earthwyrms
Active member
what about 21-23/13 light/dark cycles?
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21/13 23/13 light cycles?
- Thread starter earthwyrms
- Start date
I got really interested in the theory behind longer or shorter photoperiod and their effect. I have not experiment with it and hence everything I am about to say comes from different forum and internet sources and should be considered unconfirmed. However different posters on different forums came with the same results.
Basically, it seems if you go lower than 12 hours of light (ex. 8/12) the plant sees more than 7 days in a standard week and will finish its flowering cycle faster than a if it was on 12/12 yet the yield will also be reduce (Yet I am not convinced the reduction is suboptimal if you consider shorter flowering cycle means more harvest a year so it could still beats standard 12/12 in yield per year and in my book that would mean it is better).
On the other hand, people experimenting with 14/12 or 16/12 would report a longer flowering cycle and an increase in yield. I do not think however that the increase was linear with the amount of light. For instance, going 18/12 would mean a 50% light increase but I think the concensus was you would get less than a 50% increase in yield. Yet again, it represent in the total lenght of the cycle a minor augmentation of time (28 hours days instead of 24 hours which translate as a 16.6% increase in flowering time, for some, as long as the increase in yield beats 16.6%, it is worth it.
There is some interesting information in this thread : https://www.icmag.com/ic/showthread.php?t=156499
Look for the posts by blckbrd, LJB and secondtry
secondtry did experiment with very long days (24 hours + if memory serves) and he would give one hours of light off during that time to give some rest to the plants.
Finally I remember reading about this guy who would go 12/12 but every 3 or 4 days he would leave his lights on for 24 hours instead of 12 (Basically reversing night and day) without the reveging or the plants going hermies. He was convinced it improved his yield.
I am confident there is a lots of knowledge to gain from experimenting with different photoperiods and that it is the next step to improve optimal yield conditions. I guess it also depends what matter most to you. Electricity usage, time till harvest, all the above, etc. I am sure people around ICMAG have exeperiment with this one way or the other. I'd be curious as well in there results.
Basically, it seems if you go lower than 12 hours of light (ex. 8/12) the plant sees more than 7 days in a standard week and will finish its flowering cycle faster than a if it was on 12/12 yet the yield will also be reduce (Yet I am not convinced the reduction is suboptimal if you consider shorter flowering cycle means more harvest a year so it could still beats standard 12/12 in yield per year and in my book that would mean it is better).
On the other hand, people experimenting with 14/12 or 16/12 would report a longer flowering cycle and an increase in yield. I do not think however that the increase was linear with the amount of light. For instance, going 18/12 would mean a 50% light increase but I think the concensus was you would get less than a 50% increase in yield. Yet again, it represent in the total lenght of the cycle a minor augmentation of time (28 hours days instead of 24 hours which translate as a 16.6% increase in flowering time, for some, as long as the increase in yield beats 16.6%, it is worth it.
There is some interesting information in this thread : https://www.icmag.com/ic/showthread.php?t=156499
Look for the posts by blckbrd, LJB and secondtry
secondtry did experiment with very long days (24 hours + if memory serves) and he would give one hours of light off during that time to give some rest to the plants.
Finally I remember reading about this guy who would go 12/12 but every 3 or 4 days he would leave his lights on for 24 hours instead of 12 (Basically reversing night and day) without the reveging or the plants going hermies. He was convinced it improved his yield.
I am confident there is a lots of knowledge to gain from experimenting with different photoperiods and that it is the next step to improve optimal yield conditions. I guess it also depends what matter most to you. Electricity usage, time till harvest, all the above, etc. I am sure people around ICMAG have exeperiment with this one way or the other. I'd be curious as well in there results.
I wonder with MOST timers being a 24 hour cycle how that would work.
I suppose you could find a timer that you could run those times, maybe multiple timers would work.
Well anyway I have been running
12on/5.5 off/1 on/ 5.5 off
Otherwise know as the gas lantern schedule.
I use to run a 18/6 for vegetative .
For the last 3-4 years I have been running this schedule without any hip cups.
I have insanely happy plants using the 12/1 and the energy savings comes with a big grin.
I use a couple of compact fluorescence for the 1 hour on time in the middle of their dark time to fool the plants to not release flowering auxin that keeps the plants in a vegetative state.
Since abandoning the 18/6 years ago I would not begin to think that is the best way to veg cannabis.
I am a big reader of my plants and they tell me This 12/1 is better by their big smiles and always looking like their standing on their tip toes just a reaching for the sky, like they cant quite grow fast enough.
