Any marijuana grow room set-up suggestions?

A inquiry from a fellow grower:

I live in a colder climate. Around freezing or slightly lower in winter and around 20°C or slightly higher in summer. According to reports the relative humidity where I live is around 80% outside but my barometer suggests an average of 50% inside.
I was thinking about trying to grow in my attic in a grow tent.Then I run into HPS vs T5 lights and various other questions.
I am hoping that there may be someone there that can give me some answers or suggestions concerning Lights, Nutrition, and other questions I have so I don’t start off on the wrong foot.

to many variables in the attic ,in my opinion …do you have a closet you can grow in or grow tent in a room will work better ?

There are many many things that can go into deciding how to build a grow room, the attic may be just fine as long as you can control the environment. I think researching in the free e-book here and here on the blog and guides will help you make good decisions.

If you have more specific questions feel free to come back and ask.