Is there an answer for perfect light cycle from the start to the end?

GrownAtHighAltitude said:

This thread is a mess.

I switched to 12/1 and 8/16 years ago and never looked back.

12 on, 5.5 off, 1 on, 5.5 off - veg
8 on, 16 off - bloom

It took me awhile to understand the differences but I won't go back now. It's easier to transplant outside from the indoor veg schedule also because it's similar to lantern lighting technique. I find that unworthy males tend to show flowers under 12/1 which helps in separating plants early. Good, solid males (and females) will only grow leaves until after flip.

Much less electricity usage and better plants IMO. Added bonus that my plants aren't as stressed out as they were with 24/0 veg. (18/6 was better than 24 for this reason also)

Cannabis only needs 8 hours of sunlight per day and then it has enough fuel for the day. The dark rest gives the rhizosphere a chance to recover.

I grow organic and likely hydro growers won't care about this.

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I grow organic only too. But i've never heard about such light schedules in my life no matter how much i've read about them. Everyone gives different advice so it's even harder to change the standard 18/6 to 12/12 schedule without real data. Would have to test it all myself since there's no real data available where professional growers (or someone really advanced home grower) tests the same plants in the same conditions with different schedules to see how it affects the grow and end results.

But who is ready to start such a test that requires money and space if you really want to test multiple schedules at the same time and make sure the conditions are the same for every space/plant?

Like i've said i don't believe that massive growers haven't tested this in their own space to maximize their growth, quality and save as much money they can when their massive rooms and lights above the plants require so much money to even run, so why wouldn't they make sure to save as much money they can meanwhile maximizing their growth, when they can easily test this with their space? Everyone can ask this from themselves and get an answer that is pretty obvious.

When i look all those inside growing plants in video tours, they're so damn massive and almost everything is automatic. And i've seen their own labs which are massive too, so why wouldn't they test such simple stuff on their own? I'm 100% sure it has been done, BUT not made public to get an edge in the growing industry, too bad.

And i'm aware other conditions affect the "perfect" light schedule too, only if we had all that data available suddenly, i'm sure EVERYONE would start following them and act like yeah that was my preference all a long

I strained my eyes rolling them so hard.

Blossom21 said:

I grow organic only too. But i've never heard about such light schedules in my life no matter how much i've read about them. Everyone gives different advice so it's even harder to change the standard 18/6 to 12/12 schedule without real data. Would have to test it all myself since there's no real data

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I was skeptical at first but I'm glad I switched.

I got the info from Joe Pietri originally. I don't like most of his other advice (I've read his two books), nor his attitude about other growers, and his seeds are way overpriced, but his lighting advice is spot on and works great.


It's a 30% / 40% reduction in electricity costs and less stress on the plants.

Blossom21 said:

And this has been proven with multiple lab tests with same conditions? I'd like to see sources for this.

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You really could have saved yourself all of this headache if you even tried to look into it.
I’m not sure how you’ve made it this far asking such a simple question and getting no proper responses.

Since I see you’re someone who likes data and facts, jump down the Dr. Bruce Bugbee rabbit-hole.

He is the inventor of the PPFD/PAR meter, does research on growing plants for NASA and is a fucking absolute lighting NERD and I live for it. There is nobody as educated as him in lighting and I will die on this hill. Also, this whole industry secret thing, that’s not a real thing. We don’t hide anything. A lot of us are people who started at home and still use many of the same techniques.

___disillusion said:

You really could have saved yourself all of this headache if you even tried to look into it.
I’m not sure how you’ve made it this far asking such a simple question and getting no proper responses.

Since I see you’re someone who likes data and facts, jump down the Dr. Bruce Bugbee rabbit-hole.

He is the inventor of the PPFD/PAR meter, does research on growing plants for NASA and is a fucking absolute lighting NERD and I live for it. There is nobody as educated as him in lighting and I will die on this hill. Also, this whole industry secret thing, that’s not a real thing. We don’t hide anything. A lot of us are people who started at home and still use many of the same techniques.

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As smart as he is, I've never heard him talk about alternative lighting schedules such that can save 30-40% on electricity costs...

GrownAtHighAltitude said:

As smart as he is, I've never heard him talk about alternative lighting schedules such that can save 30-40% on electricity costs...

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I remember you doing unusual hours but I can't remember what they are?

Savings of 30/40% are always welcome I might give it a try.

Sure crank up your lights 30% so that you can cut back your lights on time by that same 30%. DLI is the same either way, and so are the electrical costs. Chasing your tail there IMO.

PJ Diaz said:

Sure crank up your lights 30% so that you can cut back your lights on time by that same 30%. DLI is the same either way, and so are the electrical costs. Chasing your tail there IMO.

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I thought the 30/40% saving was the same lighting/wattage but less hours of running it?

Our electricity prices are set to rise again for the 2nd time this year a total of 50% increase.

Star Dog said:

I thought the 30/40% saving was the same lighting/wattage but less hours of running it?

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I have no idea, but you can't game DLI. If a grower is having success by cutting their lights on time back by 30%, then I'd bet money that they would have the same success by just dimming their lights 30%. Having plants in the dark 16 hours a day isn't a great idea IMO.