Ratz
earthwyrms
Active member
thanks all, heres aome ideas, estimate of method
thanks all, heres aome ideas, estimate of method
if one timer on another, i have a hard time figuring it out so i'm scratching it down here as i go thinking. if a 18 connects to a twelve
#one
on |off
01 02 03 04 05 06 07 08 09 10 11 12 | 13 14 15 16 17 18 19 20 21 22 23 24
runs #2
on 1-18set/gets to 13 >cuts here, saves 13-18 for after #one 13-24
01 02 03 04 05 06 07 08 09 10 11 12 |13 14 15 16 17 18 | 19 20 21 22 23 24
on |off |^^^^^12hroff
13 14 15 16 17 18 | 19 20 21 22 23 24|
repeats
i realize this isn't quite it and it gets more complicated
#one
on |off
01 02 03 04 05 06 07 08 09 10 11 12 13 | 14 15 16 17 18 19 20 21 22 23 24
runs #2
on 13hrs 1-18set/gets to 14 >cuts here holds/off 11hrs
01 02 03 04 05 06 07 08 09 10 11 12 13 | 14 15 16 17 18 | 19 20 21 22 23 24
on 5hrs |off 6hrs |on 2h |#one off, holds/off 11hrs
14 15 16 17 18 | 19 20 21 22 23 24| 01 02|
on 13hrs |circuit down 11hrs
03 04 05 06 07 08 09 10 11 12 13 14 15 |
on 3hrs |off 6hrs |on 4hrs |circuit down 11hrs
16 17 18 | 19 20 21 22 23 24 | 01 02 03 04 |
on 13hrs |circuit down 11hrs
05 06 07 08 09 10 11 12 13 14 15 16 17 |
on1|off 6hrs |on 6hrs |circuit down 11 hrs
18 | 19 20 21 22 23 24 | 01 02 03 04 05 06 |
on 13hrs |off 5hrs |circuit down 11hrs
07 08 09 10 11 12 13 14 15 16 17 18 19 | 20 21 22 23 24 | (just realized this is the first part so this begins the next cycle)
1)13ON 11OFF
2)5ON 6OFF 2ON 11OFF
3)13ON 11OFF
4)03ON 06OFF 04ON 11OFF
5)13ON 11OFF
6)01ON 06OFF 06ON 11OFF
RECYCLES 13/11/05/06/02/11/13/11/03/06/04/11/13/11/01/06/06/11
i have more to look at
thanks all, heres aome ideas, estimate of method
if one timer on another, i have a hard time figuring it out so i'm scratching it down here as i go thinking. if a 18 connects to a twelve
#one
on |off
01 02 03 04 05 06 07 08 09 10 11 12 | 13 14 15 16 17 18 19 20 21 22 23 24
runs #2
on 1-18set/gets to 13 >cuts here, saves 13-18 for after #one 13-24
01 02 03 04 05 06 07 08 09 10 11 12 |13 14 15 16 17 18 | 19 20 21 22 23 24
on |off |^^^^^12hroff
13 14 15 16 17 18 | 19 20 21 22 23 24|
repeats
i realize this isn't quite it and it gets more complicated
#one
on |off
01 02 03 04 05 06 07 08 09 10 11 12 13 | 14 15 16 17 18 19 20 21 22 23 24
runs #2
on 13hrs 1-18set/gets to 14 >cuts here holds/off 11hrs
01 02 03 04 05 06 07 08 09 10 11 12 13 | 14 15 16 17 18 | 19 20 21 22 23 24
on 5hrs |off 6hrs |on 2h |#one off, holds/off 11hrs
14 15 16 17 18 | 19 20 21 22 23 24| 01 02|
on 13hrs |circuit down 11hrs
03 04 05 06 07 08 09 10 11 12 13 14 15 |
on 3hrs |off 6hrs |on 4hrs |circuit down 11hrs
16 17 18 | 19 20 21 22 23 24 | 01 02 03 04 |
on 13hrs |circuit down 11hrs
05 06 07 08 09 10 11 12 13 14 15 16 17 |
on1|off 6hrs |on 6hrs |circuit down 11 hrs
18 | 19 20 21 22 23 24 | 01 02 03 04 05 06 |
on 13hrs |off 5hrs |circuit down 11hrs
07 08 09 10 11 12 13 14 15 16 17 18 19 | 20 21 22 23 24 | (just realized this is the first part so this begins the next cycle)
1)13ON 11OFF
2)5ON 6OFF 2ON 11OFF
3)13ON 11OFF
4)03ON 06OFF 04ON 11OFF
5)13ON 11OFF
6)01ON 06OFF 06ON 11OFF
RECYCLES 13/11/05/06/02/11/13/11/03/06/04/11/13/11/01/06/06/11
i have more to look at
Experiments with other plant species such as thale cress and chrysanthemum indicate that most if not all plants perform best with 24 hour days. As stated above, the gain in yield caused by increased light exposure does not quite add up with the losses due later maturing or smaller growth. Simply exposing the plants to permanent light would be more efficient.
Those studies done with other species indicate that certain species seem to perform equally or nearly equally well under days with 48 or 72 h (= 2 or 3 times 24) but not with "odd" days.
Those studies done with other species indicate that certain species seem to perform equally or nearly equally well under days with 48 or 72 h (= 2 or 3 times 24) but not with "odd" days.
earthwyrms
Active member
post 25 by secondtry says "
"
https://www.icmag.com/ic/showthread.php?t=156499&page=2
i think someone here said their beans that didn't pop immediately, tended to pop around a certain moon phase, new moon i believe. i didn't find it on looking for it again
"
https://www.icmag.com/ic/showthread.php?t=156499&page=2
i think someone here said their beans that didn't pop immediately, tended to pop around a certain moon phase, new moon i believe. i didn't find it on looking for it again
earthwyrms
Active member
earthwyrms
Active member
consolidated some data, thanks
consolidated some data, thanks
ok, i realize it wasn't that.
the link the person posted on the water cress/Arabidopsis thaliana
http://www.jstor.org/stable/1514476?seq=1#page_scan_tab_contents
says in the abstract
>"Using this new system we demonstrated that, under continuous light, there was a longer circadian period for both stomatal conductance and CO2 fixation in the zietlupe (ztl-1) mutant compared to wild type."
>"Wild-type ZTL expression is therefore required for normal cycles of CO@ fixation and stomatal conductance. Furthermore, we demonstrate that different circadian periods can coexist in a single plant, highlighting the cell autonomous nature of the plant circadian oscillator"
what i looked through so far is also not about cannabis specifically.
http://link.springer.com/article/10.1007/BF00194433
about Phaseolus vulgaris L/common bean
"
Abstract
Persistent circadian rhythms in photosynthesis and stomatal opening occurred in bean (Phaseolus vulgaris L.) plants transferred from a natural photoperiod to a variety of constant conditions. Photosynthesis, measured as carbon assimilation, and stomatal opening, as conductance to water vapor, oscillated with a freerunning period close to 24 h under constant moderate light, as well as under light-limiting and CO2-limiting conditions. The rhythms damped under constant conditions conducive to high photosynthetic rates, as did rates of carbon assimilation and stomatal conductance, and this damping correlated with the accumulation of carbohydrate. No rhythm in respiration occurred in plants transferred to constant darkness, and the rhythm in stomatal opening damped rapidly in constant darkness. Damping of rhythms also occurred in leaflets exposed to constant light and CO2-free air, demonstrating that active photosynthesis and not simply light was necessary for sustained expression of these rhythms.
