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Thread: Changing light cycle

  1. #1

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    Default Changing light cycle

    Anyone screw around changing to 12/12 from 18/6 once flowering gets moving?

    I'd like to flower a couple photos that are almost ready to flip (10 days) and my auto is in gear now. The auto 'goes to sleep' 4-5 hours before 18hrs as it is now.

    Anyone want to share an opinion?

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    Everything I have ever read suggests that this would impact on yield
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    Quote Originally Posted by M_C View Post
    Everything I have ever read suggests that this would impact on yield
    I figured I couldn't find anything specific to my situation. Thing that makes me think it could work is that the plant seems unhappy with the hours of light It's getting.

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    I had mine on 12/12 for a few weeks because I had to flip my photo, my autos where low yielding strains anyway but I think I still pulled around a oz a plant (4 total) then 5 from my photo about 5-6 weeks later....100% know the autos would of done a hell of a lot more, I think I ended up losing around 300 light hours that the autos would of benefited from

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    Quote Originally Posted by sourshoes View Post
    Anyone screw around changing to 12/12 from 18/6 once flowering gets moving?

    I'd like to flower a couple photos that are almost ready to flip (10 days) and my auto is in gear now. The auto 'goes to sleep' 4-5 hours before 18hrs as it is now.

    Anyone want to share an opinion?

    sent from space
    Going to sleep can be a sign of too much DLI. Reduce ppfd or hours to work out what bottleneck is

    You can increase ppfd and reduce hours to 12/12 and you would not losing as much as you think.

    Theres people pulse driving leds now so the plant receives many (lethal) thousands of ppfd for short durations. Plants are happy and yields are up.

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    I have done it to a Jack Herer before going from 12/12 to 12/24. Worked out badly for my plant, but the blurb on the net seem to say that the yield is not affected.

    Just my guess but for the funky light hours to work is probably strain dependent.
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    Quote Originally Posted by Valentina View Post
    I have done it to a Jack Herer before going from 12/12 to 12/24. Worked out badly for my plant, but the blurb on the net seem to say that the yield is not affected.

    Just my guess but for the funky light hours to work is probably strain dependent.
    Is that 12 on 24 off so a 36 hour cycle? Seen lots of something for nothing claims on internet too.

    I would guess the yield would reduced by 33% but the consequence of rewiring its clock may have had other negative effects too.

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    Quote Originally Posted by gardro View Post
    Going to sleep can be a sign of too much DLI. Reduce ppfd or hours to work out what bottleneck is

    You can increase ppfd and reduce hours to 12/12 and you would not losing as much as you think.

    Theres people pulse driving leds now so the plant receives many (lethal) thousands of ppfd for short durations. Plants are happy and yields are up.
    That's what I thought. Its under the HLG100 and at 28". I could lower it and move to 12/12 when my photos are ready ina. Couple weeks. Cant go much higher.. Maybe a few inches

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    Quote Originally Posted by sourshoes View Post
    That's what I thought. Its under the HLG100 and at 28". I could lower it and move to 12/12 when my photos are ready ina. Couple weeks. Cant go much higher.. Maybe a few inches

    sent from space
    A few assumptions here but here goes

    If going from 18 to 12 hours you are at 66% accumulation if ppfd remains constant. You therefore need to increase the ppfd by x1.5 to maintain photoaccumulation as before

    1 over the square root of 1.5 is 0.82 or 82%

    82% of 28 inches is 22.96 or 23" between friends

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    Quote Originally Posted by gardro View Post
    A few assumptions here but here goes

    If going from 18 to 12 hours you are at 66% accumulation if ppfd remains constant. You therefore need to increase the ppfd by x1.5 to maintain photoaccumulation as before

    1 over the square root of 1.5 is 0.82 or 82%

    82% of 28 inches is 22.96 or 23" between friends
    You're the man. I'll leave them and when the photos are ready I'll shorten the daytime and lower the light (2 weeks) and they should br well ln their way.

    I'll make a note today when they start drooping. Its well watered so today will be a good judge. I have to think part way through flowering the loss in yield will be less than if I dropped to 12/12 at first sign of flowering.

    Thanks for the math

    sent from space

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    Look at this.. Only 13.5hrs in . earlier in the day for reference.

    sent from space

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