# photoperiod manipulation for larger yeild



## satan's dalmation (Feb 15, 2009)

Anlone ever try this?

larger yields

*How do I manipulate the photoperiod for larger yields*


*[DISCLAIMER]: This information is provided as experimental data and not fact.* 

The only photoperiod manipulation from years of experiments that offered discernible improvements was this 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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## doctorchaos555 (Feb 15, 2009)

That's funny because I'm doing this same experiement with different light times.


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## Jeffdogg (Feb 18, 2009)

I'm increasing the light cycle by a half hour for the last 2 weeks of flowering (starting today actually) In a grow vid (THC Seeds one) a dude was saying it increases THC potency as well as helps produce a bigger yield.


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## satan's dalmation (Feb 18, 2009)

as many problems as i had im scared to try it. was looking for some feedback from a someone with bigger balls than mine thats done it.


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## Jeffdogg (Feb 18, 2009)

yeah it sounds interesting would like to hear some feedback on that way myself. But doing it the way I'm gonna do it from what I understand leaving it on that extra time (30 more minutes in my case) is gonna tell the plants the season is about to change (reaching the end of its life cycle) and kinda put em in over time I guess. we should keep up with this thread with our progress my light cycle change starts today 12:30/11:30


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## doctorchaos555 (Feb 18, 2009)

I don't remember where I read this and don't even know if its an actual fact but there was something I read that explained how a plant recongizes when to veg and when to flower not based on how much light it gets, but how much dark time it receives. Theres a supposed chemical process that occurs at night and when the plant recognizes that theres a certain amount of night, then it should start flowering or whatnot. It's interesting because what if you doubled the energy that it absorbs in a "day"? Another interesting point is it can help find out more about photocycles for plant life on other planets cause well, plant life seems to start with the light cycles and its manipulation. Keep it up man, I'm subscribed. I got my baby under 12/12 right now waiting for sex signs. But when I find out it's sex and it's female, i'm gunna up the light cycle to maybe 24/12 or 18/12, or even 36/12, to see if the absorbing energy makes a diff. Also another thing I read is that plants grow at night with the energy they collect during the day. I'll let you know how my findings are as well.


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## noltnercr03 (Feb 19, 2009)

Have you guys really seen increased yields by having a control plant that goes the regular 12/12 or are you just doing it with the entire grow?


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## doogleef (Feb 19, 2009)

I doubt seriously that it would increase yield or THC. A lot of people say a lot of things but that does not make them so. Messing with the light cycle causes stress. Stress in prime flower period is bad. Causes hermis in a lot of strains. 

18/6 VEG
12/12 Bloom

Works for thousands of professionals.


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## satan's dalmation (Feb 19, 2009)

I veg 24/7 under floros. Im sticking with 12/12 for flower until i see proof that this will work. It is tempting though to get a higher yeild using the same equipment, just by setting the timers different. And i agree stress = BAD. I had to pull a lemon skunk that started throwing male flowers about 3 weeks before it was ready. only about 25% of pistisl turned and bam! yellow damn nanners. I kept them trimmed off everyday for about a week, but started getting to many. Didn't wanna risk missing one.


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## slingblade (Feb 19, 2009)

i never tryied that my hybrids are 4 weeks in so wait 2 weeks n give 30 min extra sounds good


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## Jeffdogg (Feb 19, 2009)

slingblade said:


> i never tryied that my hybrids are 4 weeks in so wait 2 weeks n give 30 min extra sounds good



Its my second 12:30 cycle tonight i'll keep ya posted let ya know how it goes


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## uwhcmw76 (Feb 19, 2009)

I sounds like a solid idea and in theory should work if the 12hrs of darkness is what keeps it in flower, so I think that I will take 3 clones and give it a try on the next grow, besides I figure worse case scenario is the plant reverts back to veg and it sets you back a month but either way higher yields. do you think that it would be best to stage it up to that point or just go from 18/6 to 12/12 to 21.36/12? also where did that number come from 21hrs 36 min seems like a weird number why not just 21hrs or 21.5hrs


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## IslandGreenGuy (Feb 19, 2009)

I've grown the same strain from clones now for the past 4 grows. I tried doing 13 hrs on 11 off last grow and I did see a slight increase in yeild. this could have been that I have become a better grower, but I think it may have been the lighting. My current grow is on 12/12 and will ending in a few days. Lets see what happens.


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## Jeffdogg (Feb 20, 2009)

IslandGreenGuy said:


> I've grown the same strain from clones now for the past 4 grows. I tried doing 13 hrs on 11 off last grow and I did see a slight increase in yeild. this could have been that I have become a better grower, but I think it may have been the lighting. My current grow is on 12/12 and will ending in a few days. Lets see what happens.



