24/12 day night cycle shortens flowering time?

Synthamesc · Jul 12, 2021

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 12-hour night and flour like normal but it would be getting more hours of sunlight for week then in a 12 12 schedule.

So I decided to do some research and see if there is anything out there to corroborate my hypothesis. And I found this:

Grow Faster With Long Light Cycles Written by Professor Lee

Indoor growers can speed up the flowering cycle of traditional and feminized strains of cannabis by simply changing the amount of light

www.weedworldmagazine.org

I was wondering if anyone has any thoughts about this? Or has tried it? I'm about to start flowering and I like experiments.

BoostNBuds · Jul 12, 2021

I'm skeptical, sounds too good to be true lol. Keep me posted on the progress.

-Ben

Vintaw · Jul 26, 2021

From a logical point of view it sounds like it would work. From a grower's point of view it sounds too good to be true. I'm interested, are you going to put it to the test? Hell if I can swing it, I may try it myself. Awesome post. Keep good stuff like this coming.

GrowHobo · Jul 26, 2021

Got me staring at my old analog timer scratching my head lol.

Synthamesc · Jul 27, 2021

OK... So I was doing some research and I fell down the rabbit hole on light. I watched this 45 minute long video from Dr. Bruce Bugbee from Apogee Instruments. He broke down how cannabis absorbs light and the 8 things you need to have in the sweetspot for all grows, really informative. I recommend watching if you like all the science that goes with growing (link below). Any way, he goes on to explain how the key is the DLI, or Daily Light Integral, and the amount the plant can take. PPFD is the density of your light per second that is hitting your surface area. DLI is the amount of PPFD in a day cycle. They found that production tops out at around 40 DLI and the plant has no further benefit from light.

Basically, if you download a light meter app. You can see what your light is putting out and adjust accordingly. I have my light at 93%, with the IR bar on but not the UV, and have 3 feet between my lamp and closest top. My plants are getting 43 DLI over a 12 hour period and they are loving life. After 40 DLI the cells need the night in order to recover. So the 24/12 technique will work but for someone with a light that has a lower PAR value.

I used the app "PPDF Meter" to see my LUX, PPDF, and DLI. The screen dimmer sensor in the phone is how it works. Helps with light power, angle, hight.

Also, BEST LIGHT OF ALLLL TIME

27 days between the 2 photos.
Follow the grow

HydroTrolly grow journal by Synthamesc - GrowDiaries

"HydroTrolly" cannabis grow journal. Strains: ILGM Green Crack by Synthamesc. Grow room 1, growing in . Harvest yield, seeds review, grow details.

growdiaries.com

Check out the light

LED Grow Lights | Best Grow Lights for Indoor Plants - Medicgrow

Medic Grow LED is one of the best LED grow light manufacturers. We have smart, fold and spectrum series. Get higher yields with our full spectrum led grow lights NOW!

medicgrow.com

Dr. Bugbee

Observationist · Dec 18, 2021

bruh PPFD meter APP?

Observationist · Dec 18, 2021

Observationist said:
bruh PPFD meter APP?

im trying to figure out how to use it and check the accuracy. pretty cool.

hawkman · Dec 18, 2021

when growing 100% sativa strains - give your plant a 24-36hr darktime before your 12/12 switch - this will shorten flower x by 1-2 weeks -

mastiff · Dec 18, 2021

I have been trying to explain this to a friend. He waited until Hsvits kosher kush started flowering and get this he put them in 18 hours of darkness and 6 hrs of light. I fought this strategy with him until . He is now in the 4 th week of flower. They have buds and getting hardier. From what I see is that you lose yield a lot . How the smoke comes out is yet to see. He knows someone who grows But more like a farmer that likes to speed things up . If your not a farmer and not growing pounds I would stay with the I guess traditional easy way . how many times can we reinvent the wheel, I believe in the kiss method keep is simple stupid. please excuse me and correct me because I myself might not know wtf I'm talking about but we all learn something knew on every grow. I myself is not that well experienced enough yet to try this. I will follow this carefully because this subject has a lot of people scratching there heads. Will get back on this once the smoke is tried out . Thanks for the great post

costanza · Dec 18, 2021

Synthamesc said:
OK... So I was doing some research and I fell down the rabbit hole on light. I watched this 45 minute long video from Dr. Bruce Bugbee from Apogee Instruments. He broke down how cannabis absorbs light and the 8 things you need to have in the sweetspot for all grows, really informative. I recommend watching if you like all the science that goes with growing (link below). Any way, he goes on to explain how the key is the DLI, or Daily Light Integral, and the amount the plant can take. PPFD is the density of your light per second that is hitting your surface area. DLI is the amount of PPFD in a day cycle. They found that production tops out at around 40 DLI and the plant has no further benefit from light.

Basically, if you download a light meter app. You can see what your light is putting out and adjust accordingly. I have my light at 93%, with the IR bar on but not the UV, and have 3 feet between my lamp and closest top. My plants are getting 43 DLI over a 12 hour period and they are loving life. After 40 DLI the cells need the night in order to recover. So the 24/12 technique will work but for someone with a light that has a lower PAR value.

I used the app "PPDF Meter" to see my LUX, PPDF, and DLI. The screen dimmer sensor in the phone is how it works. Helps with light power, angle, hight.

Also, BEST LIGHT OF ALLLL TIME

27 days between the 2 photos.
Follow the grow

HydroTrolly grow journal by Synthamesc - GrowDiaries

"HydroTrolly" cannabis grow journal. Strains: ILGM Green Crack by Synthamesc. Grow room 1, growing in . Harvest yield, seeds review, grow details.

growdiaries.com

Check out the light

LED Grow Lights | Best Grow Lights for Indoor Plants - Medicgrow

Medic Grow LED is one of the best LED grow light manufacturers. We have smart, fold and spectrum series. Get higher yields with our full spectrum led grow lights NOW!

medicgrow.com

Dr. Bugbee

that light looks incredible. I swear every time I buy a new light, 6 months later I see one I like better.

mastiff · Dec 19, 2021

Awesome post , most informative , great read . I love this .

ChairmanFester · Oct 27, 2025

Synthamesc said:
OK...

I know this is old, but also it's GOLD. Thanks!

ChairmanFester · Oct 27, 2025

@ForestSpirit check out some of the light info here for environmental conditions

24/12 day night cycle shortens flowering time?

24/12 day night cycle shortens flowering time?

Synthamesc

Grow Faster With Long Light Cycles Written by Professor Lee

BoostNBuds

Vintaw

GrowHobo

Synthamesc

HydroTrolly grow journal by Synthamesc - GrowDiaries

LED Grow Lights | Best Grow Lights for Indoor Plants - Medicgrow

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Observationist

Observationist

hawkman

mastiff

costanza

HydroTrolly grow journal by Synthamesc - GrowDiaries

LED Grow Lights | Best Grow Lights for Indoor Plants - Medicgrow

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ChairmanFester

ChairmanFester

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