Definitely consider head space just as FF said. That's why I went for a 6.5'x6.5'x6.5' tent. I am going to keep my ladies at roughly 2 - 3.5' depending on strain. Hope to upgrade my dinky 400 to 1k soon. Depending on where you live, humidity is going to be a problem. Unless you have some good ventilation going on. Having a tent is perfect to do a sealed grow. Have an ac, dehumidifier, cool your lights independently (intake from outside of the tent and exhaust outside of the house), co2 system.
I keep my humidity under 30% pretty much all the way trough since I use that tent solely for flowering. I try and hold it at 20%. Molds have virtually zero chance of holding with that humidity and it doesn't seem to bother the girls. If your hydro, try to cover up any expose water.
so what you think? gonna join us tent growers? :hi:evilgrin