Maintaining Consistant Temperature?

Hi there I use an inkbird temp controller on WiFi. I plug the extraction fan into the cooling socket and you can plug your heater into the heat socket. It isn't perfect but it's better than the fan drawing cold air all the time. Your area needs to be air tight to prevent smell. But it's worth the effort

I don't stress VPD as much as a lot of you guys. I'm not arguing against it but I don’t go out of my way to achieve "perfect VPD" either. It probably stems from all the outdoor growing I've done where you can't control environment so I've become accustomed to adjusting my grow to the conditions. Indoor my motto is if it's good enough for me it's good enough for my plants, In my basement is typically around 60-65 all the time, tent stays at about 68 and my girls are happy. If you look at most VPD charts, cooler temps generally allow for a wider range of humidity levels so it's easier to keep plants happy.

First and most obvious would be a heater or a heat mat in your tent. You can also make use of your lamps heat by switching the light hours into nighttime. It seems you have allready done that, If your grow space is on a outside wall you could try using an insulatior like styrofoam sheets. IF your humidity is right, try having your air filter only going 10 minutes per hour, to keep warmed air inside.

That's a tough one and one I always seem to have with winter grows... 68 isn't that bad... just check a VPD chart and adjust your humidity as necessary. She'll be fine! Good luck....