# increased yeild with photoperiod



## moash (Sep 26, 2009)

i found this while browsing around
has anyone ever tried this???



The only photoperiod manipulation from years of experiments that offered discernible improvements was the following photoperiod adjustment made for 1 or 2 calendar weeks at the point of maximum flowering rate: Daylength of 21 hours, 36 minutes with a dark period of 12 hours. To accomplish this, you need a 7 day, 24 hour digital timer. During a 7 day calendar week on Earth, the "sun" only cycles 5 times. This permits easily switching back to the regular 12/12 at your discretion. You may want to only alter during peak flower production to stimulate the plant's metabolism. Using this photoperiod throughout the flowering cycle will cause this: 

A variety that takes 49 days of 12/12 to mature, won't see 49 - 12 hour dark periods under 21:36/12 until almost 10 calendar weeks have passed. 

The total increase in light energy is almost 80%, which will produce larger yields, if all of your other enviromental conditions are kept optimal. 

The total increase in flowering period is only 40%, half the potential room for improvement. This means you don't have to be perfect to win out. 

Selective application of the 21:36/12 photperiod for only 1 or 2 weeks extends the wait only 2 to 4 Earth days, which makes up the missing 2 complete day and night cycles each week on Planet Ito. This permits the additional light energy to be provided without purchasing additional equipment or overloading existing circuits, which maximizes the existing system's capabilities. The main advantage is that matched with co2 and optimal nutrition, the plants metabolism will increase dramatically. I have only successfully tested this photoperiod for two weeks. The potential for a net increase of 40% over the entire cycle (80% increase in light energy vs. 40% longer wait) is worthwhile. Don't be afraid! 

Day 1 - Sunday, 6:00am til Monday, 3:36am 
Day 2 - Monday, 3:36pm til Tuesday, 1:12pm 
Day 3 - Wednesday, 1:12am til Wednesday, 10:48pm 
Day 4 - Thursday, 10:48am til Friday 8:24am 
Day 5 - Friday, 8:24pm til Saturday 6:00pm


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## bushmang (Sep 26, 2009)

sounds interesting i wonder if it really works. if im getting this right you give them 36 hrs of light and then 12 hrs of darkness and then 36hrs again? would be great if there was a time laps video or some pics of the buds etc.


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## Ghost420 (Sep 26, 2009)

what week in flower is this applied?


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## moash (Sep 26, 2009)

bushmang said:


> sounds interesting i wonder if it really works. if im getting this right you give them 36 hrs of light and then 12 hrs of darkness and then 36hrs again? would be great if there was a time laps video or some pics of the buds etc.


 no i think its 21:36 on and 12 off,stretching the flower time out so it can yeild more i.e 8 weeks takes 10


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## moash (Sep 26, 2009)

Ghost420 said:


> what week in flower is this applied?


 i suppose the beginning


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## wilsoncr17 (Sep 27, 2009)

moash said:


> i suppose the beginning


It would probably confuse the plant if you did it right away. It takes a plant at least a week to realize it's in flower, so if it wasn't getting the dark cycle in a timely enough fashion, it may never decide to flower, but I'm not sure, my Phd is in acting, not Rocket Surgery.


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## Don Gin and Ton (Sep 27, 2009)

ive read bout this but not quite the length of time so long as 21:36 only like 12/14 but seeing as most of the plant activity happens when the lights are off it only stands to reason longer dark = longer buds ive been thinking about trying this for a while but to truly know we need a side by side comparison 2 tents say same strain nutes medium etc 2 light cycles. 

if i had a second tent id have done it by now and im changing mny strains every month or so so its not really an option.

anyone else with two grow areas that would be able to try this id be real interested to see the results. 

rep moash


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## Redeflect (Sep 27, 2009)

For simplicity rather than 5 nights a week, someone could do less and 6 nights a week... 

6 hours on 12 hours off (total of 6 28 hour days during the week).

