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Only using 8 hours of light for flower? instead of 12/12

Discussion in 'Indoor Marijuana Growing' started by DanMan420, May 30, 2011.

  1. Ok, so here is the deal. I've done a few crops and know my lighting and stuff, but one of my friends does and has a pretty decent grow only flowering for 8 hours a day. He does this to keep his energy bill down, because he runs a 1000 watt. not that smart of a plan, but I was thinking.

    I have been running a 250 watt for 11 1/2 flower cycle, I want to start running a 400 watt on a 8 1/2 cycle so the utility cost would stay about the same. but I'd get more lumens... idk. any input?

    I normally wouldn't consider this, but after thinking about it, maybe this could work, if you took a plant from 16/8 to 8/16 wouldn't it automatically think it was deeper into fall, or deeper into flowering?
  2. Stay with the 12/12. Cannabis only needs 12 hours of darkness to put it into the Flowering stage. Therefore, although your friend is saving money on the power bill he is limiting the amount of growth that normal plants would receive.

    It is okay for 8/16, but not Optimum. When growing for quality and high yields you want Optimum conditions which this is not it.

    During veg 20/4 and 24/0 are acceptable because they do not need the dark period during veg.

    During Flowering they must have at least 12 hours of darkness. I have heard of doing 13/11, but I would never want to risk allowing my plants to 'Re-Veg'.
  3. For me I start with 24/0 for my seedling...when my seedling starts to develop 2-3 leaf sets I switch to 20/4 until flowering then I go 12/12. Late flowering, i'd say the last 4 weeks I take half hour off every other week which amounts to an hour so that my light schedule towards the end is 11/13 - light/dark

    I agree with Hobby. starting off with 8 hours of light in flowering in my opinion is detrimental because the plant isn't able to store enough light energy to give to the buds in dark...

    I would rather diminish my light slowly along the continuum of the plants life...especially if i'm gonna give 36 hours darkness before chop.
  4. ^This. He is saving maybe $30 in electricity over the entire flower period and ending up with less bud (bud that is worth $300-$400 an ounce). So it's penny-wise and pound-foolish.
  5. So how about 8/16 during the last two weeks of flowering???? Anybody?
  6. Why deprive your plants of extra time with the light on, when growth is possible? I don't even agree with working your light system down a gradient.
  7. To make plant to "think" that death is knocking on the door , but plant is still not pollinated so it try to produce more resin. Again this is all theory... I was just wondering if anyone done it with good results .

  8. Isn't that what the 36-48 hours of darkness before the chop is for though?
  9. ^That is the theory, yes.
  10. I also heard of bumping the lights up to 14 hours a day for the last couple days of flower to increase yield... I just remember reading it off a form on here a while ago. Any ideas?
  11. If you maintain the 12 hour dark period, you can do 14-16 hours of light. There's a dude on youtube that recommends it and he's got a shit ton of plants in the video, so the dude totally grows decent bud.

    I'm lazy, I just give them a few extra days... :smoke:

  12. lol, just do a 12/12 for flower!! if you're so worried about saving a few pennies, buy weed from someone, and leave the growing to someone else.....
  13. Quit messing around with the photoperiod. Set them for 12/12 and enjoy the results. People who think changing the photoperiod for a few days at the end of 8-14 weeks flowering times will make any significant difference in the resin count or the size of the buds are only fooling themselves.

    There is no physiological reason in the growth of the plant to expect these anecdotal methods to increase the quality of the flowers in the last few days of the flowering cycle. Grow a strong and healthy plant and you will be well rewarded.

  14. OP you don't wanna cut down on your light period!

    since most cannabis will flower with 12 hrs of darkness you don't want to give it any more of a dark period than that! why? you want them to get as much light as possible while still being able to flower...this way the plant will grow to its maximum potential.

    Its ok to use less than 12hrs light if suggested by the breeder (some strains love less than 12hrs of light in the last two wks...like most white widow varieties).

    i personally grow like this: 18/6 for veg...24-48hrs darkness...then flower at 12/12. then i give 48-72 hrs darkness before the chop.

    i put them in the dark for 1-2 days from veg to flower to give them a kick start. ive noticed that i actually see hairs a few days quicker with that method versus just going from 18/6 to 12/12

    i put them in the dark for 2-3 days right before harvest to milk them for every bit of resin/thc goodness they can produce ;)

    im growing out a white widow right now and they suggest to give it only 8 hrs of light in the last wk or two...this will be the first time i give less than 12 hrs of light for flowering but only because the breeder suggests doing that..

    other than that just stick was 12/12 and give them the best chance to give you a good harvest.
  15. #15 Jellyman, Jun 2, 2011
    Last edited by a moderator: Jun 2, 2011
    While I agree that 16hrs is certainly way too much, at least some strains can flower more robustly when given a little more than twelve hours of darkness. I've seen plants repeatedly yield more when given up to 13hrs of dark. It's not a huge difference but it's definately there with some strains. To be fair, I've also seen different plants yield the same with 13hrs as with 12.

    There's even more reason to have at least a half hour of extra darkness when using HID's, because they continue to glow for awhile after being turned off.

    I always flower under 12.5/11.5. If I had more time and resources, I'd try each new strain under different lengths of dark periods to find its most ideal setting.

    Post #420 :yay:

  16. this is a great idea although 8/16 is a bit extreme. on sativas i cut it down to 11/13 or 10/14 cuz , naturally, they are on the tropics and need that extra kick to fully finish flowering or it will just keep making new calyxes.
  17. time to test the theory myself
  18. What I think would be best would be to simulate its real conditions. Weed thrives in the wild.

    Start out at at 20/4 then gradually increase it by 10 minutes a day until you are at 22/2. Leave it like that a week or 2.

    Then start taking about 10 minutes out a day until you are down to 12/12.

    Once you are there, maybe start taking 5 minutes out a day until you are ready to chop her down.

    Each day it get's less and less light, she knows her end is coming soon. With the lights the same, she thinks she lives like in the equator.

    Hope it makes sense, d;x
  19. Have you tried this theory out steve?
  20. thats a dumb idea indoors. it makes your plant grow alot longer than necessary

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