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Darkness before harvest
- Thread starter RosettaStoned
- Start date
DrPhoton
New member
No there is not any published data, it was likely an in house study for their benefit only. This is quite common. However its the only data on the subject and was cited with the co-operation of several parties. I would not argue its legitamacy, but i would dispute its claims without evidence.
With stored resources, once they are depleted. Thats it. All other chemical processes are a result of lack of resources and continue to destabalize. The time it takes for the type of decomposition is plant specific, some will quickly degrade while others can go weeks or months before death occurs. But the fact remains, without the fundamental properties required photosynthate production. Life or growth cannot continue. At least not in the general sense of this discussion.
With stored resources, once they are depleted. Thats it. All other chemical processes are a result of lack of resources and continue to destabalize. The time it takes for the type of decomposition is plant specific, some will quickly degrade while others can go weeks or months before death occurs. But the fact remains, without the fundamental properties required photosynthate production. Life or growth cannot continue. At least not in the general sense of this discussion.
Campesino
Banned
DANGERDAN
Just to be clear on a few points that I think we both agree on
1. THC is produced by healthy flowering plants during both light and dark cycles
2. Light degrades THC
3. Therefore, Harvest at the end of a dark period as opposed to during or after a light cycle
We may disagree about the benefits of extending darkness, but I believe we are both interested in objective knowledge rather than defending pet theories. Do you think there is any real risk in extending darkness, or just limited to no benefit? How do you interpret the SIMM findings that are floating around? You seem to be offering it as the data we are looking for, but then the theory you support goes against those "findings".
Finally, and I realize there are no tests on this either, but I plan to gradually extend the dark period to 14 hours next week (around Flower day 50). Thoughts on getting the plants to expect a longer dark cycle and how this would affect their allocation of stores? Assuming you agree with point #3 above...
Just to be clear on a few points that I think we both agree on
1. THC is produced by healthy flowering plants during both light and dark cycles
2. Light degrades THC
3. Therefore, Harvest at the end of a dark period as opposed to during or after a light cycle
We may disagree about the benefits of extending darkness, but I believe we are both interested in objective knowledge rather than defending pet theories. Do you think there is any real risk in extending darkness, or just limited to no benefit? How do you interpret the SIMM findings that are floating around? You seem to be offering it as the data we are looking for, but then the theory you support goes against those "findings".
Finally, and I realize there are no tests on this either, but I plan to gradually extend the dark period to 14 hours next week (around Flower day 50). Thoughts on getting the plants to expect a longer dark cycle and how this would affect their allocation of stores? Assuming you agree with point #3 above...
DrPhoton
New member
You and i are going to get along just fine 
Yes i agree on all three points. I see no risk, only benefits for extending the duration of dark period before harvest. You can think of it as a stage before drying and curing. As resources are broken down for the fight for survival.
The SIMM results if taken to be accurate, suggest only what i would have thought happens during the night cycle. Growth. Its been shown that plants grow during the night, simple time lapse videos demonstrate this when the dark phase is removed from the recording and a sudden jump in growth is seen. In fact, growth can be more at night than during the day. Which was suggested in a study on pumpkins? i read. Although SIMM chose 72 hours, this does not mean the same results could not be acheived at 12 hours also. As they did not choose more sample points we cannot know, but i trust the research i cited earlier and my own understanding of plant biology and chemistry.
What is your reason for extending the dark period ? I assume you still keep 24 hour days and as such sacrifice two hours of light for the lights on period. Changing the light cycle effects the maturation and yeild of the flower process. From the research article i cited earlier, it suggests that the storage and utilization of starch changes with respect to its environment. If there are light and dark conditions that change, so will its storage capacity and level of degradation for the dark phase.
Yes i agree on all three points. I see no risk, only benefits for extending the duration of dark period before harvest. You can think of it as a stage before drying and curing. As resources are broken down for the fight for survival.
The SIMM results if taken to be accurate, suggest only what i would have thought happens during the night cycle. Growth. Its been shown that plants grow during the night, simple time lapse videos demonstrate this when the dark phase is removed from the recording and a sudden jump in growth is seen. In fact, growth can be more at night than during the day. Which was suggested in a study on pumpkins? i read. Although SIMM chose 72 hours, this does not mean the same results could not be acheived at 12 hours also. As they did not choose more sample points we cannot know, but i trust the research i cited earlier and my own understanding of plant biology and chemistry.
What is your reason for extending the dark period ? I assume you still keep 24 hour days and as such sacrifice two hours of light for the lights on period. Changing the light cycle effects the maturation and yeild of the flower process. From the research article i cited earlier, it suggests that the storage and utilization of starch changes with respect to its environment. If there are light and dark conditions that change, so will its storage capacity and level of degradation for the dark phase.
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RosettaStoned
New member
Another question, since I have one ready and I am putting in the dark. Are there negative effects to the other two, which go into flush tonight, being in the dark longer?
