they will flower on 14 hours much the same as 12 hours, i didn't notice any difference i thought it might make them grow
more before budding but i couldn't see any difference
they will not re-veg unless they get 16 hurs, maybe 15 could work too for veg
i have never tried a 15 hour photo period so not sure what would happen on one
the theory is giving them more light will increase yield as you are increasing the overall photosynthesis while maintaining
enough of a dark period to keep them flowering , i remember reading something written by good old ed rothenthal about this
he said, he was aware it can be taken upto 14.5 hours on, and that it was common for plants outdoor in certain regions in the USA to only have a 9.5 hour natural dark period outside and flowering was induced with no problems with mainly indica varieties grown outdoor
the 12/12 is only a standard that will allow all weed plants to flower whatever their origins are it is said to be the best balance
i do not think you can achieve that much by playing around with the 12/12 standard since going below 12 to 11 or 10 hours on will decrease yield
going upto 14 will not increase it as far as i can see , maybe you will have different results
good luck
![Smile :) :)](/styles/smilies/icon_smile.gif)