Every day, you would just shut off the lights 4 hours later. It wouldn't take as long as with a 21:36/12 cycle to reach the end of flowering (only about 15% longer, as opposed to about 40% longer)


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## moash (Sep 27, 2009)

wilsoncr17 said:


> It would probably confuse the plant if you did it right away. It takes a plant at least a week to realize it's in flower, so if it wasn't getting the dark cycle in a timely enough fashion, it may never decide to flower, but I'm not sure, my Phd is in acting, not Rocket Surgery.


 that could be...or it will take longer to start flower thus increasing time to elongate


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## moash (Sep 27, 2009)

Don Gin and Ton said:


> ive read bout this but not quite the length of time so long as 21:36 only like 12/14 but seeing as most of the plant activity happens when the lights are off it only stands to reason longer dark = longer buds ive been thinking about trying this for a while but to truly know we need a side by side comparison 2 tents say same strain nutes medium etc 2 light cycles.
> 
> if i had a second tent id have done it by now and im changing mny strains every month or so so its not really an option.
> 
> ...


 i would like to try too but only got one closet to use
maybe 2 diff grows with same strain and conditions will give a round about answer and its more reasonable


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## Don Gin and Ton (Sep 27, 2009)

yeah i think its wishful thinking moash co ordinating one grow let alone two for us bunch of stoners.....


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## Brick Top (Sep 27, 2009)

I have read different theories about light cycle manipulation before where the idea was to increase the hours of light in some ways at some times. I have never seen anything concrete about how beneficial, if beneficial at all something like that would actually be. I think it might fall into the category if ideas that work but also have some counterproductively to them that at times is worth it and other times it is not and I always felt this sort of thing fell into the not group. 
&#12288;
During daylight hours plants multitask, they allocate their energy and resources to virtually every function. During hours of darkness plants run on stored energy and they stop multitasking and allocate most energy to the most vital functions. Growth and THC production are two of those. 

Basically plants grow more efficiently in certain ways during hours of darkness and much less efficiently during hours of light so I have to think there is a balance point where if gone beyond you could lose instead of gain. 

THC in part works as a sunscreen and is broken down by light so while you extend overall energy intake to the plant you increase THC degradation. That means the plant has to replenish that much more lost THC during the hours of darkness than normal but then still have to be able to make more so there is that slow gradual increase.

I tend to expect that someone would need some mighty highfalutin gadgetry to find the balance point and then find out how much it would effect different strains, if it was not an even equal sort of effect. 

I&#8217;m pretty sure there is something out there that is better than the standard light cycles but it may come down to will the difference in results be enough to justify making the change?


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## moash (Sep 27, 2009)

in the quiet words of the virgin mary....cum again
i gotta give it to ya brick...u always say some fly ass shit
i didnt think about thc degradation....
+rep


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## Don Gin and Ton (Sep 28, 2009)

thats some informed info right there bricktop. i wonder if you could counter the counterproductivity with uvb?!? as you say it would probably require some piece of fancy machinery to know exactly


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## bushmang (Sep 28, 2009)

i remember reading in high times about this box this Canadian dude made that controls 8 lights but turns them on and off based on temperature and has a cycle for the on off thing so that a when a light turns off it makes sure it cycles them for an even disburse of light. the article is called yield of dreams

http://www.zinio.com/reader.jsp?issue=416078335&pss=1

its on page 52 check it out might be a better alternative. in this system they also finish two weeks later than usual but covers a huge area with lower amounts of wattage used and the yield seems crazy.


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## Redeflect (Sep 28, 2009)

You could always alter the light cycle to 16/12 to give the plant more daylight and energy in the beginning and during the two growth spurts (week 2 and 5 usually). During regular budding leave it at a simple 12/12. During the last 2 weeks when the plant focuses on maximizing resin running 12/16 to give it lots of night time and very little THC degradation.(Just as people sometimes use MH during the last week or 2 to increase resin, giving more darkness may help as well).

This way you're giving it more energy when it's growing a lot, and getting it into the habit of thinking it needs lots of "sunscreen"(If that's what THC really is primarily for, that hasn't been proven)... and then at the end forcing it to resinate quickly with very little degradation.

The best plants are always grown by altering their environment to meet their needs.


