has anyone tried an 18/12 light cycle?

lvstealth · Mar 30, 2021

would it help/hurt to run an 18/12 light cycle during flower? would the plant "think" the days were 30 hours long and therefore take more actual days to finish? would the extra light hours help? would it still flower? i understand it has to have 12 hours of night uninterrupted, but does it necessarily need only 12 of light? i am just curious about how it works, and how much one could manipulate things.

has anyone here tried it?

mysticepipedon · Mar 30, 2021

I'm betting someone has tried it, though I've never heard of it.

This is what we know the plant will do: It will create flowering hormones and then not create them again for more than a day, then create them again.

My guess would be that this won't work for a successful grow. The plants will be facing a situation they never faced in their millions of years of evolution. Most cannabis plants will say to themselves, "This shit is fucked up! I'm making both male and female flowers."

growsince79 · Mar 30, 2021

I was gonna try but I don't have a 30 hour timer lol. What does work with most plants is 13 light-11 dark- makes for bigger buds.

lvstealth · Mar 30, 2021

ive seen stories about it, most say it worked for them, some even try to explain it!

many have the same timer issue, but with the smart plugs that is a bit easier now.

i was looking around because someone said the next challenge they would like to do is a pound under 200w, and i thought if you gave it longer daylight it might make up for lesser watts light... but mostly all that just confused me! there are no real studies with real data, but lots of people trying different lighting schedules and most "work" to some extent, some even get high prase! lol. but you know google... it led me deeper into the "what a plant actually needs" and what it tolerates. they are quite remarkable in their willingness to grow!

the theory is they need the 12 hours dark to make the hormones they need to flower, but the light period can be whatever - their needs not truly established.

they grow in places that dont get any dark to places that get very little light, so i would guess they start out pretty flexible just wanting to grow.

i would think it is above my level of husbandry. if i live long enough i want to experiment with things like this. but for now, i just want a first grow!

DavidMykel · Jul 26, 2021

lvstealth said:
would it help/hurt to run an 18/12 light cycle during flower? would the plant "think" the days were 30 hours long and therefore take more actual days to finish? would the extra light hours help? would it still flower? i understand it has to have 12 hours of night uninterrupted, but does it necessarily need only 12 of light? i am just curious about how it works, and how much one could manipulate things.

has anyone here tried it?

Photoperiod plants need 12/12 to start flowering, im running 12/12 from seedling but at the 4 or 5 week mark when it starts to bud im gonna switch it 18/6 for 3 weeks to increase bud size

Aqua Man · Jul 26, 2021

Dark light cycle in photos is a tug of war I think they may reveg under thise conditions.

Ponky · Jul 26, 2021

The research has been done. Every weird combo under the sun. The wheel is still better. 12/12. Unless you're a literal landrace geneticist.

Aqua Man · Jul 26, 2021

Here is a pretty good explanation of the tug of war. Cannabis are short day plants.

Florigen - Wikipedia

en.m.wikipedia.org

freezeland2 · Jul 26, 2021

growsince79 said:
I was gonna try but I don't have a 30 hour timer lol. What does work with most plants is 13 light-11 dark- makes for bigger buds.

I was wondering the same thing about a timer that would support such a thing without being manually set each day. What a PITA.

Aqua Man · Jul 26, 2021

freezeland2 said:
I was wondering the same thing about a timer that would support such a thing without being manually set each day. What a PITA.

Amazon.ca

freezeland2 · Jul 26, 2021

Aqua Man said:
Amazon.ca

What will they think of next, lol. I’m an old fart. Still using my hydro farm 24hr timers after 20 years of service.

Aqua Man · Jul 26, 2021

freezeland2 said:
What will they think of next, lol. I’m an old fart. Still using my hydro farm 24hr timers after 20 years of service.

Yeah I did the timers with the pegs... they give me nightmares

Habosabin · Jul 26, 2021

I just read another thread. An article was saying 24/12 will work. I'm out the door or else I would link it.

Habosabin · Jul 26, 2021

Here it is. It has an article on 24/12.

24/12 day night cycle shortens flowering time?

So I had a thought about flowering. Since cannabis gets its direction from the night cycle, you could theoretically cut 6.5 days for every 30 off of your flowering time. Cutting an 8 week flowering time to 6 weeks and a day. If your day and night cycle was 24-12 the plant would still see the...

www.thcfarmer.com

freezeland2 · Jul 26, 2021

Aqua Man said:
Yeah I did the timers with the pegs... they give me nightmares

In 20 years I have never had a failure with one. Set it and forget it. If it ain’t broke I ain’t fixing it.

