Staggering down the light cycle to 12/12

[growdaddy69]

I use the week of transition as exactly that and decrease the light an hour a day from 18/6 to 12/12
Now whether it makes any difference to the quality of the grow, I can't say.
But it does satisfy my itch to be as anal as possible with my grow

That's the most natural way to do it which mimics the way it's done in nature.

 

[Indicolas]

Just did a direct flip to 12/12 and I swear I already see stigmas from overnight. Like they were just waiting. Eventually they show regardless.

 

[SmokingWings]

That's the most natural way to do it which mimics the way it's done in nature.

Nature does it by shortening the length of usable sunlight by about 90 seconds a day.

The thing about humans is we try to learn, mimic and then grow better than nature does.

 

[SmokingWings]

Just did a direct flip to 12/12 and I swear I already see stigmas from overnight. Like they were just waiting. Eventually they show regardless.

Going from the vegetating light schedule directly to the flowering schedule makes the most sense. Avoiding the constant change in the lights is one less chore.

As you mention, it does seem like the buds suddenly start pushing out stigma/pistils overnight but most of the time it seems to be within 5 days of the switch over.

 

[Slapalottapuss]

Totally unnecessary imo. Just slam them to 12/12. Otherwise it’s just a wasted of time, nutrients etc.

 

[growdaddy69]

Totally unnecessary imo. Just slam them to 12/12. Otherwise it’s just a wasted of time, nutrients etc.

I just studied 2 weeks getting ready to make the "flip" and after all the study, reading, observing, seemed the best thing was to just slam them into 12/12. I have 3 autos and 2 photos in a 2x4x6, VisparSpectra P2500. Started June 11, autos finishing (1 chop, 2 ready in 3-9 days), and flipped to 12/12 flower mode( Sept 1) for the photos so they will finish in the next 8 weeks +-. All plants germinated June 11.

 

[Smokey0418]

G'day all, hope you are well.

I planning my next grow and have been considering the 2 different ideas when flipping the light to flower.

1) going from 18/6 to 12/12 over the course of a week i.e. Sunday 18hrs, Monday 17hrs, Tuesday 16hrs, Wed 15hrs and so on until I reach 12on 12off.

2) complete darkness for 24-36hrs, then straight to 12on 12off.

Interested in hearing about peoples experiences with trying these 2 methods of flipping the light cycle.

I watch another friend that does this religiously.
He would reduce an hour every four days.
Day twenty flower begins 12/12.

It’s a reduce stress thing.

 

[Delps8]

Cannabis is a C3 plant so it can grown using a 24 hour photo period.

If you're giving your cannabis plant < 24 hours of light, you're reducing the plants' ability to generate food (photosynthesis). As a result, you're reducing crop quality and yield.

 

[Slapalottapuss]

Cannabis is a C3 plant so it can grown using a 24 hour photo period.

If you're giving your cannabis plant < 24 hours of light, you're reducing the plants' ability to generate food (photosynthesis). As a result, you're reducing crop quality and yield.

I’d humbly disagree with that. The dark period is absolutely necessary. Plants store excess energy, move it to the root section and rest during the dark period. 24 hours of light during veg will not increase anything except electricity consumption rates. The best auto growers out there run 20/4

 

[SmokingWings]

I’d humbly disagree with that. The dark period is absolutely necessary. Plants store excess energy, move it to the root section and rest during the dark period. 24 hours of light during veg will not increase anything except electricity consumption rates. The best auto growers out there run 20/4

That is what I thought for years, and more years. Then there were people here who would go the extra step and explain why Cannabis would grow better under a longer sunlight or 'electrical lights on' schedule. The research was there and the Marijuana/Cannabis belonged to a type of plant that did better than the usual plants that humans have cultivated for120 or so centuries.

It was a bit of a shock since I had learned plants required a period when photosynthesis dropped to zero and another entire process began. But I kept running into references that supported the concept that Cannabis was a class of plant that did not require the "resting or dark period" when photosynthesis would drop to zero.

So why the better growers running 20/4? If I am remembering right many of the experimenters were coming back with results that showed that their Cannabis plants did just almost as well under 20/4 as they did under 24/0.

 

[Delps8]

I’d humbly disagree with that.

There's nothing humble about what you've said. The striking characteristic of what you've written is that what you've written is either incorrect or meaningless.

The dark period is absolutely necessary. Plants store excess energy, move it to the root section and rest during the dark period.

Cannabis is a C3 plant and is categorized as such because it does not need "a dark cycle" for its Calvin cycle to run.

Plants do not store excess energy. Photons + CO2 -> C6H12O6 + O2. The cells in the plant get the glucose and the O2 is emitted into the atmosphere.

You might want to brush up on your plant bio.

24 hours of light during veg will not increase anything except electricity consumption rates.

Is that re. 24/0 vs 18/6?

If so, please cite the research.

I ask because, I've read a few books on growing cannabis and have read at least dozens of research papers on how cannabis reacts to grow lights but nothing in the hundreds and hundreds of hours I've spent studying cannabis could possibly support your assertion.

The best auto growers out there run 20/4

"the best auto growers…" -

That's statement may be referred to an "appeal to authority" and is considered meaningless in argumentation.

I've been a member of a cannabis site that's dedicated to auto flowers for > 2 years now and a my observation has been that a variety of photoperiods are used for autos. I haven't done any surveys, granted, but that's the sense that I get from the hundreds of pages of grow journals that I've read there.

