Ground frost is bad, just like a water pipe when the water inside the root freezes it expands and busts the root structure, thus leading to death, also causes moisture in the bud which can promote bud rot
you guys are talking about hard frosts. as i understand it, there are quite a few strains that even require a good frost or two before they are fully finished to maximum awesomeness.
never heard of plant fleece either,whats that shit about?! I don't get up NEARLY early enough to take the coverings or whatever off so whatever i do has to be sun friendly....
just depends how bothered about your plants you are.
do you have the internet.
type in plant fleece.
and if its frosting then maybe move indoors?.
fucking about with the temps could stress the plant and send it hermie.