Light cycles

HideousPenguinBoy

HideousPenguinBoy

Well-Known Member
I have a multithreaded question about cannabis' light/dark cycles.

The tried and true method is 12/12. In the past few years it's been more 11/13 around. We also have the idea that you could start 12/12 and slowly change to 9/15 over the course of growth. Then also we have 730nm sleep initiators to add to the mix. What does what?

I know some people have made experiments and some know the science behind plant sleep and also the hormone changes from initiating flowering. Please dump relevant info and data! Opinions are nice, but base them on facts we can look at!
 
Cletus clem

Cletus clem

Well-Known Member
The far red will depend on how u use it. 15 min after lights off but continuing with 12/12 is said to shorten ripening time, earlier harvest. The same technique only lengthening lights on, 13/11, 14/10, will give the plant more time for photosynthesis. I guess with potential better yields? In theory, plants take 2 hours to “fall asleep”, with the flower initiator, its said this happens much faster. Plants spend all day using photosynthesis to make sugars that will get put to use wile it sleeps. It becomes a matter of more time to make sugars or more time to put them to use. Or does it really matter?
 
Richard Drysift

Richard Drysift

Well-Known Member
Pardon my ignorance but..
What the fuck is a sleep initiator? Ambien?
I have been setting my flower room to 11.5/12.5 for years which helps many of the hybrids I run finish in 10 weeks or less. More hours of darkness speeds ripening somewhat to the detriment of lower yield. No earth shattering revelations there.
Over the years I have experimented with decreasing hours of light during late veg phase:
The suns natural cycle outdoors doesn't go 18/6 to 12/12 overnight. Light hours are gradually increased from the beginning of the year until the summer solstice and then darkness slowly increases through autumn and eventually back again to the shortest day on the winter solstice. For thousands of years humans marked these days to know when to plant crops and when to harvest them.
Under indoor artificial lighting we can easily control the light cycle but most growers only use 18/6 or 12/12 depending upon stage of growth. Some strains like sativa doms can stretch out quite a bit after "the flip" because these plants have evolved near the equator which has a lengthier growing season than the rest of the world. Growers have developed many new sativa/indica hybrids to help reduce flower times but the genetics are still influenced by evolution.
Gradually reducing the hours of light from 18/6 down to 14/10 can help reduce stretching which can also increase yield somewhat by growing tight intermodal and lateral branching. The spaces in between the buds produce zero usable end product but by reducing these spaces you increase the amount of potential bud sites thereby increasing yield.
It goes like this...Start at 18/6 and veg until they are of a decent size. Then reset timer to 17/7 for a week. Then 16/8 for another week. Continue to reduce the hours of light by 1 hour a week and by the time they reach 14/10 most strains will begin to throw pistils at this light cycle. Then to 12/12 or 11.5/12.5 or whatever bloom cycle you want to set a week later.
 
SSGrower

SSGrower

Well-Known Member
HideousPenguinBoy said:
I have a multithreaded question about cannabis' light/dark cycles.

The tried and true method is 12/12. In the past few years it's been more 11/13 around. We also have the idea that you could start 12/12 and slowly change to 9/15 over the course of growth. Then also we have 730nm sleep initiators to add to the mix. What does what?

I know some people have made experiments and some know the science behind plant sleep and also the hormone changes from initiating flowering. Please dump relevant info and data! Opinions are nice, but base them on facts we can look
Click to expand...
No scientific basis to do it, only curiosity. I use an arduino and by choosing a ratio >1 speeds time, < 1 slows it. did a bit of an experiment with a 20 hr day but, Waiting till spring cause it's too cool in area now.

I think a 22 hour day is where I will restart something but may not be good for all stages.
Shortening the overall day is where I think there may be some offset available to the finish time vs. yield @Richard Drysift points out. Also use the arduino to gradually transition veg to flower 14-21 days seems to work well.
 