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## degggz (Sep 28, 2009)

from my understanding ...... and shit who knows with this stuff......
But from what I have heard (I haven't tried but am about to ) if you were possibly looking for an early harvest
then you would start giving the plant more darkness to help the buds ripen .... but as for getting a bigger yield 
I don't know (how?)... plants need lumens to grow ... they dont get lumens at night .


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## degggz (Sep 28, 2009)

oh lol n/m I just read what brick top said , oops stoner mistake 
makes sense that they would store energy


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## Barrelhse (Sep 28, 2009)

wilsoncr17 said:


> It would probably confuse the plant if you did it right away. It takes a plant at least a week to realize it's in flower, so if it wasn't getting the dark cycle in a timely enough fashion, it may never decide to flower, but I'm not sure, my Phd is in acting, not Rocket Surgery.


"I'm not a Rocket Surgeon, but I play one on television."


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## fureelz (Sep 28, 2009)

With that cycle you can only do it for 1 week??, saturday it ends at 6pm and sunday it starts at 6am, 12 hours...wouldn't it shock the plant come monday if you were to continue the cycle?


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## Redeflect (Sep 28, 2009)

The cycle begins on monday at 6am.... the plant gets 12 hours of darkness 5x during the week... it ends on saturday at 6pm... and begins again on sunday at 6am... it doesn't shock the plant because there is no difference. You're forgetting that at 6pm on saturday night begins and it ends at 6am on sunday, when the plant is ready for its 21:36 daylight again.


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## fureelz (Sep 28, 2009)

makes sense...


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## svchop889 (Sep 28, 2009)

what about this start off your flowering with 12/12 to get it to strech and make room for the buds then switch to a 18/12 to grow big buds then switch to a 12/18 too fill them with thc and leave them in the dark for 48hrs at the end so that they use up there stored energy to increase thc content


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## Blue Moonshine1 (Sep 28, 2009)

im way to stoned for this thread... im posting so i can find it and read it before my wake and bake!!!!


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## Redeflect (Sep 29, 2009)

Svchop889... you basically just repeated what I said. Smart one aren't you?


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## svchop889 (Sep 29, 2009)

Redeflect said:


> Svchop889... you basically just repeated what I said. Smart one aren't you?


yeah but more simple for the stoned ones


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## reeferMaster (Sep 30, 2009)

it doesent make sense 2 run up your electricity bill so what i figue is do it like summer would transition them down slowly from 18/6 all the way down 2 12/12 and im even going 2 go lower 2 8on/16 off so i figure they will begin flowering probly around 14 on 10 off-12/12 and probly half way threw flowering i will begin 2 decrese lite period, the sun doesent al the sudden come on for 21 hours a day i dont c how the plants would like that maybe flouresents it would help. i wouldnt trust doing it 2 a seed plant , clone it would prrobly mae it go crazy and thc gets all sticky because it wants 2 catch pollen. so the longer it waits 2 get impregnated the stickyier shell get, its all about letting the bud mature.


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## Redeflect (Sep 30, 2009)

Humans have a natural circadian rhythm of 25 hours... so even though the earth spins in 24 hours we naturally want it to spin in 25. There is nothing to say giving the plants a "day" of more than 24 hours would bother them.


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## moash (Oct 1, 2009)

reeferMaster said:


> it doesent make sense 2 run up your electricity bill so what i figue is do it like summer would transition them down slowly from 18/6 all the way down 2 12/12 and im even going 2 go lower 2 8on/16 off so i figure they will begin flowering probly around 14 on 10 off-12/12 and probly half way threw flowering i will begin 2 decrese lite period, the sun doesent al the sudden come on for 21 hours a day i dont c how the plants would like that maybe flouresents it would help. i wouldnt trust doing it 2 a seed plant , clone it would prrobly mae it go crazy and thc gets all sticky because it wants 2 catch pollen. so the longer it waits 2 get impregnated the stickyier shell get, its all about letting the bud mature.


 cloning it make it go all crazy?what?
i believe the pistils r used to catch pollen...