" "This is CIWDPB Publication No. 1142
This research was supported by National Science Foundation grant BSR 8717422 (C.B.F.) and a U.S. Department of Agriculture training grant to Stanford University (T.L.H.)." "Article
Planta
March 1993, Volume 189, Issue 3, pp 369-376" <<< and still costs money, "
$39.95 / €34.95 / £29.95 *
"
^^^^it says "The rhythms damped under constant conditions conducive to high photosynthetic rates, as did rates of carbon assimilation and stomatal conductance, and this damping correlated with the accumulation of carbohydrate"
and when they removed the CO2 from otherwise good conditions, the damping of cycles occured. it doesn't say what damping is.
http://www.plantphysiol.org/content/96/3/831.abstract
about Phaseolus vulgaris L/common bean (says here red kidney bean)
"
Abstract
Net carbon assimilation and stomatal conductance to water vapor oscillated repeatedly in red kidney bean, Phaseolus vulgaris L., plants transferred from a natural photoperiod to constant light. In a gas exchange system with automatic regulation of selected environmental and physiological variables, assimilation and conductance oscillated with a free-running period of approximately 24.5 hours. The rhythms in carbon assimilation and stomatal conductance were closely coupled and persisted for more than a week under constant conditions. A rhythm in assimilation occurred when either ambient or intercellular CO2 partial pressure was held constant, demonstrating that the rhythm in assimilation was not entirely the result of stomatal effects on CO2 diffusion. Rhythms in assimilation and conductance were not expressed in plants grown under constant light at a constant temperature, demonstrating that the rhythms did not occur spontaneously but were induced by an external stimulus. In plants grown under constant light with a temperature cycle, a rhythm was entrained in stomatal conductance but not in carbon assimilation, indicating that the oscillators driving the rhythms differed in their sensitivity to environmental stimuli.
" <<<this one is free for view/download on the pdf
these parts
>>"The rhythms damped under constant conditions conducive to high photosynthetic rates, as did rates of carbon assimilation and stomatal conductance, and this damping correlated with the accumulation of carbohydrate."
>>"Rhythms in assimilation and conductance were not expressed in plants grown under constant light at a constant temperature, demonstrating that the rhythms did not occur spontaneously but were induced by an external stimulus."
>>>>>"In plants grown under constant light with a temperature cycle, a rhythm was entrained in stomatal conductance but not in carbon assimilation, indicating that the oscillators driving the rhythms differed in their sensitivity to environmental stimuli."
it seems the temperature changes did something
the poster also listed this one http://www.plantphysiol.org/content/102/3/859.full.pdf which is extensive and i did not read yet.
i stumbled on to this page http://www.mrnice.nl/forum/6-breeders-support-information/5340-c3-c4-photosynthesis.html
when i was stumbled on Carbon fixation types from the link of the poster http://web.archive.org/web/20030306020209/http://www.geocities.com/CapeCanaveral/Hall/2385/rate.htm
where it says "Oxygen
Oxygen competes with carbon dioxide for the active site of RuBP carboxylase, the carbon dioxide fixing enzyme. This means that relatively high concentrations of oxygen, for example the 21% in our atmosphere, inhibit photosynthesis. Oxygen does not inhibit carbon dioxide fixation in the C4 plants. "
it doesn't have any sources besides "Created by Nicola Kerrison" and i don't know where it is from and i searched to see if cannabis is C4 and saw that page after being confused because i saw some places it was said to be C3, no where that seemed to be a good source. and when i skimmed "C3 carbon fixation" on wikipedia
https://en.wikipedia.org/wiki/C3_carbon_fixation
i read "C3 plants cannot grow in hot areas because RuBisCO incorporates more oxygen into RuBP as temperatures increase. This leads to photorespiration, which leads to a net loss of carbon and nitrogen from the plant and can, therefore, limit growth. In dry areas, C3 plants shut their stomata to reduce water loss, but this stops CO2 from entering the leaves and, therefore, reduces the concentration of CO2 in the leaves. This lowers the CO2:O2 ratio and, therefore, also increases photorespiration. C4 and CAM plants have adaptations that allow them to survive in hot and dry areas, and they can, therefore, out-compete C3 plants."
and i thought it didn't make sense if cannabis is in the hot tropical regions
so i haven't read through http://www.mrnice.nl/forum/6-breeders-support-information/5340-c3-c4-photosynthesis.html yet and hope to
the posters R043 pointed me towards,
secondtry
"
"
"
"
"
"
then the quote from last last post
"
"
the infrared light thing may do something as that was 2010 and now there are 730nm in full spectrum LEDs
Blckbrd wrote
"
"
"
"
"
"
ShroomDr had posted right before Blckbrd
"
"
and last and not least, actually first breakthrough on the thread posted by LJB
"
"
i hope that helps getting it concentrated
thanks
consolidated some data, thanks
ok, i realize it wasn't that.
the link the person posted on the water cress/Arabidopsis thaliana
http://www.jstor.org/stable/1514476?seq=1#page_scan_tab_contents
says in the abstract
>"Using this new system we demonstrated that, under continuous light, there was a longer circadian period for both stomatal conductance and CO2 fixation in the zietlupe (ztl-1) mutant compared to wild type."
>"Wild-type ZTL expression is therefore required for normal cycles of CO@ fixation and stomatal conductance. Furthermore, we demonstrate that different circadian periods can coexist in a single plant, highlighting the cell autonomous nature of the plant circadian oscillator"
what i looked through so far is also not about cannabis specifically.
http://link.springer.com/article/10.1007/BF00194433
about Phaseolus vulgaris L/common bean
"
Abstract
Persistent circadian rhythms in photosynthesis and stomatal opening occurred in bean (Phaseolus vulgaris L.) plants transferred from a natural photoperiod to a variety of constant conditions. Photosynthesis, measured as carbon assimilation, and stomatal opening, as conductance to water vapor, oscillated with a freerunning period close to 24 h under constant moderate light, as well as under light-limiting and CO2-limiting conditions. The rhythms damped under constant conditions conducive to high photosynthetic rates, as did rates of carbon assimilation and stomatal conductance, and this damping correlated with the accumulation of carbohydrate. No rhythm in respiration occurred in plants transferred to constant darkness, and the rhythm in stomatal opening damped rapidly in constant darkness. Damping of rhythms also occurred in leaflets exposed to constant light and CO2-free air, demonstrating that active photosynthesis and not simply light was necessary for sustained expression of these rhythms.
