Here's the thing I don't quite understand about temperature: I read everywhere that 75 degrees or so is optimal. I also read that you can put your light real close and as long as your hand doesn't burn after a minute, your plants would be fine. So my hand can withstand temperatures way higher than 75 degrees! This seems like conflicting info--can anyone clarify?

Apologies if these seem like dumb questions. I have spent lots of time doing lots of research, but some stuff just doesn't seem to add up.