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## jberry (Oct 1, 2009)

reeferMaster said:


> it doesent make sense 2 run up your electricity bill so what i figue is do it like summer would transition them down slowly from 18/6 all the way down 2 12/12 and im even going 2 go lower 2 8on/16 off so i figure they will begin flowering probly around 14 on 10 off-12/12 and probly half way threw flowering i will begin 2 decrese lite period, the sun doesent al the sudden come on for 21 hours a day i dont c how the plants would like that maybe flouresents it would help. i wouldnt trust doing it 2 a seed plant , clone it would prrobly mae it go crazy and thc gets all sticky because it wants 2 catch pollen. so the longer it waits 2 get impregnated the stickyier shell get, its all about letting the bud mature.


it seems like your idea would use more power, not less....
and i dont understand your thinking on the whole clone/seed thing either?


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## reeferMaster (Oct 1, 2009)

i meant clones grow alot crazyier then seeds and u dont have 2 worry as much about hermies so it would be easy 2 use a clone 2 test out the stress factor and change the lighting as often as you want 2, the light does not decrease thc becuase the bud is always buling over itself in layers, i guess the pisols could help with pollination bud either way it goes 2 the bud pod. i belive pollens actually caught buy the crystals on the pod becuase u dont need hairs when growing weed hairs die any way 2 a pollinated bud pod. using a digital timer can manipulate all the cycles. i was explaing a 24 hour.15 min on/off timer. sicne night is important 2 growing why dont we have a longer night period as well as a longer day period for instance 20 on and 10 off 4 veg and maybe 16/12 2 begin bud so then u will not have 2 switch it back and forth at the end of your period. seems like the profesional growers here dont wana give up thier secret, i would imagine it would be better 2 duplicate a normal summer and maybe give it a little tweaks. but what about out door only getting about 6-9 hours of full sunlight? im thinking it would be better 2 have a few low watt halides or flouro side light s on 12/12 and have hps in the centter come on for 10 hours inbetween the 12/12 . i think this would simulate a normal day. im just obsessed with the plants growing natraully becuase thats how i belive in it grow the best for me.


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## moash (Oct 1, 2009)

reeferMaster said:


> i meant clones grow alot crazyier then seeds and u dont have 2 worry as much about hermies so it would be easy 2 use a clone 2 test out the stress factor and change the lighting as often as you want 2, the light does not decrease thc becuase the bud is always buling over itself in layers, i guess the pisols could help with pollination bud either way it goes 2 the bud pod. i belive pollens actually caught buy the crystals on the pod becuase u dont need hairs when growing weed hairs die any way 2 a pollinated bud pod. using a digital timer can manipulate all the cycles. i was explaing a 24 hour.15 min on/off timer. sicne night is important 2 growing why dont we have a longer night period as well as a longer day period for instance 20 on and 10 off 4 veg and maybe 16/12 2 begin bud so then u will not have 2 switch it back and forth at the end of your period. seems like the profesional growers here dont wana give up thier secret, i would imagine it would be better 2 duplicate a normal summer and maybe give it a little tweaks. but what about out door only getting about 6-9 hours of full sunlight? im thinking it would be better 2 have a few low watt halides or flouro side light s on 12/12 and have hps in the centter come on for 10 hours inbetween the 12/12 . i think this would simulate a normal day. im just obsessed with the plants growing natraully becuase thats how i belive in it grow the best for me.


 http://www.mellowgold.com/grow/mjbotany-removed/marijuanabotany1.html


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## reeferMaster (Oct 1, 2009)

yes that is true, so now i belive that the pollen is caught by the hairs it actually makes sense now. i thought the sticky crystals is what did it but looking throught the micro scope the hairs also have little tiny amber crystals on them, thanks for the link haha ive read al this stuff before, doesent hurt 2 read things twice.


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## moash (Oct 1, 2009)

no prob
go to chapter 1 and start
pretty nice info
or u can download it.....http://www.filestube.com/7acfc9f03471ff1f03e9,g/Clarke-Robert-C-Marijuana-Botany-An-Advanced-Study.html


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## reeferMaster (Oct 7, 2009)

haha im 2 busy2 be researching, what i would like 2 know is whats the best time for indoor lighting, like what strains need how much light and how many hours it takes 2 produce big buds, i think 12/12 is by far best. ive heard of decreasing it half way through budding down 2 8 hours


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## FrontaLobotomy (Oct 7, 2009)

When I was first learning how to grow, I used to bring the light period down to 8 hours for the last 3 weeks or so of flowering. Though I've yet to find anything conclusive that would point in the direction of it improving the yield over a 12 hour light period. If anything it maybe brought the satvia genetics in a week or so earlier, but that was about it. The most significant factor when it comes to large yields is space, the more space the more the plant can grow.


