I have a 5' Carnegiea gigantea and 3' Pachycereus pringlei and was wondering if running a strand of old (non-led) Christmas lights around each during winter would provide enough warmth.

We normally do not see temps in the 20s, and if we do it's only for a few hours.

Would we need to put freeze cloth over the Cacti as well during freezes, or would dense lights by themselves be enough?

Actually wouldn't mind just leaving the lights on the Cacti during winter and have them come on each day on a timer.

Would really appreciate your thoughts :)

Thanks,
-Peter