" "This is CIWDPB Publication No. 1142
This research was supported by National Science Foundation grant BSR 8717422 (C.B.F.) and a U.S. Department of Agriculture training grant to Stanford University (T.L.H.)." "Article
Planta
March 1993, Volume 189, Issue 3, pp 369-376" <<< and still costs money, "
$39.95 / €34.95 / £29.95 *
"
^^^^it says "The rhythms damped under constant conditions conducive to high photosynthetic rates, as did rates of carbon assimilation and stomatal conductance, and this damping correlated with the accumulation of carbohydrate"
and when they removed the CO2 from otherwise good conditions, the damping of cycles occured. it doesn't say what damping is.
http://www.plantphysiol.org/content/96/3/831.abstract
about Phaseolus vulgaris L/common bean (says here red kidney bean)
"
Abstract
Net carbon assimilation and stomatal conductance to water vapor oscillated repeatedly in red kidney bean, Phaseolus vulgaris L., plants transferred from a natural photoperiod to constant light. In a gas exchange system with automatic regulation of selected environmental and physiological variables, assimilation and conductance oscillated with a free-running period of approximately 24.5 hours. The rhythms in carbon assimilation and stomatal conductance were closely coupled and persisted for more than a week under constant conditions. A rhythm in assimilation occurred when either ambient or intercellular CO2 partial pressure was held constant, demonstrating that the rhythm in assimilation was not entirely the result of stomatal effects on CO2 diffusion. Rhythms in assimilation and conductance were not expressed in plants grown under constant light at a constant temperature, demonstrating that the rhythms did not occur spontaneously but were induced by an external stimulus. In plants grown under constant light with a temperature cycle, a rhythm was entrained in stomatal conductance but not in carbon assimilation, indicating that the oscillators driving the rhythms differed in their sensitivity to environmental stimuli.
" <<<this one is free for view/download on the pdf
these parts
>>"The rhythms damped under constant conditions conducive to high photosynthetic rates, as did rates of carbon assimilation and stomatal conductance, and this damping correlated with the accumulation of carbohydrate."
>>"Rhythms in assimilation and conductance were not expressed in plants grown under constant light at a constant temperature, demonstrating that the rhythms did not occur spontaneously but were induced by an external stimulus."
>>>>>"In plants grown under constant light with a temperature cycle, a rhythm was entrained in stomatal conductance but not in carbon assimilation, indicating that the oscillators driving the rhythms differed in their sensitivity to environmental stimuli."
it seems the temperature changes did something
the poster also listed this one http://www.plantphysiol.org/content/102/3/859.full.pdf which is extensive and i did not read yet.
i stumbled on to this page http://www.mrnice.nl/forum/6-breeders-support-information/5340-c3-c4-photosynthesis.html
when i was stumbled on Carbon fixation types from the link of the poster http://web.archive.org/web/20030306020209/http://www.geocities.com/CapeCanaveral/Hall/2385/rate.htm
where it says "Oxygen
Oxygen competes with carbon dioxide for the active site of RuBP carboxylase, the carbon dioxide fixing enzyme. This means that relatively high concentrations of oxygen, for example the 21% in our atmosphere, inhibit photosynthesis. Oxygen does not inhibit carbon dioxide fixation in the C4 plants. "
it doesn't have any sources besides "Created by Nicola Kerrison" and i don't know where it is from and i searched to see if cannabis is C4 and saw that page after being confused because i saw some places it was said to be C3, no where that seemed to be a good source. and when i skimmed "C3 carbon fixation" on wikipedia
https://en.wikipedia.org/wiki/C3_carbon_fixation
i read "C3 plants cannot grow in hot areas because RuBisCO incorporates more oxygen into RuBP as temperatures increase. This leads to photorespiration, which leads to a net loss of carbon and nitrogen from the plant and can, therefore, limit growth. In dry areas, C3 plants shut their stomata to reduce water loss, but this stops CO2 from entering the leaves and, therefore, reduces the concentration of CO2 in the leaves. This lowers the CO2:O2 ratio and, therefore, also increases photorespiration. C4 and CAM plants have adaptations that allow them to survive in hot and dry areas, and they can, therefore, out-compete C3 plants."
and i thought it didn't make sense if cannabis is in the hot tropical regions
so i haven't read through http://www.mrnice.nl/forum/6-breeders-support-information/5340-c3-c4-photosynthesis.html yet and hope to
the posters R043 pointed me towards,
secondtry
"
"
"
"
"
"
then the quote from last last post
"
"
the infrared light thing may do something as that was 2010 and now there are 730nm in full spectrum LEDs
Blckbrd wrote
"
"
"
"
"
"
ShroomDr had posted right before Blckbrd
"
"
and last and not least, actually first breakthrough on the thread posted by LJB
"
"
i hope that helps getting it concentrated
thanks
OP you did a hell of a job reporting all this.
I hope you found some of this information useful.
I believe the only way for sure will be to test for yourself.
I remember reading that Blckbrd believe there is no loss in yield. However I also remember reading everything I could find on the subject on different forums and most of the people who tried a shorter day than 12 hours had report a small loss in yield.
It wasn't clearly stated like I am about to do in all those post I have read but it is my belief that the confusion as to weither the yield suffer or not might arise from the point of view you adopt. As stated in my previous post, if you manage to save 20% on the total flowering cycle time, a yield of 80% should be considered the break even point. Maybe some of the posters took that in consideration and maybe others didn't.
As for the Far Red at the begging of the dark period, I have found no one that tried it with any sort of succes. It kind of saddens me as a shorter night period combined with a shorter day period would shorten even more the cycle with obvious gain in optimising the yield. Yet the theory was based on the hourglass model which has been demonstrated to be at least incomplete and at worst, plain false.
Yet given the chance, I would love to sidetest all those cycle manipulation (including the Far Red thing). I am still convinced as already stated that there is still a lot to be tested and room for improvment with cycle manipulation. Breeding for shorter critical period might also be an avenue worth exploring in maximising yield.
I hope you found some of this information useful.
I believe the only way for sure will be to test for yourself.
I remember reading that Blckbrd believe there is no loss in yield. However I also remember reading everything I could find on the subject on different forums and most of the people who tried a shorter day than 12 hours had report a small loss in yield.
It wasn't clearly stated like I am about to do in all those post I have read but it is my belief that the confusion as to weither the yield suffer or not might arise from the point of view you adopt. As stated in my previous post, if you manage to save 20% on the total flowering cycle time, a yield of 80% should be considered the break even point. Maybe some of the posters took that in consideration and maybe others didn't.