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## DrDank (Oct 15, 2009)

I have tested and tried the 21/12 photoperiod, aka Planet Ito by Mister Ito (from overgrow?), and although it sucks up more electricity, I _have_ noticed a difference in yields. I understand that plants stop using the light around 18hrs, but it's the only way to program the digital timer. It's almost impossible to the lights on/off manually, without screwing it up.
You don't need to run for the whole flo cycle, a week or two is enough, but I suppose going longer might push them even more. I've done it with flo's to get pre-flower going, and then move them under a 400w for 12/12. I've done it with the 400, but the heat rises to above 90°F, so it's tough to balance. I would like to try it with a dimmable 600w ballast, running 50% for a couple of weeks (2-3 ito cycles) and then switch back 12/12 at 100% power.


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## moash (Oct 15, 2009)

DrDank said:


> I have tested and tried the 21/12 photoperiod, aka Planet Ito by Mister Ito (from overgrow?), and although it sucks up more electricity, I _have_ noticed a difference in yields. I understand that plants stop using the light around 18hrs, but it's the only way to program the digital timer. It's almost impossible to the lights on/off manually, without screwing it up.
> You don't need to run for the whole flo cycle, a week or two is enough, but I suppose going longer might push them even more. I've done it with flo's to get pre-flower going, and then move them under a 400w for 12/12. I've done it with the 400, but the heat rises to above 90°F, so it's tough to balance. I would like to try it with a dimmable 600w ballast, running 50% for a couple of weeks (2-3 ito cycles) and then switch back 12/12 at 100% power.


 awesome
thanks for chiming in
i didnt think anybody was ever gonna come in with experience in this


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## Don Gin and Ton (Oct 16, 2009)

brilliant post man kool im thinkin ill get a digi timer n get to work. so 2-3 weeks in the middle of the 9 should be golden or would you recommend the latter 2-3 weeks when most of the filling out occurs?

rep+


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## Redeflect (Oct 16, 2009)

If plants "stop using light around 18hrs" then why didn't you put it on a 16/12 cycle... your math logic fails which means your scientific analysis of the grow was a fail too.


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## kings**t (Oct 16, 2009)

so could i throw my 6week old pants in 12/18 for the last two weeks and 48 for the last two days that will not hurt the plants even tho i had them on 12/12 for the last 6weeks


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## Don Gin and Ton (Oct 16, 2009)

shouldnt do. but im guessing that as were all trying to mimic nature here id probably put the longer light period at the beginning of the plants cycle as if it were the longer days of spring.


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## 420pharms (Oct 16, 2009)

this is very interesting but i fear tampering with 12/12 i cant fuck up and stress plants into hermis this type of expirement is somthing i need to get a r&d tent for same place id flower males in for pollen harvest but way beyond my current skill level i will pay attention to this topic please keep posting


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## Kcar (Oct 16, 2009)

plants need 12hr dark to keep budding. Not so with light. More hours of light will not stop budding.
the reason for 21:36/12 is because it's possible to program this into your digital timer, making it a no brainer...


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## Brick Top (Oct 16, 2009)

The title to the thread is; "*increased yeild with photoperiod."* Is this only theory or is there some sort of actual scientific proof behind this?
&#12288;
Myself, I do not see where there could be an actual net gain.


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## Don Gin and Ton (Oct 16, 2009)

why not? more dark time more growth?


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## Green Cross (Oct 16, 2009)

Don Gin and Ton said:


> why not? more dark time more growth?


No more energy more bud. Less light (energy) less bud 

"The only photoperiod manipulation from years of experiments that offered discernible improvements was the following photoperiod adjustment made for 1 or 2 calendar weeks at the point of maximum flowering rate:"

This sounds scientific and definitive, but where's the proof. Anyone here want to ruin their crop experimenting...? lol

I've been thinking changing from 12/12 to 14 daylight may increase yeild. In theory that should work too.


