I grow HC on pure pot soil moistened there is no water above the soil just wet soil I spray every 2-3 days with a mister it grows like crazy np at all.
It is actually flowering as we speak. I use a small tank with a glass lid, it is out in the balcony. Here it has gotten really cold 2 -3 C at night but not freezing (below zero) it shows no signs of stress as yet. :P