How do I Manipulate the Photoperiod for Larger Yields

Cannabis flowering works on the dark period... not the light. I haven't played w/any of that, I'm more of an OD guy but... I do know that it's the dark not the light that promotes flowering and finishing.

In fact... not enough dark or even a light leak will ruin your finished product!
 
Exactly! Thanks Capn!

As long as you give your plants a 12 hour dark cycle, you can give them as much light as you want beyond the traditional 12 hours. When using an advanced timer like the iGS-15, you can run a 72 hour day if you wanted to.

This practice of extending the light/dark cycle beyond the traditional 24 hour day is already in practice in commercial agriculture. It is used to boost yields for HotHouse tomatoes, certain flower strains etc. It just hasn't been messed with much in the Cannabis circles. That's why I wanted to see what I could discover by trying it! Commercial automation control gear like the iGS-15 ain't cheap, but fortunately the guys at PlugNGrow hooked me up with a deal I couldn't refuse! ;)

I've got TONS of plants and plenty more where these came from, so if I loose a few plants, it isn't going to matter much to me. However, I am fully expecting an EXPLOSIVE harvest boost from this, with vibrant and healthy plants the entire time! :thumb:

Just stay tuned to this thread over the next 8 weeks, as I report on what develops during this experiment! :)
 
Hey guys I just wanted to share this;
for the past 3 weeks I've been using this photoperiod
started 12on/12off on 03/08/13
changed 11on/13off on 04/01/13
changed 10on/14off on 04/08/13
changed 9on/15off on 04/15/13
Will change 80n/16off on 04/22/13

So far this IS what I got. Keep in mind this is my first grow.

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I have seen an increase on the amount of THC crystals and a low branch development vs. abundance of new white pistils. I would say the increased dark periods are important during advanced flowering stage. I Will try longer dark periods to see what happens, see if I can reach a 24 hr dark with 8 hr light.
 
hi, has anyone actually tried this all the way to harvest

ive been interested in giving plants more than 24 hours per day but didnt know that you could give more day hours as long as you kept the 12 hours of dark,

i only came across this due to a member asking questions and telling us about this post,

i know its an old post but has anyone actually tried this method, plus how much light hours is to much, could for example we go 24-12 or even further say 30-12, its an interesting idea but need to see some proof or see some evidence to back the theory up,

so if anyone has tried it please give us a shout and let us know how you found it compared with a regular 12-12 harvest, i have wondered if something like 14-12 is good or something similar but 21.5-12 seems a bit much but if it works then how come more of us are not using this method or even heard of it
 
Hey guys I just wanted to share this;
for the past 3 weeks I've been using this photoperiod
started 12on/12off on 03/08/13
changed 11on/13off on 04/01/13
changed 10on/14off on 04/08/13
changed 9on/15off on 04/15/13
Will change 80n/16off on 04/22/13

So far this IS what I got. Keep in mind this is my first grow.

use this link for further information; How to Grow Marijuana

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DSC020573.JPG
DSC020544.JPG

Your plants are pretty weak looking. You should just stick to 12/12 and you flowered them way to soon.
 
plus you have a hermie, 3rd picture down, you see those banana shaped yellow things, well their female pollen sacs,

i think this is proof the method is not to be used, looks to me like you got hermies and the plants are not going to produce anymore than they have done,

get some seeds and get a grow journal up and we will help you produce some amazing plants, kill that hermie unless you just leave them to go to seed, but chances are the seeds wil turn into hermie plants,
id cut your losses, now ive had a closer look at the pics the plants look like they have been heavily defoliated, stressed and are now in hermie, this could just be down to you interupting the dark period as this causes hermie pretty quick.

but something dont look right, the pistils suggests the plants are much further into flower than they are, meaning the buds are not far off done, or it could just be that you have baddly under watered or heat stresses them causing the pistils to brown and shrivvel, it really dont look like you will be having much bud to harvest,

but you do have a hermie my friend, id check all your plants for signs of it been a hermie, those banana things in the 3rd picture at the top of the pic and in the bud in the bottom of the pic, those yellow banana things are female pollen sacs, these will open and spread pollen to all the plants, so check all plants for this, if it was me i think id kill the hermie and put the other plants back into veg schedule and start again, that will then give you something to work with, even under 12-12 you wont get much back from them plants, so id flip back to veg and let them go back into veg and then veg for a few weeks before going to 12-12,

thats about the best option i say you have at the minute, they might all be hermie, just have a good look
 
you can also flower plants 12-12 from seed but you will be lucky to get an 8th per plant to about a 1/4 per plant under 12-12 from seeds,

the other option would be autos, dont need any light schedule, just pick a schedule and let them do their thing, id say at this stage the light schedule have caused yours to hermie, some strains hermie really easy, plus im sure i read that this light schedule is only to be used once the plants are in full flower as its to late for them to go back to veg and its only to be used for 2 weeks then go back to 12-12 till harvest,

so maybe you started to early, either way you dont have much branch growth and hardly any fan leaves, it could just be a case of you done to much to them, removing leaves stresses them, so a combination of the 2 might be whats causing the problems your having,
 
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