humidity and temperature

[tom thumb]

Hi, I've been reading how a lot of people are tracking humidity quite closely, i realize the benifits of keeping humidity down for prevention of molds and pests, is this more important for growers not using "soil" or is it just as important? I have a dehumidifier and have the room between 50 and 55 % humidity is this ok for the whole grow? also i've seen people refer to res. temp. what is this? i understand rh is relative humidity but can't figure out the temp one. also i am using a cool tube and i am wondering if your cooling air comes from outside, in the winter when it's extremely cold (minus 30 C) will the cold/hot conflict in the tube damage the light or cause condensation? Just an FYI, I'm two days into my first properly set up indoor grow, and I cannot believe the changes in the plants in two days, my gosh why are farmers still growing crops outside?

 

[Hick]

"res temps" are speaking of reservior teperatures of "hydroponic" grows.. water farmers..