24/0 vs 20/4 light schedule?

[Barney86]

there's 2 camps on this one. the one that says the plants need a dark period and those who say they do fine without a dark period.

I've heard some say that 24/0 can cause hermies, but I use 24/0 for the first couple weeks of seedling with nothing bad happening yet.

I think the main thing i took away from my searching for this answer was that there's no difference and the 6 hours of dark saves energy costs was the main reason i use 18/6

Yup, first post in and thats exactly my thoughts on the matter. Never noticed any difference other than my leccy bill.
I do 24/0 for the first couple weeks then 19/5. Same with autos and some of mine get crazy big.
I dont care if the plant needs dark or if it doesnt tho really to be honest. My own logic says yes, perhaps the plant might grow a bit faster under 24/0 but if all the energy is going into growing the plant then surely the enrgy going into the roots must be taking the hit. At the end of the day were feeding a root system and not the actual plant so for that reason i choose 19/5.
Also my environment isnt really too controllable so i wouldnt get any benefit from that side of the argument.

 

[FelipeBlu]

what processes are you referring to?

Yes, please explain in terms of cannabis being a C3-type plant.

 

[StimpLedNoTill]

Yes, please explain in terms of cannabis being a C3-type plant.

Exactly, I'm hoping he can explain though..

 

[Carcass]

I'll take a shot at it...

95% of all plants are C3 type plants-that being said, C3 plants have a light cycle (light dependent)
and a dark cycle (light independent) during the light cycle the plants store up the energy created during photosynthesis,and during the dark cycle,they convert that energy,combined with Co2 into carbohydrates that the plant can use for growth.
C3 plants will have a "dark cycle" with or without the presence of light (light independent)
It needs this to produce the chemicals it needs to live

In other words,even if the lights are on for 24 hours,the plant is still going to have its own "dark cycle"which it uses for this conversion process .

 

[Remystemple]

I'll take a shot at it...

95% of all plants are C3 type plants-that being said, C3 plants have a light cycle (light dependent)
and a dark cycle (light independent) during the light cycle the plants store up the energy created during photosynthesis,and during the dark cycle,they convert that energy,combined with Co2 into carbohydrates that the plant can use for growth.
C3 plants will have a "dark cycle" with or without the presence of light (light independent)
It needs this to produce the chemicals it needs to live

In other words,even if the lights are on for 24 hours,the plant is still going to have its own "dark cycle"which it uses for this conversion process .

That's super interesting. Now just wondering if the conversion process is more or less efficient with and without the dark period.

 

[Carcass]

Now just wondering if the conversion process is more or less efficient with and without the dark period.

That's where the differing methods/opinions come in - some think yes,some think no...
A side by side comparison or 2 would help answer that question once and for all...

 

[Remystemple]

That's where the differing methods/opinions come in - some think yes,some think no...
A side by side comparison or 2 would help answer that question once and for all...

For me the only reason i'd do 24 is if i didn't want to worry about night time temps and humidity. it'd be easy to set it and forget it with 24 on.

 

[FelipeBlu]

dark cycle (light independent)

Seems to imply that the plant doesn’t care.

 

[Carcass]

Yep-doesn't really matter what we do,the plant has certain chores to perform, and will do it's
work,whatever the light situation...sort of like "the show must go on"

 

[Remystemple]

Yep-doesn't really matter what we do,the plant has certain chores to perform, and will do it's
work,whatever the light situation...sort of like "the show must go on"

So now i'm thinking that what i've read about people shocking or hermying plants from it. maybe the light schedule had nothing to do with these instances. or maybe some strains don't like it.?
either way it's always a good topic lol.

 

[LiberalThinker]

In the day, plants make sugars and in the night, they use them.

That's where the differing methods/opinions come in - some think yes,some think no...
A side by side comparison or 2 would help answer that question once and for all...

Seems to imply that the plant doesn’t care.

Or, one is ignorant of the effects. Cannabis has evolved as a short-day plant, which means it flowers when the light drops below a certain period. Where cannabis evolved, the maximum day length is probably 13-14 hours. Has it been objectively demonstrated that 18+hours of light produces more weed? As an experiment, I've decided to try the Gas Lantern method, which uses a maximum of 13 hours light in 24 hours during veg.

 

[Remystemple]

In the day, plants make sugars and in the night, they use them.