Campesino
Banned
Yes, I keep my own time-lapse and it is very clear that they grow at least as much during the dark.
Based on all that I have read and understood, it seems unlikely that a flowering cannabis plant needs a 12 hour photo period in order to do all that it needs to do. Since THC degrades under light, I don't want to give them more than they really need to recharge their reservoirs and keep producing. Furthermore, this more closely resembles natural light cycles with night time increasing as the plants mature. If they are better prepared to handle then at least 14 hours of darkness it seems that could also help power them further through the dark period (At least 2 hours further ). Based on what you've said, wouldn't it be better to have a plant trained to grow in the dark for a longer period of time just prior to harvest?
Based on all that I have read and understood, it seems unlikely that a flowering cannabis plant needs a 12 hour photo period in order to do all that it needs to do. Since THC degrades under light, I don't want to give them more than they really need to recharge their reservoirs and keep producing. Furthermore, this more closely resembles natural light cycles with night time increasing as the plants mature. If they are better prepared to handle then at least 14 hours of darkness it seems that could also help power them further through the dark period (At least 2 hours further
). Based on what you've said, wouldn't it be better to have a plant trained to grow in the dark for a longer period of time just prior to harvest?
RosettaStoned
New member
I flush for a week, so I will need to turn the light back on.
Campesino
Banned
Yes, don't extend the darkness on plants until you are ready and willing to kill them. It probably won't kill them outright, but it won't be good for them if they still have a ways to go. In your situation it is best to harvest the one that is ready right before the lights come on. If you can pull the plant and keep it in the dark elsewhere that could be another option. You can extend the darkness on the last plants that are ready.
RosettaStoned
New member
DrPhoton
New member
The problem there is that changing the light cycle to have more dark than light, promotes faster maturation but less yield.
Any benefits you feel might come from it, would certainly be outweighed by the fact that you provide overall, less light. Wether the night is longer or shorter, the starch reserves are almost completely gone before the night phase is over. Because you try make the reserves last longer does not increase production because of more time, the growth is dictated by the total energy not the time the energy is given to do work.
From my personal research on light cycles, i have looked at what possibilities are viable with light manipulation. The only real difference between them is how much light is provided and how that energy is utilized. The famous 18 vs 24 hour lightcycle debate still continues, because there is not any substantial differences to conclusively state which is superior. And no side by side evidence. The fact of the matter is however, that it has been looked at the wrong way.
The only real difference between 18 and 24, is the total amount of light provided and time. During the vegetative stage, light cycles that have more light than dark, just grow quicker. The cycles with less light takes longer. But at the end of the day the same energy is used. Only the time it takes to reach the desired growth state has changed. People have been looking at it from a yield standpoint, rather than a yield/watt/time aspect. Also this is only applicable to the vegetative stage with photoperiod plants. By the time you reach the flowering stage, you have to adopt the flowering light cycle. Which would ultimately dictate yield and is used regardless what you were using in the veg stage.
I will choose 18/6 or 20/4 over 24/0 because the only thing you loose is time. As i have said the only two things that differ between light cycles, is energy provided and how that energy is used. Circardian rythem, photomorhogenesis, photorecepter proteins and more, have an effect on plant morphology. Which i argue are far more impactful when night cycles are used. Using light cycles without any dark can only have the benefit of faster vegetation. But because results are always so inconclusive, it may be suggestive that cycles without any dark, do not utilize the energy provided as efficiently as one that does include a dark phase. So you run the risk of wasted power for the same result.
Autoflowers on the other hand is possibly a true viable place for 24 hr cycles, as the maturation time is dictated by genetics. As far as i know anyway, i believe the flowering time is not influenced by light cycle but a genetic clock rather than a environmental clock such as with photoperiods. If this were not the case then 24hr cycles with autoflowers would take much much longer to finish. But again, all you save is time. Compared to photoperiods, the quantum yield of photosynthesis and electrical efficiency and efficacy is unchanged. Assuming all other variables are unchanged.
Any benefits you feel might come from it, would certainly be outweighed by the fact that you provide overall, less light. Wether the night is longer or shorter, the starch reserves are almost completely gone before the night phase is over. Because you try make the reserves last longer does not increase production because of more time, the growth is dictated by the total energy not the time the energy is given to do work.
From my personal research on light cycles, i have looked at what possibilities are viable with light manipulation. The only real difference between them is how much light is provided and how that energy is utilized. The famous 18 vs 24 hour lightcycle debate still continues, because there is not any substantial differences to conclusively state which is superior. And no side by side evidence. The fact of the matter is however, that it has been looked at the wrong way.
The only real difference between 18 and 24, is the total amount of light provided and time. During the vegetative stage, light cycles that have more light than dark, just grow quicker. The cycles with less light takes longer. But at the end of the day the same energy is used. Only the time it takes to reach the desired growth state has changed. People have been looking at it from a yield standpoint, rather than a yield/watt/time aspect. Also this is only applicable to the vegetative stage with photoperiod plants. By the time you reach the flowering stage, you have to adopt the flowering light cycle. Which would ultimately dictate yield and is used regardless what you were using in the veg stage.
