I just got a new ballast/reflector and 400 watt MH and HPS bulbs for my upcoming grow. Up until now I have used cfl's and gone 24/0 light cycle for veg. Now with MH I am going to go 18/6. My question is, do I need there to be absolute darkness in the room during the 6 hours of darkness similar to the 12 hours during flowering?
its not as important during veg, i have a dark closed flower room and a realitivly open veg room...i,ve never had a problem but i'm using exclusively female clones from mother plants...but it does stress the plant out if it gets to much light at dark time and anything that stresses the plant creates chance for hermies...
Thanks! I will most likely keep it sealed off, but my setup doesn't have the best ventilation, and there isn't much I can do about it aside from keeping the closet door open. I was thinking of not sealing up all the cracks so there was more room for air to come in during veg, even though it would leak in a tiny bit of light. Ventilation will be a full time battle for me.
It's been pointed out to me in the past how difficult it is for this to translate over the net so please take this with a grain. . . I try for nature. I have a tried method that works for me as far as light leaks go. I compare what I know - how the skin on my arm looks in full moon light is the absolute brightest it can get during my dark cycle. It's not scientific but if you have a cheap grow and aren't too worried about 100% ideal circumstances I have found this works for me.
Mirvs may indeed have a way to tell accurately what is "under the line" in terms of amount of light, but it really isn't something that most people should be trying to judge for themselves. How much is too much? The answer is that it depends, and the safest approach to preventing hermies is to give the plants complete darkness during dark. As others have said, it isn't as important in veg, but it will be very important in flower so you might as well get your grow op light-sealed now.
I can easily light seal my op, as I've done so before. My problem is moreso with ventilation, which I could make better if I didn't light seal it during veg. I probably will light seal it and just keep the door open during the light cycle. Just figured I would check to see if it needed full on darkness, because if it didn't I would keep the door open all day.
If you are relying on non-light-trapped openings for ventilation then they are much too big for maintaining dark. If we are talking tiny cracks then it won't be a factor in ventilation, and if we are talking about openings large enough to contribute significantly to ventilation then they have to be light-trapped to maintain dark.