Light getting in

Discussion in 'First Time Marijuana Growers' started by indic4, Oct 3, 2010.

  1. I just switched to 12/12.... how important is it for them to have ZERO light get in when the lights are off? If a little gets in is that OK or does it need to be COMPLETE darkness for 12 hours?
     
  2. 12 hours of complete, uninterrupted darkness. I've heard a weak flashlight in the woods can mess up the flower cycle
     
  3. Cool, thanks
     
  4. Technically there is a low-light threshold that won't really bother the plants, but the problem is that it is such a low level, and everyone's idea of "low" is subjective, that we can't say "a little light" is OK and be steering people right. There is no way to advise how to measure the light properly. The threshold is very low, so if you allow any amount of light into your grow space during dark cycle there's a chance you are over the line. You put a lot into your grow to get a good harvest, so don't gamble with it and just light-tight everything for total darkness and then you aren't flirting with threshold.
     
  5. what about plants growing in yards near street lights?
     
  6. Marijuana plants growing in yards under street lights?
     
  7. agree, think about outdoor growing, & the moon light durning dark periods, ive been told as long as the light isnt more than what the moon would throw off youd be ok, but i still wouldnt risk it. need to work in the grow while lights out, use a green light bulb, plants cant see green light
     
  8. Basically, I want to install a passive air intake with 6" ducting that hangs out of my tent downward towards the ground. I don't think that will be an issue but I wanted to get some GC feedback. Thanks everyone!
     
  9. True that the amount of light from a full moon won't turn a plant hermie, but:

    - Humans perceive light, we don't experience light directly, so we cannot look at a full moon with our eyes and then go into a grow space and tell if it is the same amount of light or not. A full moon looks bright to us because of the contrast against the dark night sky, but in reality a full moon doesn't give off very much light.

    - A full moon lasts only a couple of days a month, a light leak presumably would be present the entire month.

    - A full moon can slow down a MJ plant's flowering pattern, but again just for a couple of days at most.

    - Plants cannot "see" green light, but you can't just use a green party bulb or green shade because, again, we perceive light, so what might look green to us probably is the result of a blend of multiple colors of light, so that "green" light could be giving off blues and reds that the plant can see.

    You have 12 out of every 24 hours where the light is on, tend to your plants during that time and leave the dark completely dark.
     
  10. So you really have a completely different question than what you first asked, which I now understand it to be: how do you get total darkness when you have intake and exhaust holes? The answer is you need light-traps, which you can easily make.
     
  11. #11 TheSabz, Oct 4, 2010
    Last edited by a moderator: Oct 4, 2010
    start getting creative with the always-handy-duct-tape and the some light suppressive material

    thanks guys about the extra information on how the plants react and sense light, i was also i bit uninformed about that part; i just love how the explanations fit rather tightly with how plants would behave in their natural surroundings
     
  12. Well, this ends up being a secondary question but yes it was different from my original one but they do tie together. Toastybiz, do you have any links to easily made DIY light traps?
     
  13. I just explained it a few days ago, look here and my additional post a few more down in that thread.

    There is a DIY section under the Grow Room Design forum here at GC, also try the search button.
     
  14. Ok Thanks, one last question: Would one 180 degree turn be as good as two 90 degree turns? Assuming that the ducting has a non-reflective inside.
     
  15. If you really need to get in there, get a LED head lamp with green LEDs
     
  16. It's not that I need to get in there when the light are off, it's more of an issue with light getting in through my passive intake.
     
  17. Yes, that works the same as two 90 turns. And you want those insides to be more than just non-reflective, you want them to be light-absorbing like flat black.
     
  18. Thanks toasty, great stuff. +rep
     
  19. I have neighbor's lights if I elect to grow them outside, and while not directly on the plants there is ambient light around. Street lights are out there too, yes, and while not directly on the plants it is out there.

    In combination with high daily temps around here (90 degrees plus during the summer), buds turn out loose and wispy when grown outside. I have since lightproofed a dedicated flowering room, so I'll see the difference a lightproof flowering room has, not temperature controlled.
     
  20. Sounds like a dream of what I would like to see growing under street lights instead of the crap thats there now.

    If you could grow plants in such close proximity as street lights you are not growing "full" optimal conditions either.
     

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