Cool bro, the vid I watched that told me about that said on some strains the light cycle can go up to 14 hours of light the last 2 weeks. I didn't wanna push it so I'm just doing 12:30 to try out


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## ihaveadream (Feb 20, 2009)

doctorchaos555 said:


> I don't remember where I read this and don't even know if its an actual fact but there was something I read that explained how a plant recongizes when to veg and when to flower not based on how much light it gets, but how much dark time it receives. Theres a supposed chemical process that occurs at night and when the plant recognizes that theres a certain amount of night, then it should start flowering or whatnot. It's interesting because what if you doubled the energy that it absorbs in a "day"? Another interesting point is it can help find out more about photocycles for plant life on other planets cause well, plant life seems to start with the light cycles and its manipulation. Keep it up man, I'm subscribed. I got my baby under 12/12 right now waiting for sex signs. But when I find out it's sex and it's female, i'm gunna up the light cycle to maybe 24/12 or 18/12, or even 36/12, to see if the absorbing energy makes a diff. Also another thing I read is that plants grow at night with the energy they collect during the day. I'll let you know how my findings are as well.


Yes plants collect light during the day and they actually do there growing at night. Just read it in biology book and it was talking about seeded flowering vascular plants or angiosperms.


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## spiked1 (Feb 21, 2009)

I've read this quite a few times, both here and on other forums,
It's been talked about over and over but I'm yet to see anyone
post that they have actually tried it, or results of any kind.
So for this reason I take it with a grain of salt.


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## Gdaddy (Feb 21, 2009)

In last months High Times they had an article about a "master grower" somewhere in Cali. He sets his lights to 13 on and 11 off about 2 or 3 weeks into bloom for about 2 weeks, he says the extra light along with a bloom enhancer like Big bud or something like it sends the buds into overdrive. He also kills the lights for 72 hours right before harvest, says it increases flavor and coloring dramaticaly. I don't know about the 72 hour thing, that kind of scares me, but I'm going to try the 13/11 thing.


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## satan's dalmation (Feb 21, 2009)

i would be more afraid of the 13/11 period than the 72 hours right @ the end. 72 hours of dark right before the plants transforamtion, what could go wrong in that ammount of time. I actually will do this in the next couple weeks as soon as the trichs on my durban poison are done growing. i just wish i had another one to pull at the same time to compare it to vs one that stayed in "normal" conditions for the 72 hours.


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## Jeffdogg (Feb 21, 2009)

Finished 3rd night of 12:30/11:30, so far plants looking great. Their growth is quite noticeable on a daily basis still, and no signs of seeds


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## uwhcmw76 (Feb 22, 2009)

satan's dalmation said:


> i would be more afraid of the 13/11 period than the 72 hours right @ the end. 72 hours of dark right before the plants transforamtion, what could go wrong in that ammount of time. I actually will do this in the next couple weeks as soon as the trichs on my durban poison are done growing. i just wish i had another one to pull at the same time to compare it to vs one that stayed in "normal" conditions for the 72 hours.


not for sure but I think that the 72hrs of darkness is not for growth but to help the plant flush of chlrophyll since there is no light the plant stops making it and starts to also feen on reserve nutrients, also flushing it of other trace minerals


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## Jeffdogg (Feb 22, 2009)

uwhcmw76 said:


> not for sure but I think that the 72hrs of darkness is not for growth but to help the plant flush of chlrophyll since there is no light the plant stops making it and starts to also feen on reserve nutrients, also flushing it of other trace minerals



There was a thread similar to this not too long ago (started by myself I believe) I was wondering what people thought about me changing the light cycle to 12:30/11:30 and Doctor Cannabis mentioned that during the night the plants produce trichomes, which in turn during the day protect the plant against UV rays/heat and what not. The last 72 hours in dark is for potency/trichome production etc.


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## haze2 (Feb 22, 2009)

Island green guy thats a nice BOX of money, how much was there


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## justsaymint (Feb 22, 2009)

i put my plants on 10/14 10 light 14 dark for the the last week of their life and so far have seen amazing results


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## hectorius (Feb 23, 2009)

Gdaddy said:


> In last months High Times they had an article about a "master grower" somewhere in Cali. He sets his lights to 13 on and 11 off about 2 or 3 weeks into bloom for about 2 weeks, he says the extra light along with a bloom enhancer like Big bud or something like it sends the buds into overdrive. He also kills the lights for 72 hours right before harvest, says it increases flavor and coloring dramaticaly. I don't know about the 72 hour thing, that kind of scares me, but I'm going to try the 13/11 thing.


 
you mind pullin gout the article in wich you read this im interested now, as far as the 72 hrs light off at the end ive done it it does increase some thc but not significantly, but the taste changes. Also 48 hr darkness going into bloom speeds things up by about a week as it sends them into bloom really quickly. Ive done 11 on 13 off for the last 10 days before as soon as i started my flushing and ive had good results.


