purple colors :hippy: but im worried about it getting colder!! i heard they dont really like it below 40 but can survive as long as their not frozen?? any thoughts guys?