Aqua Man · Jul 26, 2021

Habosabin said:
Here it is. It has an article on 24/12.

24/12 day night cycle shortens flowering time?

So I had a thought about flowering. Since cannabis gets its direction from the night cycle, you could theoretically cut 6.5 days for every 30 off of your flowering time. Cutting an 8 week flowering time to 6 weeks and a day. If your day and night cycle was 24-12 the plant would still see the...

www.thcfarmer.com

Ok here's the issue that's not being considered.... if you are maximizing the DLI then there is no difference in photons received. And plants perform important and different functions in light and dark.

Plants have a saturation rate and a saturation level. I can tell you right now if you put a plant under the ideal intensity we use to flower under 12/12 and put it on for 18hrs your going to damage the plants.... never mind 24 or 48hrs. You would effectively need to reduce the light intensity proportionately if you notice the intensity is not discussed here.

To me it makes no sense to extend the light cycle of you have the lighting to provide the intensity to maximize photosynthesis.

This guy is a quack and a trying to get his 15 mon of fame from a ridiculous point of view that leaves out crucial information because it would destroy his claims.

It's all about the DLI. The amount of photons given over a light cycle. Not the length of the light cycle. This is why plant get about 1/3 more light intensity when switching from 18/6 to 12/12. So they can continue to maximize the photons given in a light cycle. This is also why autos can be grown under a lower intensity light because ether have an extended light cycle.

Sorry but I call this absolute nonsense and a gimmick. That clown either has false credentials or is a scammer.

Aqua Man · Jul 26, 2021

So basically the plant captures photons the more intense the light the more photons. Photons are converted by the plant into.... we will call it energy. This is called photosynthesis. The higher the intensity the higher the photosynthetic rates. At the point a plant cannot keep up with the rate of photosynthesis over a time period is called photosaturation. As you get closer to photosaturation photosynthesis become less efficient and can actually start reversing some actions. The highest photosynthetic rates are the first several hours of lights on.

The dark period allows the plant to process and use the manufactured energy including extras out through the roots to feed microbes in the media. Now this process happens all the time but much more efficient in the dark cycle. Think of it like the plant has so much space to store energy and if it being produced faster than moved and used eventually it backs up. This goes to my point of if your making say 100,000 units in 12 hrs then mass moving and clearing out. Or you make them slower over 24 hrs then clear then out. The only difference is that some are being used all the time but in order to do it over 24hrs you need to slow production.

This is why you have seen many experiment with light cycles ober the years of say 6on 6 off... tobtry to retake advantage of the higher photosynthetic rates early on in the light cycle. But there is a flaw with that too which may actually be plausible in the near future. The plant takes time to change processes and now we are learning that manipulating the far red spectrum just before lights on and off change speed up this change in process greatly.

Habosabin · Jul 26, 2021

They are saying the bud will mature more quickly using this? Is it because it just receives more DLI in 7 days versus the 12 hour? What makes buds mature? This implies is all photons.

Aqua Man · Jul 26, 2021

Habosabin said:
They are saying the bud will mature more quickly using this? Is it because it just receives more DLI in 7 days versus the 12 hour? What makes buds mature? This implies is all photons.

Honestly I can say it does nor can I explain why it would but I can say I highly doubt the claims made or atleast for the reasons given. I'll have to actually read and not skin to see if I can validate that portion. But I feel if it does it will come at the cost of yield.

PipeCarver · Sep 2, 2021

Aqua Man said:
Honestly I can say it does nor can I explain why it would but I can say I highly doubt the claims made or atleast for the reasons given. I'll have to actually read and not skin to see if I can validate that portion. But I feel if it does it will come at the cost of yield.

I've just switched some auto's I've had on 12/12 for about 7 weeks to 18/6. I was told that it would help boost under performing photo's in the last 7 - 10 days of flower. Not sure about with auto's but I guess I'll find out. Doing this allows me to move all my vegging plants under the 1000w hps for the week as I take cuttings off them and extend my veg period. It also frees up space in my veg room Win Win lol.

has anyone tried an 18/12 light cycle?

has anyone tried an 18/12 light cycle?

lvstealth

mysticepipedon

growsince79

lvstealth

DavidMykel

Aqua Man

Ponky

Aqua Man

Florigen - Wikipedia

freezeland2

Aqua Man

freezeland2

Aqua Man

Habosabin

Habosabin

24/12 day night cycle shortens flowering time?

freezeland2

Aqua Man

24/12 day night cycle shortens flowering time?

Aqua Man

Habosabin

Aqua Man

PipeCarver

Privacy & Transparency

Privacy & Transparency