I will choose 18/6 or 20/4 over 24/0 because the only thing you loose is time. As i have said the only two things that differ between light cycles, is energy provided and how that energy is used. Circardian rythem, photomorhogenesis, photorecepter proteins and more, have an effect on plant morphology. Which i argue are far more impactful when night cycles are used. Using light cycles without any dark can only have the benefit of faster vegetation. But because results are always so inconclusive, it may be suggestive that cycles without any dark, do not utilize the energy provided as efficiently as one that does include a dark phase. So you run the risk of wasted power for the same result.
Autoflowers on the other hand is possibly a true viable place for 24 hr cycles, as the maturation time is dictated by genetics. As far as i know anyway, i believe the flowering time is not influenced by light cycle but a genetic clock rather than a environmental clock such as with photoperiods. If this were not the case then 24hr cycles with autoflowers would take much much longer to finish. But again, all you save is time. Compared to photoperiods, the quantum yield of photosynthesis and electrical efficiency and efficacy is unchanged. Assuming all other variables are unchanged.
Campesino
Banned
Fascinating conversation... Agree with everything you said about Veg. The time to harvest is a compelling reason for some commercial growers I am sure, but giving them a little dark period can't slow them down much and I want time to be in there training etc. I am starting seedlings 24/0, but I'll put them on 20/4 or 18/6 as soon as they are in the tent. I certainly don't respect the darkness of the dark cycle during veg though.
Nebula's article that you linked deals mainly with yield and doesn't advise against switching to longer nights, just recommends doing it later than I had planned. I think I will follow that - Thanks! In RosettaStoned situation, it seems the plants would be fine with longer nights as we are worried more about potency than yield on the last few days. But I am interested and I am sure Rosetta is as well in your thoughts on his situation (below in the thread)
Nebula's article that you linked deals mainly with yield and doesn't advise against switching to longer nights, just recommends doing it later than I had planned. I think I will follow that - Thanks! In RosettaStoned situation, it seems the plants would be fine with longer nights as we are worried more about potency than yield on the last few days. But I am interested and I am sure Rosetta is as well in your thoughts on his situation (below in the thread)
Locrian99
New member
I can’t be 100% but one of my gg’s that I put through a dark cycle about 60 hours had what I’m about 90% certain were bananas following the dark cycle that I did not see before. It was previously stressed during flower (mites/ph issues). I have not found any seeds in it either so far which makes me also think they showed up at the end. Not sure if those would form in the dark though.
RosettaStoned
New member
We will see what happens. The ones I'm waiting on I grew right before this. I should have a pretty good idea if there was a negative/positive reaction.
I don't think the 10/14 schedule will do much harm. The light at the end of an outdoor grow is probably that, or close.
I don't think the 10/14 schedule will do much harm. The light at the end of an outdoor grow is probably that, or close.
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DrPhoton
New member
I see where you are coming from, quality vs quantity. Seing as its at the very end of maturation, the yeild effect may be minimal. As to the quantitiy of THC, that would really depend on the desctruction vs production rate of THC. Which we know very little about. We have to assume that production of THC is faster than the destruction, otherwise that would imply the majority of THC is developed overnight. If we also take the evidence from SIMM to be correct, one could argue that shorter flower light cycles produce more trichs than longer light cycles. But take the results in context, they said SOME strains and UP to 30%. It would likely be that the majority of the results were much, much lower. Whatever benefits there are from harvesting after dark, i believe they would be a result of the leftover unsued energy that would otherwise be wasted and unutilized if done before dark.
Just to top it off also, autoflowering strains typically are grown under longer light cycles than photoperiods. But they still develop frosty trichs. Autoflowers would be the best place to test such a theory. You could play with the light cycle more during flower.
Just to top it off also, autoflowering strains typically are grown under longer light cycles than photoperiods. But they still develop frosty trichs. Autoflowers would be the best place to test such a theory. You could play with the light cycle more during flower.
Campesino
Banned
I just mean that I go into the tent and work during the time lights are off during Veg. I use a cfl to illuminate the tent while I'm in there. During flowering, I respect the darkness, and give them 12 hours uninterrupted. That means I have to take my time in the tent at the beginning and end of light cycles, essentially robbing light time from the plants.
Campesino
Banned
BTW DANGERDAN I think we have arrived at near perfect agreement. I appreciate your input and knowledge.
I also hope that funding becomes available so this research can be done in Universities and elsewhere. There are so many testable hypotheses when it comes to growing indoor cannabis and it is certainly a growing market. Probably (hopefully) just a matter of time
I also hope that funding becomes available so this research can be done in Universities and elsewhere. There are so many testable hypotheses when it comes to growing indoor cannabis and it is certainly a growing market. Probably (hopefully) just a matter of time
RosettaStoned
New member
To avoid this in the future I'll grow the same strain.