PJ Diaz said:

I have no idea, but you can't game DLI. If a grower is having success by cutting their lights on time back by 30%, then I'd bet money that they would have the same success by just dimming their lights 30%. Having plants in the dark 16 hours a day isn't a great idea IMO.

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My buds are as good as they ever were going back 20 years of growing.

Cannabis doesn't need more than 8 hours. Anything else is a waste.

12 on, 5.5 off, 1 on, 5.5 off. That sets the plant up to run on less light overall.

Plants on 18/24 veg end up being light junkies and they will definitely require 12/12 to flower properly.

If they get used to less light in veg, but enough to stop the flowering hormones from being produced, they only need 8 in flower and their tanks are full.

I was skeptical too but 3 years later and I am not switching back.

GrownAtHighAltitude said:

My buds are as good as they ever were going back 20 years of growing.

Cannabis doesn't need more than 8 hours. Anything else is a waste.

12 on, 5.5 off, 1 on, 5.5 off. That sets the plant up to run on less light overall.

Plants on 18/24 veg end up being light junkies and they will definitely require 12/12 to flower properly.

If they get used to less light in veg, but enough to stop the flowering hormones from being produced, they only need 8 in flower and their tanks are full.

I was skeptical too but 3 years later and I am not switching back.

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Do you have a seed to harvest journal I can check out?

3 months veg under 12/1



Indoors under 8/16 315 CMH

Shoreline x Deadhead OG


Girl Scout Haze Cookies

bk78 said:

Do you have a seed to harvest journal I can check out?

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I need to do that. Also a side by side. I need more space indoors...

GrownAtHighAltitude said:

My buds are as good as they ever were going back 20 years of growing.

Cannabis doesn't need more than 8 hours. Anything else is a waste.

12 on, 5.5 off, 1 on, 5.5 off. That sets the plant up to run on less light overall.

Plants on 18/24 veg end up being light junkies and they will definitely require 12/12 to flower properly.

If they get used to less light in veg, but enough to stop the flowering hormones from being produced, they only need 8 in flower and their tanks are full.

I was skeptical too but 3 years later and I am not switching back.

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LMFAO, "Plants on 18/24 veg end up being light junkies", priceless. That's seriously the most ridiculous thing I've ever read on this forum.

"Light junkies", LOL.

You seem to be missing the point, that it's not the amount of time per day that matters as much as it is the DLI.

Let's see your evidence.

GrownAtHighAltitude said:

3 months veg under 12/1

View attachment 5154831

Indoors under 8/16 315 CMH

Shoreline x Deadhead OG
View attachment 5154832

Girl Scout Haze Cookies

View attachment 5154833

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They don't look great, I'll be honest.

PJ Diaz said:

They don't look great, I'll be honest.

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Well, I am happy, and I get no complaints. I grow in soil only, no water, and I have plenty of interest.

I also pay 30/40% less for electricity. I like the math, but you do you. These are just the pics I have on my phone right now. I have posted plenty of others.

I am enjoying the roadkill skunk in the Shoreline OG cut too but nobody believes me about that either because "RKS is dead" and "it doesn't look good".

I got nothing to prove to you or anyone else.

Those flower pics are at 63 days for strains that normally go 70. I have noticed that this light schedule seems to come with the benefit of faster finishing. I have witnessed it myself. The link I just posted also suggests the same.

Blossom21 said:

I tried to talk about this topic with people who don't just give just their own preference and leave, BUT actual done testing with data. But never got real results, just people talking how their preference is the best

One thing i'm sure is that the bigger cannabis growers (at least) have tested this to maximize their grow with automacially adjusting leds (and adjusting everyhing to pretty much perfection). But would they wanna share their results to everyone? I'm pretty sure not. Unless someone in the industry leaks it.

Of course this could be tested in multiple identical grow rooms, but that would require time, money and patience that i know most people wouldn't wanna do because their own preference works from the typical 18/24-24h for photoperios and autos, then at the veg bring down their lights for photoperiods at least.

I've alwatys grown with the old 18/6 cycle photoperiods and they turn fine, but is there a faster method proven? Would giving more light in any stage give bigger results? So the answer for this would be nice to be for photoperiods, i don't can about autos.

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Good question, its a good way of looking at things an can help you fine tune things. But the answer would really depend on what your growing. For example heavy sativas (meaning real heavy sativas an not what some of the comercial industry portray as being sativa) an tropical landraces most can be started on 13 on an 11 off or even 12 on-12 off as they have adapted over time to veg either untill a geneticly set size or untill the dark hours are slightly bigger than the light hours before flowering. Most once flowering is triggered will still continue to veg simultaneously till they reach the size they feel is needed depending on root size, conditions and space around them. Personally though i found flowering heavy sativa/tropicals beter an stlighly faster at 10 on- 14 off. I found this to give a stronger flowering respose with less issues of scraggly reflowering/almost reveging type growth, an gave a more overall compact looking flower.

Iv noticed a lot of heavy indicas can be bloomed on 14 on- 10 off an the yields do increase however the flower time is slightly lenghthned. Though personaly to balance the cost vs yield i most of the time used to flower the more indoor friendly/more indica type plants on 13 on- 11 off. Which used to only increase flower time by a few days but used to up my yields enough so it would be worth the extra cost.