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## englandman (Feb 24, 2009)

im not a master grower but wouldnt you want to increase the dark time and increase the day time? so the plant think oh shit im losing more daylight. and i dont think the 72 hour thing would be good .. what about mold and stuff?


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## englandman (Feb 24, 2009)

so to do the 10light 14dark thing do you change its off time,, or its on time?


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## haze2 (Feb 24, 2009)

Id say off time.


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## hectorius (Feb 24, 2009)

by keeping your humidity levels low during those last 72 hrs is the key to success not only does it prevent bacteria and mold but it also helps dry out the soil so its not so heavy to throw out and helps with the drying of your nugs as the plant gets alot of its juiced dried out, making curing much more easier and faster.


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## SeriousSmoker (Feb 25, 2009)

interesting thread


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## satan's dalmation (Feb 25, 2009)

Going to check my crop today. This durban is taking forever for the trichs to turn. everyone that sees is wants to wack it down now it's sugary as hell but no amber ones yet. as soon as i see enough amber its in the dark for 72 hrs. FYI didn't forget about it just taking forever!!!!


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## Jeffdogg (Feb 25, 2009)

> everyone that sees is wants to wack it down now


How many people looking at your plant(s)? Did ya miss the first rule of growing? You should atleast charge admission that way when your plant(s) get boosted you'll have a little flow to make up for it


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## Greenisgold (Feb 25, 2009)

hectorius said:


> by keeping your humidity levels low during those last 72 hrs is the key to success not only does it prevent bacteria and mold but it also helps dry out the soil so its not so heavy to throw out and helps with the drying of your nugs as the plant gets alot of its juiced dried out, making curing much more easier and faster.


You do not want a fast dry or a fast cure unless you are a commercial grower. The slower the cure, the tastier the buds and the stonier they become. You want to cure in a jar for at least 1 month.
I have weed that has been in jars for minths and it keeps getting better and better, but there is a cut off point.


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## satan's dalmation (Feb 25, 2009)

just my 2 brothers. i don't have a big sign up "hey killer pot growin over here"


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## TeaTreeOil (Feb 25, 2009)

Anyone try non-24 hour photoperiods? Like 12/4 for veg(1.5 days per 1 Earth), or 20/12 for flowering(.75 days per 1 Earth)?


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## haze2 (Feb 25, 2009)

good question tea!


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## TeaTreeOil (Feb 26, 2009)

I'm experimenting with 12/4 veg.


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## haze2 (Feb 26, 2009)

Now you have to keep us posted!


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## Klo$etBreeder (Feb 28, 2009)

I've heard about the 72 hours of darkness at the end it is supposed to increase resin production. there is no possible way to increase potency that all depends on the genetics of your plant. you cant take shit and turn it to gold. i personally have increased my light cycle to 14/10 after seeing it in one of the urban growers vids and it was said to give about a 10 % increase in yeild and on a pound thats what an oz&1/2. something like that but smaller plants and smaller number of them you prolly wont notice the difference. But i totally agree with the increase in light the last 2 weeks and 72 hours of darkness but i flood my plants the last few days and then let them sit for 2 days so the soils dry by the time i hack. Every grower has there own tech's and what works for them. You never know thats the beauty of cannabis you make it your own and dont have to follow the rules


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## spiked1 (Feb 28, 2009)

When did you switch to 14/10,
and have you noticed anything peculiar since then?


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## englandman (Feb 28, 2009)

i had one guy tell me to do 14 light 10 dark for grow. then 14 dark 10 light for flower....


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## TeaTreeOil (Mar 2, 2009)

I left my lights on for two days straight as I had to go out of town for the weekend.

Impressive growth when I got back(much better than 2 days of darkness & 24/0 that I've done the past 2 weeks). Resumed darkness upon getting back and 12/4.

Almost my first CFL grow. After around a month of daily research on them... had to try them for myself.


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## ihaveadream (Apr 3, 2009)

I have a Purple Kush I am flowering I had it in veg for 3 months. It is in a 5G bucket and has 60 nodes which start opposite and the begin to become alternate at about node 28. This beauty Is definately past the 10 ounce yield mark and I believe it has alot to do with this light cycle I used it exactly as stated but gave it 13 hours of darkness toward the end. I also used gravity flower hardener from humbolt and i believe that also helped me out alot. Those Fuckin Nugs are Huge. Ill get a couple pics up later today.


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