Cletus clem

Cletus clem

Well-Known Member
Richard Drysift said:
Pardon my ignorance but..
What the fuck is a sleep initiator? Ambien?
I have been setting my flower room to 11.5/12.5 for years which helps many of the hybrids I run finish in 10 weeks or less. More hours of darkness speeds ripening somewhat to the detriment of lower yield. No earth shattering revelations there.
Over the years I have experimented with decreasing hours of light during late veg phase:
The suns natural cycle outdoors doesn't go 18/6 to 12/12 overnight. Light hours are gradually increased from the beginning of the year until the summer solstice and then darkness slowly increases through autumn and eventually back again to the shortest day on the winter solstice. For thousands of years humans marked these days to know when to plant crops and when to harvest them.
Under indoor artificial lighting we can easily control the light cycle but most growers only use 18/6 or 12/12 depending upon stage of growth. Some strains like sativa doms can stretch out quite a bit after "the flip" because these plants have evolved near the equator which has a lengthier growing season than the rest of the world. Growers have developed many new sativa/indica hybrids to help reduce flower times but the genetics are still influenced by evolution.
Gradually reducing the hours of light from 18/6 down to 14/10 can help reduce stretching which can also increase yield somewhat by growing tight intermodal and lateral branching. The spaces in between the buds produce zero usable end product but by reducing these spaces you increase the amount of potential bud sites thereby increasing yield.
It goes like this...Start at 18/6 and veg until they are of a decent size. Then reset timer to 17/7 for a week. Then 16/8 for another week. Continue to reduce the hours of light by 1 hour a week and by the time they reach 14/10 most strains will begin to throw pistils at this light cycle. Then to 12/12 or 11.5/12.5 or whatever bloom cycle you want to set a week later.
Click to expand...
Look up the emerson effect. Its a far red led, like 740nm-840nm?, usually just a couple diodes. When the lights go out, the far reds turn on for 15 minutes. The theory is that this simulates sunset and signals the plant that its bed time. Normally this process takes about 2 hrs from the time the lights turn off. This gives you 2 bons hours that would be inactivity to give your plants either more light or more darkness. This is all proven science but its ultimate effectivity i cannot vouch for. Rapid led sells a far red flower initiator puck. Its $30 and consists of 4 red diodes on a pcb, a driver and a barrel jack for a 12v power supply. Plug it into a timer to turn on and run for 10-15 minutes right after lights out and youre good to go. Interesting if you like fucking around. I plan on grabbing 1 or 2 at some point and seeing what i can do withem.
 
HideousPenguinBoy

HideousPenguinBoy

Well-Known Member
Emerson Effect is the complimentary effect 680nm and 730nm wavelengths have together, giving a great photosynthetic rate than either of the two alone. The effect of @680nm WAKEUP and @730nm GOSLEEP is separate, though I have zero idea what the name is for that. In general, white spectrum LEDs have enough 680nm to wake your plants up, though I haven't seen anyone run experiments to see it's effect. As for those pucks, they can hit a 3x3 square, so keep that in mind if you are buying for a bigger space.

And yeah, SSGrower, we don't have to put up with natural days anymore, so why not use something other than a 24 hour schedule. The thought with the far red is you are providing 2 more hours of active sleep time, so extending your day to a 26 hour. Since a plant can only absorb a certain amount of photons per day anyway, do you just increase the PPFD to 1066 and drop your 'daytime' to 9 hours? (instead of 800PPFD for 12)
 
SSGrower

SSGrower

Well-Known Member
HideousPenguinBoy said:
Emerson Effect is the complimentary effect 680nm and 730nm wavelengths have together, giving a great photosynthetic rate than either of the two alone. The effect of @680nm WAKEUP and @730nm GOSLEEP is separate, though I have zero idea what the name is for that. In general, white spectrum LEDs have enough 680nm to wake your plants up, though I haven't seen anyone run experiments to see it's effect. As for those pucks, they can hit a 3x3 square, so keep that in mind if you are buying for a bigger space.

And yeah, SSGrower, we don't have to put up with natural days anymore, so why not use something other than a 24 hour schedule. The thought with the far red is you are providing 2 more hours of active sleep time, so extending your day to a 26 hour. Since a plant can only absorb a certain amount of photons per day anyway, do you just increase the PPFD to 1066 and drop your 'daytime' to 9 hours? (instead of 800PPFD for 12)
Click to expand...
I think you are hittikng on a few key points, intensity and duration should be considered though I'm not sure 1 for 1 photon equivalency is needed because during veg plants can look "tired at the end of the day, primary reason I veg for 17 hrs instead of 18. The other is I like prime numbers and 17/7 and 11/13 Are all prime and theyy also happen to be my standard lighting times. I think if looking at extending the day lul or drop in intensity would prove beneficial, ultimately it will boil down to economics tho, is it cheaper to produce a more photons per hour at fewer hours or vice versa? It will depend mightily on if there is an impact to finishing time or days to finish by either lengthening or shortening the day.
 
Richard Drysift

Richard Drysift

Well-Known Member
Cletus clem said:
Look up the emerson effect. Its a far red led, like 740nm-840nm?, usually just a couple diodes. When the lights go out, the far reds turn on for 15 minutes. The theory is that this simulates sunset and signals the plant that its bed time. Normally this process takes about 2 hrs from the time the lights turn off. This gives you 2 bons hours that would be inactivity to give your plants either more light or more darkness. This is all proven science but its ultimate effectivity i cannot vouch for. Rapid led sells a far red flower initiator puck. Its $30 and consists of 4 red diodes on a pcb, a driver and a barrel jack for a 12v power supply. Plug it into a timer to turn on and run for 10-15 minutes right after lights out and youre good to go. Interesting if you like fucking around. I plan on grabbing 1 or 2 at some point and seeing what i can do withem.
Click to expand...
Ok think I am grasping this now. For those who may be trying to follow along but are a total moron like me here's a link that may help shed light on this:
https://www.420magazine.com/forums/grow-lighting/226526-730nm-photoperiodism-emerson-effect-photosynthetic-artificial-darkness.html

So if you are running grow lights that are not of the far red spectrum you are wasting 2 hours of darkness each night while the plant transitions to "sleep mode." The far red spectrum is what the sun gives off at dusk which initiates "sleep." Adding far red (730nm) to your indoor grow allows you to reduce hours of darkness by 2.
 
