Advice for winterizing this grow setup

[Ray]

An advantage of the humidity tent is that water in pots and trays is plenty to keep the RH up, without added devices, and the heat from daytime lighting creates a nice diurnal fluctuation.

Before I moved to NC, my plants were in such a setup, in a dehumidified, unheated basement with about a 15-20% RH. Inside the tent only dropped below 75% when I had the flap open.