Or, one is ignorant of the effects. Cannabis has evolved as a short-day plant, which means it flowers when the light drops below a certain period. Where cannabis evolved, the maximum day length is probably 13-14 hours. Has it been objectively demonstrated that 18+hours of light produces more weed? As an experiment, I've decided to try the Gas Lantern method, which uses a maximum of 13 hours light in 24 hours during veg.

That's crazy lol. I can't wait till i have a couple totes full of green, that's when i'll start trying stuff out. I plan to do a few side by sides eventually.

are you gonna journal this?

 

[FelipeBlu]

So now i'm thinking that what i've read about people shocking or hermying plants from it. maybe the light schedule had nothing to do with these instances. or maybe some strains don't like it.?
either way it's always a good topic lol.

This is different. During flowering, the plant can sense the presence of red light, and that can disrupt hormonal effects, and have unintended consequences.

 

[LiberalThinker]

I'll take a shot at it...

95% of all plants are C3 type plants-that being said, C3 plants have a light cycle (light dependent)
and a dark cycle (light independent) during the light cycle the plants store up the energy created during photosynthesis,and during the dark cycle,they convert that energy,combined with Co2 into carbohydrates that the plant can use for growth.
C3 plants will have a "dark cycle" with or without the presence of light (light independent)
It needs this to produce the chemicals it needs to live

In other words,even if the lights are on for 24 hours,the plant is still going to have its own "dark cycle"which it uses for this conversion process .

When it goes into a dark cycle during daylight hours, are those daylight hours being wasted? I wonder.

That's crazy lol. I can't wait till i have a couple totes full of green, that's when i'll start trying stuff out. I plan to do a few side by sides eventually.

are you gonna journal this?

I might do in a week or two if looks like handling it. I slipped it into a 13 routine last night after an 18/6 hour day. So far, up to now, it's had a 12 hour dark period, interrupted for an hour with light in the middle of it, and is now just finishing a 12 hour day. It's nearly done a full cycle. It's only just starting its second proper set. The change, I hope, shouldn't upset it too much at this stage. This is going to be a 4-way-gas-lantern-scrog. Should be fun.

 

[LiberalThinker]

Yup, first post in and thats exactly my thoughts on the matter. Never noticed any difference other than my leccy bill.
I do 24/0 for the first couple weeks then 19/5. Same with autos and some of mine get crazy big.
I dont care if the plant needs dark or if it doesnt tho really to be honest. My own logic says yes, perhaps the plant might grow a bit faster under 24/0 but if all the energy is going into growing the plant then surely the enrgy going into the roots must be taking the hit. At the end of the day were feeding a root system and not the actual plant so for that reason i choose 19/5.
Also my environment isnt really too controllable so i wouldnt get any benefit from that side of the argument.

This is my main motivation for trying the 12+1 method and I hypothesize this is more important than is generally recognized. Also, if I can get the same or better results with less electric used I'll be happy.

 

[Remystemple]

This is my main motivation for trying the 12+1 method and I hypothesize this is more important than is generally recognized. Also, if I can get the same or better results with less electric used I'll be happy.

you also have to wonder if the transition to flower will be faster.

 

[LiberalThinker]

you also have to wonder if the transition to flower will be faster.

Yes, that's a possibility because it's only an hour away from flowering, once that interrupting hour is removed. The flowering hormones may already be primed more than on 18/6.

 

[DaddyKush]

i like sleeeeeep, i feel like most living things need sleep too Zzz

I've heard from so many reliable sources that plants do benefit from some dark time, and at the same time there are no discernible benefits to 24/0 that I've ever seen. Plus, isn't it nice to give your equipment some time to cool down every day? That's important too.

 

[Dogwash]

Has anyone found a difference between 24/0 veg, 20/4 and 18/6? While vegging, cannabis doesn't require a dark period so is it just slower growth and better on the electric bill to give a dark period? Would also help with temps depending on grow environment. All input is always appreciated!

I'm 6/2 all the way in veg

Stops heat build up, allows plants more frequent dark periods

 

[BTzGrow]

I agree with @FelipeBlu and others regarding DLI. I have grown using 24/0 schedule start to finish with an Auto and felt there was no adverse effects. So during Veg Cycle 24/0 is just fine.

The only caveat is there is not as much need to use the electricity and exceed a DLI of 25 or so for Veg Cycle. The other side to that is in flowering the plant needs a higher DLI over 35ish. I'm like a hawk on power consumption. So if I can drop the lights down to achieve the appropriate DLI sooner, I'll turn off the lights and save on the power bill.