Reduced hour light cycles

Discussion in 'Advanced Marijuana Cultivation' started by torontoke, Aug 9, 2017.


    torontoke Well-Known Member

    Over the last yr or so I keep reading more n more posts about people trying alternative light cycles in their rooms and rather then having the results and info scattered I thought why not start a thread.

    So if your running a schedule other then 18/6 to veg or 12/12 to flower please feel free to post your results and experiences.

    If you haven't tried anything then please skip to the next hps is better than led thread and argue there Instead.
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    WeedSexWeightsShakes Well-Known Member

    since talked to you i switched my flowering tent to 10/14 and it hasnt skipped a beat
    only saving myself 2 hours of electricity everyday
    i think veg is 17-18 hours on hard to exactly say cause it isnt a digital timer
    veg is only 72 watts anyways so i am not too worried about that
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    torontoke Well-Known Member

    Well I'm glad that your plants haven't skipped a beat but it's honestly not my intention to try to convince anyone to switch or do anything differently.
    Just trying to get as much info on the subject in one place from more then one source.

    WeedSexWeightsShakes Well-Known Member

    may not have been your intention but thanks for the savings! lol
    hopefully more will chime in with their experiences

    Doomhammer69 Well-Known Member

    I have always ran 16-8 in veg and 12-12 flower, however I am starting a dominate sativa strain Rio Negro Columbian, I'm thinking of running the lights in veg closer to what the natural day light would be in Columbia will see what happens
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    churchhaze Well-Known Member

    Since when is 18/6 standard? A ton of people use 24/0.
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    Buba Blend

    Buba Blend Well-Known Member

    I have a grow in week 6 of flower, the seedlings never saw anything but 12/12. It was not intentional. They started flowering sooner than I expected while under the 12/12. I had to transplant to 3 gallon plastic pots after flowering started another issue in the grow, but things are coming along fine so far.
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    BobCajun Well-Known Member

    23/1 for veg, the hour is to give them a diurnal photoperiod. I have a feeling that it's good to maintain a 24 hour cycle with a dark part so the plant is in a more natural environment than 24/0. Plants are evolved to be in a 24 hour light/dark cycle of some sort. To get a good amount of growth from low wattage LED bulbs I figure 21 is close enough to 24 to produce similar growth while still allowing a full hour dark period.

    For flowering it's just 13 hours until the final week, when the hours are reduced by one each day for several days until it's down to 9 or 10. I was trying 13.5 hours but didn't seem significantly more growth than 13 so I went back to that. 13.5 might drag things out too much. 13 seems just about right to me for high yield and reasonable ripening time, with the accelerated autumn at the end. I think the plants may be able to judge how quicky the days are shortening. Like they may ripen faster if it goes down by an hour per day versus 1/2 hour per day, "thinking" that they better hurry up because at that rate winter will be here like next week.
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    torontoke Well-Known Member

    A ton of people veg with 24/0?
    Beyond seedling stage I've never heard that

    rkymtnman Well-Known Member

    24/0 veg all the way. tighter node spacing, easier to maintain temps/RH, less veg time overall.

    11/13 for bloom.

    SouthCross Well-Known Member

    My light schedule.

    24 hours light for sprout stretch. About three days total of 24. Then it's 15/9 in veg. Flower start is 11.5/12.5. Reduced down over weeks to a final 10.5/13.5.

    The old standard of 24, 18/6 and 12/12 are guidelines.

    GrowGorilla Well-Known Member

    I'm a boring standard guy lol. 18/6 Veg and 12/12 Flower.

    GroErr Well-Known Member

    Currently running 18/6 or 20/4 veg/clones/seedlings and 11.5/12.5 in flower. Inspired by your thread, I knocked it down 1/2 an hour at a time in flowering to see the effects, started at 12.5/11.5, then 12/12, now 11.5/12.5 for a couple of rounds. Not seeing any downside from a yield perspective and have shaved finish times somewhere in the range of 5-10 days depending on phenos. Last 2 plants I pulled at 50 days, the one is normally a 52-55 day pheno, the other flowered as long as 60 days at 12.5/11.5. Works for me. May try 11/13 next to see if there's any noticeable differences.

    Only caveat I'll throw in here about reducing your lights on period is to have your lights-off environment in check. RH spikes during lights off so longer period could cause some issues (e.g. PM) if it's not dialled in.

    WeedSexWeightsShakes Well-Known Member

    Is there actual proof of this claim, as far as tighter node spacing and less veg time?
    Not trying to bash it just curious if there is real studies or anything to prove it.
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    SouthCross Well-Known Member

    It's all about mimicking a synthetic environment to a natural one. Tighter internodes, less veg, you grow indica dominant. Looser internode, longer veg and flower. Sativa dominant.

    The baseline evidence of what a plant will do is when it's grown outside. Replicate of that environment and how close you get to it. Determining the variables and success.

    To provide concrete proof of the performance of anything grown in a synthetic environment. Would require study of every kind of light. Grow space size, ventilation, circulation, light distance, fertilizer, temps, humidity...How close it mimics a natural environment.

    whitebb2727 Well-Known Member

    Its not really a reduced schedule but I have grown autos and vegged photoperiod under 6/2 during hotter months to keep temps down. Works fine.
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    rkymtnman Well-Known Member

    cannabis is a c3 plant so it can grow 24/0.

    any time you turn the light off during veg, the plant's response is to stretch towards the last known light source. so what people confuse as growing (it can only grow with light i.e. photosynthesis) is actually stretching.

    as far as veg time, 18/6 is 6hrs per day, 42 per week of time that a plant could be growing when it's not .

    ttystikk Well-Known Member

    I do this in veg, too. I'm very happy with the results and the reduced environmental swings.

    WeedSexWeightsShakes Well-Known Member

    So having a dark time causes it to stretch more? Wouldn't that technically create a shorter veg time? Cause it'd get to the height you want faster.
    But on the other hand if you have less dark time it won't stretch as much and keep nodes tighter? So it'd have to veg longer but end up with more, and closer, nodes?

    Is that somewhat right lol?
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    ttystikk Well-Known Member

    Funny, the horticulture professor I discussed this with said the plants will actually keep growing- not just stretching, but growing- in the dark for as long as all the basic environmental conditions are met. Those conditions include access to nutes and water, reasonable environment and sufficient stored sugars in the plant- which generally take 12-16 hours or more to deplete.

    When I mentioned the short day cycle I'm running (6 on/2 off) he said that would work fine and the stronger the light the better it would work. I didn't discuss any other lighting schedules besides 24/0.
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