Old thread here I know, but it gets asked weekly, so here......spread this around.
Thru my own experience, my babies curled up with too much light and humidity under 25%. Now with 2 humidifiers dropped in plastic 5gallon totes, I keep 2- 18" fans on and the humidity stays around 60-70%. The room is 8x6x6 w/a 1000w mh burnin', and a 1350watt space heater. I figure that if the air smells and tastes like a forest, the veggies will flourish. I'm going to slowly lower it in flower and maintain about 30-40%. Last week, no water and as dry as i can make it! Hope this helps.
stay below 40% to dry. I haave no idea why people cant just answer a question. Quoting scripture? Are you kidding? I personally spay(foliar feed) throughout until about week 6 of flower. I run about 40% then. I had an issue once @ 45% end of flower but I do spay them. Fans and good air movement are key. If you cant get a high % in veg just spray them a couple times a day. I'd wouldnt recommend in flower unless you know what your doing.
The best temp for vegging and flowering is 65-75 degrees. And humidity for veg is 60-70% but be sure not to go over 70% cause it can cause mold and bacteria to feed on. But for humidity in flowering you can lower it to the 40-60% range.