As for the Far Red at the begging of the dark period, I have found no one that tried it with any sort of succes. It kind of saddens me as a shorter night period combined with a shorter day period would shorten even more the cycle with obvious gain in optimising the yield. Yet the theory was based on the hourglass model which has been demonstrated to be at least incomplete and at worst, plain false.
Yet given the chance, I would love to sidetest all those cycle manipulation (including the Far Red thing). I am still convinced as already stated that there is still a lot to be tested and room for improvment with cycle manipulation. Breeding for shorter critical period might also be an avenue worth exploring in maximising yield.
Finally managed to get my hands on an Exo-Terra Night Light... if the spectrum chart is correct (would be the first one I've seen from that company), then this bulb might be suitable for a far red experiment. Wondering if the additional heat does act contradictory, though. Best would be a far red LED to try but it's just a fun thing for me.
From my point of view, the use of far red light might allow a grower to have longer days than usual which still induce flowering. Thereby, one certainly doesn't safe energy but might gain in yield. If the extra effort pays off, I don't know and I don't care cause I grow under meagre ~200 W
. This is also a point to consider: If growing at high and long irradiation, the plant 'saturates' at some point and hence, more won't do more. On the other hand, at low irradiation, every minute of daytime you add should bring a benefit yield-wise (but not necessarily g/W).I honestly don't see a benefit for far red light (didn't pay it much thoughts, though) in 'unnatural' day/night schedules.
It would be an interesting experiment for sure.
Do you already know the critical period of your strain ?
At that low irradiance, you might even benefit of increasing the day time even if you stick to 12 hours of darkness. Might be worthy of your time to test this as well.
If the graph I found online is the one of your lamp and if, as you said, it is accurate, it seems to me that some light would be absorbed by Pr phytochrome as well.
I would not be confident that the fact that most of it's bandwidth is over 700 nm is enough to compensate the Pr that will be reconvert into Pfr but actually I just have no idea. I just wanted to point it out as it is something you might want to take into consideration before experimenting. Namely, that even if it doesnt work with your set up, it might not disproof the theory and because of this maybe it is not worth your time to experiment with.
If you are really into this you could try with some 730 nm LED.
The benefit would be the same as with a 12/12 schedule. By reducing the night time lenght you either accelerate the time until harvest (say you go 12/10 or even 10/10 or if your strain has already a short critical you might go 10/8) or you go with longer day time (18/8 or 16/10) which gives the plant more light and hopefully more yield.
Do you already know the critical period of your strain ?
At that low irradiance, you might even benefit of increasing the day time even if you stick to 12 hours of darkness. Might be worthy of your time to test this as well.
If the graph I found online is the one of your lamp and if, as you said, it is accurate, it seems to me that some light would be absorbed by Pr phytochrome as well.
I would not be confident that the fact that most of it's bandwidth is over 700 nm is enough to compensate the Pr that will be reconvert into Pfr but actually I just have no idea. I just wanted to point it out as it is something you might want to take into consideration before experimenting. Namely, that even if it doesnt work with your set up, it might not disproof the theory and because of this maybe it is not worth your time to experiment with.
If you are really into this you could try with some 730 nm LED.
The benefit would be the same as with a 12/12 schedule. By reducing the night time lenght you either accelerate the time until harvest (say you go 12/10 or even 10/10 or if your strain has already a short critical you might go 10/8) or you go with longer day time (18/8 or 16/10) which gives the plant more light and hopefully more yield.
My strain? *Chuckle* I do have several different varieties in seed form which I never tried, several land race I never grew, and hemp, a lot of it. I'm not really into growing the same stuff over and over again . The nice thing with hemp is that it has approximately 14 h of minimal night length though their origin does affect the way they react to temperature and "accumulated irradiation" (what was the official abbreviation again). Anyway, the 14 hours are quite reliable under lower light intensity and also what I observed with several other varieties.
True, if it doesn't work I'll know as much as before. It might also be that I didn't got the right window (time or duration of illumination with far red light)... But most likely, that bulb just puts out too much visible light to be of any use other than heating up the room, I'm well aware of that. Yes, the LED would be THE first and best choice but my interest does only go so far as to get the bulb out of the shelf when buying other stuff nearby .
. The nice thing with hemp is that it has approximately 14 h of minimal night length though their origin does affect the way they react to temperature and "accumulated irradiation" (what was the official abbreviation again). Anyway, the 14 hours are quite reliable under lower light intensity and also what I observed with several other varieties.True, if it doesn't work I'll know as much as before. It might also be that I didn't got the right window (time or duration of illumination with far red light)... But most likely, that bulb just puts out too much visible light to be of any use other than heating up the room, I'm well aware of that. Yes, the LED would be THE first and best choice but my interest does only go so far as to get the bulb out of the shelf when buying other stuff nearby
.I completly understand. In any case I would still be curious in the outcome of your experiment so there is no reasons why you shouldn't be either.
DLI was the acronyme you were looking for. Daily Light Integral.
I didn't really assumed you would grow only one strain, it just came out like that. If you grow something with 14 hours of critical then there is definetly a good reason to try and reduce this. I am still wondering why you think it is a nice thing.
Maybe by now you have figured I am quite curious, which is why I need to ask. When you refer to hemp, do you mean you are growing the non psychoactive hemp as opposed to cannabis ? Nothing wrong with that. Just a bit surprising. I am asking because I wanted to make this is what you meant and not some kind of exotic old school cannabis strain.
Should it be that I misunderstood and that it was indeed some psychoactive variety you refer to as hemp, then I would be quite curious about in what ways do they react to temperature and DLI.
DLI was the acronyme you were looking for. Daily Light Integral.
I didn't really assumed you would grow only one strain, it just came out like that. If you grow something with 14 hours of critical then there is definetly a good reason to try and reduce this. I am still wondering why you think it is a nice thing.
Maybe by now you have figured I am quite curious, which is why I need to ask. When you refer to hemp, do you mean you are growing the non psychoactive hemp as opposed to cannabis ? Nothing wrong with that. Just a bit surprising. I am asking because I wanted to make this is what you meant and not some kind of exotic old school cannabis strain.