I use 24/0 in seedling and most of veg, then 20/4, 18/6, 21.3, etc. in flower. I change the photoperiod in flower as a means of changing DLI.

Why not use the dimmer? Most of the equipment in my tent is controlled digitally but I can't dim my lights because I use Growcraft lights and their 330 watt driver can't be controlled digitally. With that limitation, I'll change the light schedule by an hour or two to get the DLI I want. That approach is much easier than going into the tent, getting out the light meter or PAR meter, and fiddling with the dimmer.

Overall, I'm pleased with my results. While I'm not concerned about being a "best grower", anything less than a 1 pound grow from my 2' x 4' tent is a failure and my yields are consistently 18 to 22 ounces.

If people are interested, check the grows in my sig block. The latest one was a photo, the others were autos. I take light readings (Apogee MQ-500) (almost) daily, using at least a dozen sample points, and publish them in my journal.

 

[Slapalottapuss]

my only reason for saying the better auto growers are using 20 is due to seeing a few guys pull monsters from DWC at 20/4. I’ve spoke to more than a few and they say 20 is optimal.

I don’t grow auto so 24 would not ever work for me. Just going by what I have seen and read. I don’t know one single person that runs 24 on for anything. It’s just not necessary or worth the extra money. The plants can only use so much light. The rest goes to waste. If running 24 on one would have to lower their light intensity to make the extra hours of light useable.
If 24 on made that much difference every one would do it and light Dep wouldn’t exist.

So I will run 18 on during veg with my photos. I’ve run them at 15-24 hours in and have had the best results with 18/6.

Just because they can take it doesn’t mean they should. I’ll pull 3+ pounds out of a 3x3 tent with 750w available power. All lighting is adjusted to maximum DLI for each stage.

 

[Delps8]

So why the better growers running 20/4? If I am remembering right many of the experimenters were coming back with results that showed that their Cannabis plants did just almost as well under 20/4 as they did under 24/0.

"better growers" - that leaves me out….

"experiments" - got data?

I use 24/0 under "mid-veg" (whenever that is!) and then drop to 20/4 but will also use 18/6, 19/5, or whatever photoperiod I need to get to the desired DLI.

 

[Slapalottapuss]

lol. If you want to run 24 hours of light go right ahead. Im saying I disagree with the fact that because they “can” means they should. Enjoy your day sir. Why even ask?

 

[Slapalottapuss]

"better growers" - that leaves me out….

"experiments" - got data?

I use 24/0 under "mid-veg" (whenever that is!) and then drop to 20/4 but will also use 18/6, 19/5, or whatever photoperiod I need to get to the desired DLI.

SMH. You said it right there. DLI is a measurement of useable light for a certain time period. If I understand you correctly you are dimming your lights to get the same amount of useable Photons in 24 hours that you could get in 18?

 

[Delps8]

my only reason for saying the better auto growers are using 20 is due to seeing a few guys pull monsters from DWC at 20/4. I’ve spoke to more than a few and they say 20 is optimal.

"a few guys" - got it.

I don’t grow auto so 24 would not ever work for me. Just going by what I have seen and read. I don’t know one single person that runs 24 on for anything.

24/0 seed to weed is not uncommon for autos and many growers here use it in veg.

It’s just not necessary or worth the extra money.

You state this as a fact without knowing the cost of electricity and without knowing the value of the crop.

The plants can only use so much light. The rest goes to waste. If running 24 on one would have to lower their light intensity to make the extra hours of light useable.
If 24 on made that much difference every one would do it and light Dep wouldn’t exist.

So I will run 18 on during veg with my photos. I’ve run them at 15-24 hours in and have had the best results with 18/6.

Just because they can take it doesn’t mean they should. I’ll pull 3+ pounds out of a 3x3 tent with 750w available power. All lighting is adjusted to maximum DLI for each stage.

3 pounds from 3' x 3' - incredible!

Most seed sellers estimate 400-600± gm/M2. I had one harvest that was 880, IIRC but your 3 pounds from 9 ft2 is 1360 gm from 0.84 m2 = 1619 gm/m2. That's about three times the number from seed vendors!

How did you cram 750 watts into a 3' x 3'? I had 500 watts on one grow but that was with three lights, one of which was in front of the tent, aimed at the "front row".

 

[Slapalottapuss]

Enjoy your day sir. Run on 24 I don’t care but I will never believe that it is necessary for yield.

ETA I build my own light fixtures. 3 drivers, supplemental UVB, IR & far red. All independently controlled. Total canopy cover and maximum penetration. don’t know what to tell you but sometimes the data doesn’t necessarily match the outcome.

 

[Delps8]

How much more are you pulling at 24 hours?

I'm not "at 24 hours".

I use 24/0 in seedling + part of veg, then switch to 20/4'ish.

 

[Slapalottapuss]

Noted.

 

[Delps8]

SMH. You said it right there. DLI is a measurement of useable light for a certain time period. If I understand you correctly you are dimming your lights to get the same amount of useable Photons in 24 hours that you could get in 18?

No.

You're still stuck on 18/6. There's nothing magic about 18/6 vs 19/5 vs 18.999/5.001.

As you've said, it's DLI. Poke one of the links in my sig block and scroll through for light info.

This is from my Spring 22 grow. It's just DLI. I don't put my lighting schedule in my daily light summary. :-(

Net, net - in flower, I'll change lights out to change DLI. I'd guess I do that maybe a couple of times a week. It makes no difference to the plant that lights are out "an hour early" or "an hour later". That's autos, of course. Do that with a photo and, yeh, things don't work out too well.


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