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## Don Gin and Ton (Oct 16, 2009)

i thought it was same light more dark as plants did most of the growing/ using the nutrients etc then?


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## Rocho616 (Oct 27, 2009)

Sorry if I seem rude but this is retarded... I mean seriously let me help you out; INSTEAD of trying shortcuts let it finish right and be ripe, if you want a faster flower i suggest you do you're research on aeroponics and nebulisers. But on a scientific note plants produce calyxes for and all that for the first 1-10 weeks slows down bad after week 8'ish....because at this point it has reached full maturity and whats happening is the trichs are turning amber and producing as much resin as possible....also plants produce resin in their dark period= more dark=more resin=better pot. CO2+Aero will give you some big crops if thats what you are after. 

and as always diff. strains very. Again sorry if i seem rude but 80% of growing screw up's are because of shortcuts and impatience.


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## Brick Top (Oct 27, 2009)

Green Cross said:


> No more energy more bud. Less light (energy) less bud


*That is the flaw in the whole idea. As I have said before during hours of light plants take in as much light and transform it into energy as they can. During hours of light the plants will multitask, they will allocate energy to all functions, including saving energy for use during hours of darkness. 
&#12288;
During hours of darkness plants stop multitasking and allocate all their stored energy to just a few primary functions and growth and THC production are two such primary functions. Because of that those functions are allocated more energy during the hours of darkness than they get during hours of light so they grow faster and more efficient and they produce more THC faster and more efficiently. 
&#12288;
There is also the loss of THC to factor in by increasing the amount of light plants get while still tricking them into believing they are in an regular flowering time cycle. 
&#12288;
Light degrades THC, one primary function of THC is to work like a sunscreen for the trichome-head to protect it from the suns/grow lights damaging rays. During hours of darkness when THC is produced more efficiently and at a faster rate the lost THC is replenished and then a small additional amount more is made so you have a slow gradual increase in THC levels by plant maturity. 
&#12288;
But if you extend the hours of light when in the 12 hours of darkness what is the assurance that the plant will be able to make up for the additional amount of THC lost to light degradation and then on top of that still be able to produce the small additional amount of THC that should be produced? 
&#12288;
By manipulating the time in such ways at what point might someone reach a point of diminishing returns and at what point might they go beyond just diminishing returns and end up with a net loss? 
* 


> I've been thinking changing from 12/12 to 14 daylight may increase yeild. In theory that should work too.


 
*Did I miss something in the above or did you just say that you are planning on going from a 12/12 flowering lighting cycle to a 14/10 lighting cycle where the hours of darkness would be less than 12 hours long and you say; "*In theory that should work too*" or did you mean you will be going to a 14/12 lighting cycle and do away with the whole 24 hour day concept? 
*


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## DrDank (Oct 31, 2009)

Redeflect said:


> If plants "stop using light around 18hrs" then why didn't you put it on a 16/12 cycle... your math logic fails which means your scientific analysis of the grow was a fail too.


hehe, you mistake me for an _actual_ doctor. 

I've only tried the schedule listed in this thread, which has floated around for some time. By all means, if you have a more energy efficient schedule that's programmable on a 7-day timer, I'm willing to try it. The ChinaFarm digi only allows for a certain amount of on/offs.


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## wowisuckatthis (Oct 31, 2009)

Brick Top said:


> *That is the flaw in the whole idea. As I have said before during hours of light plants take in as much light and transform it into energy as they can. During hours of light the plants will multitask, they will allocate energy to all functions, including saving energy for use during hours of darkness. *
> *&#12288;*
> *During hours of darkness plants stop multitasking and allocate all their stored energy to just a few primary functions and growth and THC production are two such primary functions. Because of that those functions are allocated more energy during the hours of darkness than they get during hours of light so they grow faster and more efficient and they produce more THC faster and more efficiently. *
> *&#12288;*
> ...


 nicely said brick! why screw with a good thing, earth has a 24 hour day leave it alone people.


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