Cletus clem

Cletus clem

Well-Known Member
Richard Drysift said:
Ok think I am grasping this now. For those who may be trying to follow along but are a total moron like me here's a link that may help shed light on this:
https://www.420magazine.com/forums/grow-lighting/226526-730nm-photoperiodism-emerson-effect-photosynthetic-artificial-darkness.html

So if you are running grow lights that are not of the far red spectrum you are wasting 2 hours of darkness each night while the plant transitions to "sleep mode." The far red spectrum is what the sun gives off at dusk which initiates "sleep." Adding far red (730nm) to your indoor grow allows you to reduce hours of darkness by 2.
Click to expand...
So as noted above, i fucked it up. The emerson effect is using the 2 spectrums together to enhance each other. The flower initiation is using the far red only after lights out for a short period (10-15 min) to put your plants to sleep. It acts as a trigger. Normally when your lights turn out, it would take about 2 hours for your plants to fall asleep. You are combining the 2 tecs, its sort of my fault.
 
torontoke

torontoke

Well-Known Member
Cletus clem said:
The far red will depend on how u use it. 15 min after lights off but continuing with 12/12 is said to shorten ripening time, earlier harvest. The same technique only lengthening lights on, 13/11, 14/10, will give the plant more time for photosynthesis. I guess with potential better yields? In theory, plants take 2 hours to “fall asleep”, with the flower initiator, its said this happens much faster. Plants spend all day using photosynthesis to make sugars that will get put to use wile it sleeps. It becomes a matter of more time to make sugars or more time to put them to use. Or does it really matter?
Click to expand...
I’ve always thought of it as more of a balancing act tbh
Finding a happy medium between the right amount of light to facilitate the growth cycle you choose to run your plants in.
I learned a long time ago that there is such a thing as too much light per sq ft and definitely to much light hrs vs need.
Longer lights on hours won’t give greater yields all the time imo just think of those runforever sativa land races growing in tropical places that take months and put out whispy light weight bud. More or longer light would most likely mean those plants would have much more need for extra nutes and attention in equal amounts
Just like strain selection grow methods vary and everyone is gonna have their preference and reasons for them there’s no right one size fits all method.
 
Chris Edward

Chris Edward

Well-Known Member
I have heard the lighting cycle depends on the strain.
One thing I heard (I believe from GrowMau5) that made sense is to set up a time lapse camera facing your plants, with the lights on for 24 hours during the test.
Then later go back and scrub through the video and watch for the point when the leaves begin to droop. This is when the plant is going to sleep regardless of the amount of light.
Then you will know exactly how long to keep your lights on and when to start your UV sleep initiator.
 
Cletus clem

Cletus clem

Well-Known Member
torontoke said:
I’ve always thought of it as more of a balancing act tbh
Finding a happy medium between the right amount of light to facilitate the growth cycle you choose to run your plants in.
I learned a long time ago that there is such a thing as too much light per sq ft and definitely to much light hrs vs need.
Longer lights on hours won’t give greater yields all the time imo just think of those runforever sativa land races growing in tropical places that take months and put out whispy light weight bud. More or longer light would most likely mean those plants would have much more need for extra nutes and attention in equal amounts
Just like strain selection grow methods vary and everyone is gonna have their preference and reasons for them there’s no right one size fits all method.
Click to expand...
Everything changes though when you change the rules. With indoor growing, most of the parameters are set by you. By triggering the plants to go to sleep like that you are effectively adding 1.5-2 hours to the day as far as current common practice indoor growing is concerned. What do you do with it though? For a long cycle sativa, you could use it to shorten the cycle. I would think the longer the cycle, the more dramatic an effect it could have in the end. If 8-9 week strains can be cut down by 3-7 days, could a 14 week be shaved down by almost 2 weeks? Fun stuff to play with.
 
torontoke

torontoke

Well-Known Member
Cletus clem said:
Everything changes though when you change the rules. With indoor growing, most of the parameters are set by you. By triggering the plants to go to sleep like that you are effectively adding 1.5-2 hours to the day as far as current common practice indoor growing is concerned. What do you do with it though? For a long cycle sativa, you could use it to shorten the cycle. I would think the longer the cycle, the more dramatic an effect it could have in the end. If 8-9 week strains can be cut down by 3-7 days, could a 14 week be shaved down by almost 2 weeks? Fun stuff to play with.
Click to expand...
Ya I can’t really comment on extending the daylight hours it doesn’t interest me at all so I’ve never tried any of it.
Definitely agree everything changes with different light cycles and that’s why I generally stay out of most convos about finish times.
But yes I’d say you could easily cut a 14 week strain back to 11-12weeks with reduced cycles.
 
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