The minimum light needed to prevent flowering

[No3odiesShad0w]

I'm curious. If 12 hours of light or 12 hours of darkness will trigger a photoperiod plant to go into flower. What's the minimum amount of light you need to prevent the plant from flowering? 14hrs? I know 16hrs for sure will prevent most photoperiod plants from flowering. I also know some plants that are more sensitive will also be triggered by 13 hours of light and 11 hours of dark.

The rain I want to know it's because I want to keep that UG seedling as a mother for a bit. Since I'm growing autos, I can keep the lights on longer but I also don't want to keep them on more hours than I need to for sale of my electric bill. Running the window ACs is using 7kwh or more a day. Now multiply that by 2 plus everything else running in this place. The bill is really high in the summer.

I said I wasn't going to grow this summer for this exact reason but I couldn't resist. Besides, that Mac 1 and pineapple Express are all but gone. I have maybe a quarter left of each. If I hadn't done this grow I would be hurting.

Right now I'm running the lights at 14hrs. Is that enough to prevent flowering for a mother plant?? Should I bump it up to 15hrs to be safe? Only problem then is my DLI will be high for the plants in bloom and the lights are at max height.
Thanks in advance 👍

[Allenpro]

I think it depends on the genetics and probably a bunch of other things, Inside I have switched from 12/12 to 14 on and 10 off and they revegged. Outside where I live in Maine but they will go into flower a couple weeks after the summer solstice and by the time the days get to 12/12 frost is highly likely so you hope they are done by then

[No3odiesShad0w]

Yeah I noticed that. My dad's plant started to flower shortly after the solstice. She's not blooming mad yet but there's are small flowers forming. Thankfully around this area we have warm weather until November sometimes. Last year in December we still had hoodie weather.

[Ckbrew]

Use 12/1 lighting. 12 hours on, 5.5 hours off, 1 hour on, 5.5 hours off. It is the about 12 hour darkness period that triggers bloom. Keep that interrupted and they stay in veg.

[No3odiesShad0w]

Yeah for sure it's that dark that triggers them not the light.
Sadly, Can't do a weird schedule like that. I have plants in bloom I don't want to stress them. That's why I was wondering if 14hrs is enough this way they only have 10 hours of dark.... But even that is tricky. Again it depends on genetics.

Maybe I should just do 15hrs on and 9 off. It's only going to be until October just to get a few clones for a side by side comparison. No more anomalies. No more different genetics. I'm going to clone the UG and use it to test my soil mix with peat VS my mix with Coco VS nutrient pack from Earthbox. This way I can get a good comparison and see what soil mix I go forward with

[Ckbrew]

The times we wish there was another tent. It is a PITA but you could move the bloom plants out of the tent for the extra dark time. A lot of work...

[Bluey]

I'm using 90 to 125 PPFD on flowering clones and that appears to be sufficient to flip them back into veg., but only just. On a 20/4 cycle.

It's the length of uninterrupted dark period that matters, not the light period.

[No3odiesShad0w]

Yeah it's the dark period it needs. I'm gonna keep it at the 14 hours and see what happens. Worse case, I'll raise it to 15 or 16 hrs if I need to.

Doesn't seem like there a consensus on the answer. I asked in a few places and keep getting the same answer. Just give it 18hrs of light. Like I don't need it growing big. I'm gonna give it whatever PPFD it gets on the floor of the 2x4 tent. I just don't want it blooming on me because I noticed the outdoor plants have started to bloom ever so slightly. My dad's plant has flowers

[No3odiesShad0w]

I have all those Mac1 x Blue dream maybe I'll run an experiment to see how many hours triggers it. One will get 11 hours of dark, another 10hrs and I'll see what happens. Then I'll have a definitive answer, at least for cannabis.

[ZiroOne]

If i remember it correctly:

9 hours of continuous darkness is not safe to prevent flowering. Almost all genetics with 3 weeks more in transition period will eventually start to flower even with just 9 hours of continuous darkness. So don't try 10 hours of continuous darkness if you don't want your plant to flower. It doesn't work. They will go into flowering with 9 hours darkness but they don't flower correctly.

There is a scientific experiment report on researchgate.com. Go read it and let me know if i was wrong.

[Rwise]

I have plants that are flowing at 14/10s, wasn't expecting it but there it is.

[Bowhunterwoody]

Same here.

[No3odiesShad0w]

Good to know I'll def try 15+.

[No3odiesShad0w]

For now they're small so I could just pop them into my kitchen when the lights go out at 10:00 a.m.