Should it be that I misunderstood and that it was indeed some psychoactive variety you refer to as hemp, then I would be quite curious about in what ways do they react to temperature and DLI.
That whole far red light thing is simply fascinating. It also might tell me the natural delay or Pr to turn into Pfr or in other words the 'real' minimal night length and not the apparent one (e.g. something between 10 and 13 hours based on other plant species). Lets assume that the use of far red would turn the minimal night length for flower induction down to 10, then I could use my meagre wattage 14 instead of 10 hours per day and still keep the natural (allegedly best) day length interval. This is a considerable increase in photosynthesis and hence product quality combined with less stretch and blablabla .
Some of my hemp varieties, yes fibre/seed hemp aka industrial hemp, contain psychoactive individuals. Check out my gallery and follow the link in my signature for more infos.
.Some of my hemp varieties, yes fibre/seed hemp aka industrial hemp, contain psychoactive individuals. Check out my gallery and follow the link in my signature for more infos.
Yes it is a very interesting topic. There are obvious advantage if it works, that is for sure.
You mentionned some and I others, there are probably more we haven't think of yet.
A long day plant could be kept in veg while receving longer light time and faster grow.
Lots of cool possibilities.
I've said earlier in this thread that I haven't found anyone who claimed to have try this with success. While going through my archives, I've found a link I forgot. I have no idea what degree of credibility to give the guy but actually I was wrong. He does claim to have use this with success.
http://www.growweedeasy.com/phytochrome-manipulation-cannabis
I am not sure what you mean by the "apparent one". Maybe you meant you go with a standard 14 hours of darkness (which would be the apparent one) and mean you never tried to find the exact minimum critical (that would of course vary from strain to strain).
In any case, I've heard the best way to find the exact critical period would be to start, when ready to flip, with 9 hours of darkness. Each week you add 15 minutes of darkness. Once you see flowers, you know the critical is somewhere close to your current night lengt minus 15 - 30 minutes (1 to 2 weeks prior to this point the plant started flowering). Next run you can pinpoint this precisely.
As for psychoactive hemp you got me extremely interested and I am on my way to the link in your sig. Right now.
You mentionned some and I others, there are probably more we haven't think of yet.
A long day plant could be kept in veg while receving longer light time and faster grow.
Lots of cool possibilities.
I've said earlier in this thread that I haven't found anyone who claimed to have try this with success. While going through my archives, I've found a link I forgot. I have no idea what degree of credibility to give the guy but actually I was wrong. He does claim to have use this with success.
http://www.growweedeasy.com/phytochrome-manipulation-cannabis
I am not sure what you mean by the "apparent one". Maybe you meant you go with a standard 14 hours of darkness (which would be the apparent one) and mean you never tried to find the exact minimum critical (that would of course vary from strain to strain).
In any case, I've heard the best way to find the exact critical period would be to start, when ready to flip, with 9 hours of darkness. Each week you add 15 minutes of darkness. Once you see flowers, you know the critical is somewhere close to your current night lengt minus 15 - 30 minutes (1 to 2 weeks prior to this point the plant started flowering). Next run you can pinpoint this precisely.
As for psychoactive hemp you got me extremely interested and I am on my way to the link in your sig. Right now.
Oh and I am not sure if it is a typo but for the people who will read this and get confused, it is actually the Pfr that revert to Pr in the absence of light. Not the other way around. That is the reason you want to flash Far Red light, so Pfr phytochrome revert faster than they do naturally.
One last thing, if this was the only mechanism at work for the plant to know the night time lenght, one could flash Far Red for an hour only and then start another day cycle. Of course this won't work and we know that this model (called the hourglass model) is incomplete. Still, shortning the night lenght by one or more hours would be great.
One last thing, if this was the only mechanism at work for the plant to know the night time lenght, one could flash Far Red for an hour only and then start another day cycle. Of course this won't work and we know that this model (called the hourglass model) is incomplete. Still, shortning the night lenght by one or more hours would be great.
earthwyrms
Active member
R043 i found it odd on http://www.growweedeasy.com/phytochrome-manipulation-cannabis that the writer wrote
"Long day and short day plants react just the opposite to phytochrome manipulation. Where as high red, low far red light stimulates flowering in long day plants, it's just the opposite in short day plants like cannabis."
does the writer mean High Far Red and Low Red is beneficiary for flowering cannabis?
i'm not sure what to make about the rest of his paragraph on that with wattage being unmentioned
i watched this video, https://www.youtube.com/watch?v=xMCupB8pSZ8, which is 1:39 minutes, which gave me a start on understanding phytochromes, although i got confused at the end. Pr absorbs red, Pfr absorbs far red. they can interconvert somehow. red helps Pr turn to Pfr. Pfr can be bound to a protien and work on DNA (im guessing it doesn't back convert after this or is used up?)
perhaps if the main lights are turned off or dimmed for an hour and the temperature is either kept constant from a heat lamp also use the far red LEDs and/or infrared LEDs, there could be a reset or hourglass effect.
maybe not
concerning the night time anyway, there's a black (totally black opaque glass) ceramic heat bulb by fuxin that is black and made tobarely light and glow like the moon i believe it was written.
the bulbs are in wattages from 25W to 100W and the flat faced type with the spiral pattern is supposed them to be better for efficiency
they are "E27 ceramic heat bulb" or something like that [beware of mains types, 110v or 220v] it gives off Far Infrared
Black Dog LED has a paper about leaf temperature.
https://www.blackdogled.com/lst
"There is a prevailing consensus that 75 °F is the ideal ambient temperature to grow Cannabis under HPS lighting without CO2 supplementation. This experimental result indicates that an 84 °F ambient air temperature is required to achieve the same optimal leaf surface temperatures when using plant-optimized LED lighting-- and that a 75 °F ambient air temperature with LED lighting would not achieve optimal leaf surface temperatures, slowing metabolic rates and leaf and flower production."
maybe some combination of the fuxin far infrared lamp, the 730nm far red LEDs and/or the 940nm invisible infrared LEDs can have a good effect on plants if turned on as the lights are turned off or before they come on for some amount of time.
the 940nm LEDs are supposedly true invisible infrared which maybe doesn't do anything beneficial although i don't know if i saw any tests otherwise.
i am wondering about the 1000nm to 1500+nm fiber optic/telecommunication wavelengths and what they might do too.
i was wondering if UV flashes or pulses at night instead day of 280nm might do something good. maybe randomly or patterns or super low amounts continually. there are led diodes from 275nm +-5nm at mW levels, which maybe can be run continually, even at night to make a possible simulated background for the plant to produce THC to counter.
