i am very interested in this topic of finding the perfect light schedule for my babies. 12/12 is an AWESOME rule of thumb. but im sure some strains need less, some need more. as well. daylight savings time is coming up in a month or two and thats the perfect time to make a small adjustment to the timers, since there gonna be off an hour anyways, if you dont. so heres what im thinking that may help alot of us out. a whole lot of threads regarding this subject and nothing solid has been suggested. just tons of speculations, and people saying "keep us posted". well from what ive gathered after tons of browsing cannabis forums, is that sativas take longer (ofc) to flower, which also means they need slightly longer light cycles than indicas. since sativas are native to warm tropical areas, not only can they take the heat slightly better than indica's but they also need a little more darkness in the night cycle to kick flowering into gear. now if this is true, its quite possible heavy indica's could start flowering with a little over 12 hours of daylight (dont quote me)but after this consideration, i think if your growing primarily indica dominant hybrids (very low sativa content, if any) inside and need to manipulate your lighting to induce flowering. going 12.5/11.5 could be a good idea. i would LOVE to hear if someone has tried this, if not i certainly will. an extra 30 mins a day of light= 3 extra hours of light on your ladies per week. 12 extra hours a month, a full day squeezed in legitimitely. BUT i know some people people SWEAR by 12/12 even tho nature only has 2 days of the year like that. i know this is an old thread, pm if you have any good advice on this idea. id prefer to wait on advice but i also plan on trying it no matter what by daylight savings time november 8th
I do know about 9 hours of darkness is enough to induce flowering, though I would recommend closer to 12 hours. I can't substantiate my theory, but I believe an extra hour of light or dark would not have significant effect on the plant. If you do experiment, I would definitely suggest staying within 3 hours of the 12/12 cycle. FYI, most of my indoor experience is with indica dominant strains. Good Luck!
sounds awesome, haha "keep us posted" no but seriously...i would love to hear your results the only thing....are you going to do a true side-by-side? (as in, one room with clones on 12/12 and another room with clones from the same mother taken at the same time with the same nutes and everything else the same except on 12.5/11.5 lighting) or is it just one room? with just one room your results may be less conclusive i do remember seeing on the internet someone did a true side-by-side with one flower room on 12/12 and another with LESS light, 10/14....to see if it would flower faster...or i guess the effects in general long story short, the 10light/14dark flower room yielded MUCH less than the 12/12, and it took just as long so, with that in mind, you would think extra light would help get a bigger yield...just as long as the extra light doesn't kick the plants back into veg and like you said, some strains can take more light in flower, some can't....depends on strain but that was just someone on the internet...who knows if it's true...it seems like scientifically sound reasoning, but i try not to believe anything with these plants unless i've tried it personally, and i have not done a true side-by-side comparing that myself
ahh, i got itchy, so i did some searching and here's what i found: here, they're saying some guys even go 13on/11off from weeks 2 to 6 of flower, for the extra yield... http://forum.grasscity.com/indoor-marijuana-growing/524910-10-14-vs-12-12-a.html here, justmeagain agrees with the "less light, less bud" theory: During flowering the plant still uses light, reduceing the light reduces the bud http://forum.grasscity.com/indoor-marijuana-growing/650011-12-12-11-13-10-14-help.html here, they get into a bit of a debate, but no real evidence is presented... http://forum.grasscity.com/indoor-marijuana-growing/508968-12-12-14-10-a.html it's hard to find good true side-by-sides here's an interesting one... http://forum.grasscity.com/advanced-growing-techniques/1019174-6-9-hrs-12-hrs-off-flowering-4.html the topic creator got banned.......anyways, he says: deep buddy Banned Join Date: Jun 2011 Posts: 96 \t and i will estimate at least acceptable mauturity and a 30-40% reduction in yield from what i would normally expect. i believe he did 10on/14off, so again, that DOES agree with the "less light, less bud" theory loki7 makes an awesome point in that thread: Pr and Pfr react to light, once you've got a decent amount of bud mass, the Pr stays Pr and doesn't turn back into Pfr... or atleast it doesn't turn back as fast. Have you ever re-vegged a flowering plant? A plant in heavy flower will take 2-3 weeks to start vegging again or longer because Pr doesn't turn into Pfr as quickly. and i had actually already "liked" that part of his post and other posts in that thread....sad that the topic creator of it had to flake out i don't think that's the one i mentioned in my original post though.... anyways, what loki7 was trying to convey was that EXTRA light past 12 hours can actually be a good thing, just as long as you don't go back into veg again, agreeing with the "less light, less bud" and conversely, "more light, more bud (as long as you don't reveg)"
yea ive seen alot of those oddball times people do, seems like it would be easy to make a mistake and turn your whole garden herme. im thinking more along the lines, of daylight savings timing is coming next month. im thinking about instead of losing an hour and having my lights come on an hour earlierfor the next 6 months (a few hours before i wake up), im just going to turn my timers "light out" function ahead 15 minutes one increment every other week. my plants are all in different stages so i gotta treat all my ladies the same. i figure a 15 minute extension of daylight every other week is gradual enough to not stress or herm the ladies, but i wasnt thinking about working my way up to 13 or nothing crazy. i just figure having my lights on from 8am-8pm id raise it 15 mins every few weeks to ease them into more time to soak in the rays, without making them think the season just started. i think anything over 13 hours would iffy. thing is, if giving flowering females actually LESS than 12 hours of light in a day, im not sure if it would work harder thinking the season is ending, or if they would just get less light/lumens. an hour a day adds up, im just trying to figure out if more daylight would be good, if they are indicas that wont herm, or if your actually going to get danker nugs by shortening the day 11/13. i would love to conduct this experiment, but i dont want to risk herming the few really mature ones.its like on one hand, you could be saving alot of energy by one less hour a day, but if every moment and ray of light counts, it seems it would be more beneficial to go the direction of 13/11. once i get my timers lined up for daylight savings time, im going to experiment with lengthening the day by 15 minute increments 2 weeks apart. but im not going past 12.5/10.5 ill pay close attention for any adverse or stressful reactions and i will update. *but think about it* outdoors cannabis generally always starts flowering in august. some finish later than others but in august the daylight is 13/11. it would make sense to keep shortening the days but thats only practical if your entire garden is in the exact same stage.