Photoperiod for Larger Yields

I read about in the grow faq. Do people commonly practice manipulating the photoperiod for 1 to 2 weeks during flowering. If so how do you when to switch to 21/12.... Anyone messed with this before?

yeah i would like to know more about this aswell....

When I get down to the last few weeks of 12/12 I start dropping the time down by one hour each week until I get to 8 hours of light a day. Cant say that it makes a difference or not, but just what I have always done. I cant complain about the results, it works for me so I stick with it.

Thats interesting rkm... I more curious about adding more hours of light... I dont see the benefit of subtracting light... P.S. Where you high when you posted that?

flipsidesw said:

I read about in the grow faq. Do people commonly practice manipulating the photoperiod for 1 to 2 weeks during flowering. If so how do you when to switch to 21/12.... Anyone messed with this before?

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Depends on what you want your plant to do ie; veg or flower. In flower you can switch the hours to 14/10 to speed up ripening of the flowers or in veg you can leave them on for 24/0 for veg or if it's your mother. All depends on what you want your plant to do. KEEP SMOKE ALIVE!!

I read somewhere that if you stress WW for the last two weeks of flowering, (no lights at all), she strains her resins BIG TIME and the growth rate is really good. Have not tried it yet, but sounds intriguing. Must work on other strains as well IMO.

i do this method and the way i understand it and what seems to work for me is:
i shorten the daylight period over the last little bit of flowering time to 10 hours. i have read that any less and they stop producing thc. the idea is that the plant will think it`s late fall and will want to naturaly reproduce itself, so it speeds up the final resining and sort of seals up the buds. but before they can start making flowers to reproduce you take it down. if you increase the light at the end it will most likely hermie.

i dont know if you mean at the end like this or do you mean at the begining of flowering going from 18/6 gradualy down to 12/12. if so that dosn`t do anything except drag the veg on longer and delay our mission, BUDS

flipsidesw said:

Thats interesting rkm... I more curious about adding more hours of light... I dont see the benefit of subtracting light... P.S. Where you high when you posted that?

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I wasnt at the moment but was working on it. My thinking is If you were doing 18/6 for veg and it takes 12/12 to make it start flowering, why would you go back the other way giving it more light? The idea of cutting the lights down is to simulate the shorter days at the end of the season, not to make the plant think spring is on its way again. In my mind working it down steadily to 8 hours of light a day hopefully tells the plant to get its ass in gear because the cold is really on its way and better finish reproducing quickly. Sometimes I dont make it to the 8 hour length, if the plant finishes before I get there then I harvest. I dont set that gradual decrease to 8 hours goal in concrete, its just a guide that I use.

I appreciate you guys replyin' but would you please read the GROWFAQ... Its about adding more light when in full bloom... From what i take from it you would start adding the extra light around week 6.... The idea was to get more growth during daylight hours putting off harvest up to a week.... The photoperiord would be 21:36/12.... Peace
Read the article before posting.. Hopefully someone who has done this will reply..
growfaq>advanced cultivation techniques>Improving yields>larger yields> READ IT>Post.....

flipsidesw said:

I appreciate you guys replyin' but would you please read the GROWFAQ... Its about adding more light when in full bloom... From what i take from it you would start adding the extra light around week 6.... The idea was to get more growth during daylight hours putting off harvest up to a week.... The photoperiord would be 21:36/12.... Peace
Read the article before posting.. Hopefully someone who has done this will reply..
growfaq>advanced cultivation techniques>Improving yields>larger yields> READ IT>Post.....

Click to expand...

Then why did you even waste space posting this asking for opinions if you only want answers that agree with the FAQ? Just go with the FAQ and see if you are happy with the results, you dont need our input for that. Besides, the FAQ is on the internet so its gotta be true.

I do want opinions. Thats why i posted it. Im just hoping to get feed back from someone that has tried it. I thought that was what this website was about..

I would take that grow faq with a rather large grain of salt and it should most definately NOT be considered the final authority of growing pot.

I go from 24 hour light (marijuana does not need to "rest") and right into 12/12 for the flowering duration. What you should not do is cut back to a 10/14 cycle, this lessens the amount of photosynthetic activity and some studies and research have shown a decrease in THC production (source: Marijuana Botany page 123).

If you do go with a longer light cycle, say 14/10, then on top of the potential yield you need to add in the cost of the extra grow time. If you have an 8 week plant then you'd need to get an extra 12-15% yield to make it worth while if the plants take 9 weeks to mature, for example.