I read 280-310nm stimulates THC production
about the lower light intensity
you both may be interested in post #344 here
https://www.icmag.com/ic/showthread.php?t=108973&page=23
and lastly, what if 650nm lasers only half a watt can be focused to cover plant leaves, not as a dot, but through a collimated image projector or just a unfocused lens. there are lots of 100 diodes encased in heatsinks at 5mW power (consumption or radiant, i don't know) for around $23 i think.
thats got to be a good experiment, plant with light as control, same plant with same light and those lasers shining diffuse on the leaves as the experiment, in amounts untill a difference is noticed.
i think 650nm is close to one of the peak absorbtions, not peak but close to 630nm and i t don't remember the other one in the 600s.
"Long day and short day plants react just the opposite to phytochrome manipulation. Where as high red, low far red light stimulates flowering in long day plants, it's just the opposite in short day plants like cannabis."
does the writer mean High Far Red and Low Red is beneficiary for flowering cannabis?
i'm not sure what to make about the rest of his paragraph on that with wattage being unmentioned
i watched this video, https://www.youtube.com/watch?v=xMCupB8pSZ8, which is 1:39 minutes, which gave me a start on understanding phytochromes, although i got confused at the end. Pr absorbs red, Pfr absorbs far red. they can interconvert somehow. red helps Pr turn to Pfr. Pfr can be bound to a protien and work on DNA (im guessing it doesn't back convert after this or is used up?)
perhaps if the main lights are turned off or dimmed for an hour and the temperature is either kept constant from a heat lamp also use the far red LEDs and/or infrared LEDs, there could be a reset or hourglass effect.
maybe not
concerning the night time anyway, there's a black (totally black opaque glass) ceramic heat bulb by fuxin that is black and made tobarely light and glow like the moon i believe it was written.
the bulbs are in wattages from 25W to 100W and the flat faced type with the spiral pattern is supposed them to be better for efficiency
they are "E27 ceramic heat bulb" or something like that [beware of mains types, 110v or 220v] it gives off Far Infrared
Black Dog LED has a paper about leaf temperature.
https://www.blackdogled.com/lst
"There is a prevailing consensus that 75 °F is the ideal ambient temperature to grow Cannabis under HPS lighting without CO2 supplementation. This experimental result indicates that an 84 °F ambient air temperature is required to achieve the same optimal leaf surface temperatures when using plant-optimized LED lighting-- and that a 75 °F ambient air temperature with LED lighting would not achieve optimal leaf surface temperatures, slowing metabolic rates and leaf and flower production."
maybe some combination of the fuxin far infrared lamp, the 730nm far red LEDs and/or the 940nm invisible infrared LEDs can have a good effect on plants if turned on as the lights are turned off or before they come on for some amount of time.
the 940nm LEDs are supposedly true invisible infrared which maybe doesn't do anything beneficial although i don't know if i saw any tests otherwise.
i am wondering about the 1000nm to 1500+nm fiber optic/telecommunication wavelengths and what they might do too.
i was wondering if UV flashes or pulses at night instead day of 280nm might do something good. maybe randomly or patterns or super low amounts continually. there are led diodes from 275nm +-5nm at mW levels, which maybe can be run continually, even at night to make a possible simulated background for the plant to produce THC to counter.
I read 280-310nm stimulates THC production
about the lower light intensity
you both may be interested in post #344 here
https://www.icmag.com/ic/showthread.php?t=108973&page=23
and lastly, what if 650nm lasers only half a watt can be focused to cover plant leaves, not as a dot, but through a collimated image projector or just a unfocused lens. there are lots of 100 diodes encased in heatsinks at 5mW power (consumption or radiant, i don't know) for around $23 i think.
thats got to be a good experiment, plant with light as control, same plant with same light and those lasers shining diffuse on the leaves as the experiment, in amounts untill a difference is noticed.
i think 650nm is close to one of the peak absorbtions, not peak but close to 630nm and i t don't remember the other one in the 600s.
Lets see if I can clarify things for you. Since I am not aware of what you already know, forgive me if I go in too much details on things you already have a good grasp on. At least it might be of interest for people who read this and haven't been exposed yet to those concept.
First remember all of this is theoretical and the link I provided and that you quoted is the only one I found on the net where someone claim to have success using it on Cannabis.
"Long day and short day plants react just the opposite to phytochrome manipulation"
Cannabis is a short day plant. As you know, if you keep the daylight long enough, it will stay in vegetative. If you want your plant to start flowering, you will reduce the daylight length. Wich is why it is called a short day plant.
Long day plants are exactly the opposite. They will stay in vegetative as long as the day are under a certain daylight lenght. To induce flowering, you will need to expose them to longer daylight.
You would think that plant woud somehow know the duration of daylight lenght, but actually it is the duration of the night that the plant is aware of (in a manner of speaking). So calling them long day or short day is kind of a misnommer and calling them short night or long night plants would make more sens.
Back to the quotation, we have clarify short day and long day plants. Now "phytochrome manipulation" in this context refer to using the knowledge about Pr and Pfr to have an effect on inducing or preventing flowering.
Outside the scope of this article, phytochrome manipulation could mean something else. For exemple, elongation is known to be tied to the Pr/Pfr ratio whithin the plant during day time.
Before going on with the next part of the quote let's specify something.
The minimal night lenght necessary to induce flowering in short day plant is called the critical period. In long day plant, the critical period is the maximum night length that induce flowering. It should be noted that different strains and most likely different pheno will have different critical period. 12/12 have been adopted and widely used because it is short enough to induce flowering in most strain. Yet, there are report of strains (mostly some Sativas and Sativa dominant hybrid) responding better with longer night than 12 hours.
Earlier in this thread I mentionned the theory that at the beggining of night time, flashing Cannabis with Far Red could theoretically reduce the night critical period. The article we are quoting state a slightly different approach.
Basically, he says there are strains that will flower under 14/10 (so the critical would theoretically be 10 hours). Yet he also says that from his experience, a strain flowered under 14/10 will take longer to finish it's flowering cycle than ir it was under 12/12. Instead of flashing his Far Red at the beggining of the night, he adds it to his spectrum at the end of the day cycle, making sure also to lower his Red spectrum.
"Where as high red, low far red light stimulates flowering in long day plants, it's just the opposite in short day plants like cannabis"
No, he is just saying that you need at the end of the day cycle a high Far Red and low Red spectrum to help induce flowering and to avoid slowing the full flowering cycle all the while using 14/10 (which he states increase total yield).
Note that it does not mean that it would be benificial to keep this spectrum day long through flowering. Or that it would be beneficial under 12/12 (yet it could be with some strains that respond better with 11/13).
I am not sure what exactly you refer to. But you do not need wattage to make sens of all this. The spectrum is the intensity of light at different wavelenght. So supplementing Far Red shouldn't be too hard. But making sure to have a low Red would need some creativity for sure. If I was growing under HID and really wanted to try this, I would add some LED whitout the Red band and turn off the HID for the last hour.
This is 100% correct.
Not somehow. When Pr absorb Red, it turns into Pfr. When Pfr absorb Far Red, it reverts to Pr.
What is interesting is that even in the absence of Far Red (so at night) Pfr slowly revert to Pr. This would be one of the different mechanism by which plants are aware of the night lenght. The longer the night, the less Pfr left.
I was exposed to this for the first while watching the video from your link. It was only state as an exemple of the different role Phytochromes plays. The video stated it was the case of certain plants only. I do not know if Cannabis is one of them but it is irrelevant to this discussion.
I really did not understand exactly where you were getting at with the rest of your post. However you talked about very high nm which are purely infrared and not Far Red. Pfr will aborb less past 730 nm and I would think not much above 800 nm (yet I might be wrong).
I have joined the graph of Phytochrome absorbtion spectrum so you can see visually want I am talking about. It is interesting to see they absorb also in the blue wavelenght and even in UV. For this reason, I would avoid pulsing UVB at night. Alhto I might be wrong and it might work, I see not benefit in trying this since UVB addition in day time works.
Well I hope this was useful.
First remember all of this is theoretical and the link I provided and that you quoted is the only one I found on the net where someone claim to have success using it on Cannabis.
"Long day and short day plants react just the opposite to phytochrome manipulation"
Cannabis is a short day plant. As you know, if you keep the daylight long enough, it will stay in vegetative. If you want your plant to start flowering, you will reduce the daylight length. Wich is why it is called a short day plant.
Long day plants are exactly the opposite. They will stay in vegetative as long as the day are under a certain daylight lenght. To induce flowering, you will need to expose them to longer daylight.
You would think that plant woud somehow know the duration of daylight lenght, but actually it is the duration of the night that the plant is aware of (in a manner of speaking). So calling them long day or short day is kind of a misnommer and calling them short night or long night plants would make more sens.
Back to the quotation, we have clarify short day and long day plants. Now "phytochrome manipulation" in this context refer to using the knowledge about Pr and Pfr to have an effect on inducing or preventing flowering.
Outside the scope of this article, phytochrome manipulation could mean something else. For exemple, elongation is known to be tied to the Pr/Pfr ratio whithin the plant during day time.
Before going on with the next part of the quote let's specify something.
The minimal night lenght necessary to induce flowering in short day plant is called the critical period. In long day plant, the critical period is the maximum night length that induce flowering. It should be noted that different strains and most likely different pheno will have different critical period. 12/12 have been adopted and widely used because it is short enough to induce flowering in most strain. Yet, there are report of strains (mostly some Sativas and Sativa dominant hybrid) responding better with longer night than 12 hours.
Earlier in this thread I mentionned the theory that at the beggining of night time, flashing Cannabis with Far Red could theoretically reduce the night critical period. The article we are quoting state a slightly different approach.
Basically, he says there are strains that will flower under 14/10 (so the critical would theoretically be 10 hours). Yet he also says that from his experience, a strain flowered under 14/10 will take longer to finish it's flowering cycle than ir it was under 12/12. Instead of flashing his Far Red at the beggining of the night, he adds it to his spectrum at the end of the day cycle, making sure also to lower his Red spectrum.
"Where as high red, low far red light stimulates flowering in long day plants, it's just the opposite in short day plants like cannabis"
No, he is just saying that you need at the end of the day cycle a high Far Red and low Red spectrum to help induce flowering and to avoid slowing the full flowering cycle all the while using 14/10 (which he states increase total yield).
Note that it does not mean that it would be benificial to keep this spectrum day long through flowering. Or that it would be beneficial under 12/12 (yet it could be with some strains that respond better with 11/13).
I am not sure what exactly you refer to. But you do not need wattage to make sens of all this. The spectrum is the intensity of light at different wavelenght. So supplementing Far Red shouldn't be too hard. But making sure to have a low Red would need some creativity for sure. If I was growing under HID and really wanted to try this, I would add some LED whitout the Red band and turn off the HID for the last hour.
This is 100% correct.
Not somehow. When Pr absorb Red, it turns into Pfr. When Pfr absorb Far Red, it reverts to Pr.
What is interesting is that even in the absence of Far Red (so at night) Pfr slowly revert to Pr. This would be one of the different mechanism by which plants are aware of the night lenght. The longer the night, the less Pfr left.
I was exposed to this for the first while watching the video from your link. It was only state as an exemple of the different role Phytochromes plays. The video stated it was the case of certain plants only. I do not know if Cannabis is one of them but it is irrelevant to this discussion.
I really did not understand exactly where you were getting at with the rest of your post. However you talked about very high nm which are purely infrared and not Far Red. Pfr will aborb less past 730 nm and I would think not much above 800 nm (yet I might be wrong).
I have joined the graph of Phytochrome absorbtion spectrum so you can see visually want I am talking about. It is interesting to see they absorb also in the blue wavelenght and even in UV. For this reason, I would avoid pulsing UVB at night. Alhto I might be wrong and it might work, I see not benefit in trying this since UVB addition in day time works.
Well I hope this was useful.
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