It says 40% for only 4 extra days... Pretty dope... I have to try it.. If you think about it at or at least from what i know it takes a certain amount a 12 hour dark periods for a plant to be ready for harvest.. I would guess thats predetermined by genetics, that being said why not give the plant some extra hours of light to fatten up.. I really think there something to this theory. I wish i was more educated. When i get to week six im gonna do 21:36/12 and see what happens.. I already have a hermie what harm could it do..

i flowered for an entire week on a different schedule of 12/12 and it didnt make anything go quicker, or slower.....

to start with if you already have a hermie watch it dosen`t pollenate the rest and end up with all seeds.
here`s some evidence to back my theory, i geusse we need to take the sientists with a grain of salt also.

source: shadowace

72Hrs Darkness before harvest
increases THC in the Bud
The Stichting Institute of Medical Marijuana (SIMM), the first company to sell marijuana through the pharmacies of Holland, has been investigating the medical possibilities of cannabis, together with TNO laboratories and the University of Leiden. One of their discoveries has been that to keep the ripe plants in the dark before harvesting could increase their potency.
SIMM’s growers separated a crop of mature plants, harvested half of them and kept the other half in absolute darkness for 72 hours before cutting and drying. Analysis of the resulting dried buds showed that some varieties had seen an increase of THC of up to 30%, while CBD and CBN remained the same.





THE PROCESS
The biosynthesis or production of cannabinoids in the plant follows a chemical process in which some cannabinoids are converted into others. First produced is CBD, which is transformed into THC, and finally into CBN. For this reason plants harvested before their time will contain more, CBD will not have reached its peak. On the other hand, those picked a little late will have more CBN than CBD, and will now have lost some of their THC. There is a perfect moment of ripeness, where the maximum THC is available for the savvy harvester. This can be judged by watched the color of the resin glands - when they start to turn yellow or amber, it’s time to cut, hang and dry.

FAST OR SLOW?
We want fast, nature wants slow. Plants need space to grow in, and time. Further time is needed for drying. Human impatience, either for the buzz or for the profit, and the extreme pressure of growing under prohibition, has shaped our cannabis market to suit its own ends, rather than those of us consumers. For exampe, has led to a preference for indica strains (eg Northern Lights) over sativa, because they grow faster and are smaller, needing less space. Plus they win out in the THC stakes - a stronger, more immediate, and ‘heady’ buzz. (Interestingly, under prohibition of alcohol in the USA, consumption of beer fell while that of hard liquor rose you can get more dollars for a car boot full of illicit whisky than three or four of beer. Less to carry, easier to hide during transport, and at home too. This circumstance produced more alcoholics at a faster rate, since people were now drinking to get drunk rather than sit around enjoying charming flavours.) In a legal market, extra time and extra space would not be at such a premium and consumers would find a wider range of plants, and arguably, much greater delight, on the market. So, if you want a weed that gives more than a fast strong buzz, you’ll have trouble finding that on the black market. Yet another case of: ‘if you want something done properly, do it yourself’. There are plenty of sativa seeds out there looking for good patient homes. Stop choosing the ones with the shortest grow periods! OK, they’ll take a little longer, and a bit more room, but you may be very pleased with results.

flipsidesw said:

It says 40% for only 4 extra days... Pretty dope... I have to try it.. If you think about it at or at least from what i know it takes a certain amount a 12 hour dark periods for a plant to be ready for harvest.. I would guess thats predetermined by genetics, that being said why not give the plant some extra hours of light to fatten up.. I really think there something to this theory. I wish i was more educated. When i get to week six im gonna do 21:36/12 and see what happens.. I already have a hermie what harm could it do..

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The fact the the FAQ says "40% for only 4 extra days" is the reason that this FAQ needs to be taken with a grain of salt.

Thanks for that bro
ill keep that in mind... Anyone out there willing to touch the topic of this forum?

I posted a question concerning that same article in the faq. Nobody really had any answers for me. The way I remember, it wasn't very clear as to what it meant by 40%. The first time I read it, I took it to mean 40% greater yeild. I went back and read it later and thought the author was trying to say that the plants get 40% more light energy and therefore may have more grow potential accordingly. I had thought about trying this, but since the plants in my flowering room were in different stages of bloom, it would have been too difficult. I know that if you switch to 14/10 during flowering, you are supposed to have a greater yield, but flowering takes longer and buds are supposed to be more leafy. If you decide to try that 21/12 schedule or whatever it is, be sure to let us know how it turns out. I would be really interested to hear. Where the hell do they sell timers that would work for a schedule like that anyway?

Ya i totally feel what ur saying. I didnt think i would get and extra couple of ounces lol. I figure its worth trying. I think the best time to start the 21:36/12 would be right around when the buds really start to form. Like week 6 wouldnt you agree that would be the time to try it?

crotalus said:

I know that if you switch to 14/10 during flowering, you are supposed to have a greater yield, but flowering takes longer and buds are supposed to be more leafy. If you decide to try that 21/12 schedule or whatever it is, be sure to let us know how it turns out. I would be really interested to hear. Where the hell do they sell timers that would work for a schedule like that anyway?

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The 21/12 or something close could possibly work. The photo period is determined by the amount of darkness not the amount of light. It's a rather interesting idea.

You'll likely have to build your own timer in this situation using a microcontroller. I'm going to give this a try with a plant to see what happens.