Reduced photoperiod in flowering

[Dank_Diggler]

Hey guys! I've been lurking for years just decided to join. I'm a 20+ year grower that has things pretty dialed in for the past few years. Some time ago I had a grower tell me that he switched to only a 6 hour light period. It kinda blew me away hearing that. However this is a grower that I know has his ducks in a row. He claims that with the excessive amount of light CO2, and proper use of the VPD in his environment the only reductions that have occurred was in his utility bills. I generally will shorten my light hours at the end of flower. This guy runs 6 on the whole flower period with no decrease in yield. His reasoning behind this is the photosynthetic cells act like batteries once charged they are done absorbing radiation. Just curious to think what you guys think about this.

 

[torontoke]

I don’t think 6hrs is enough but perhaps the guy is onto something.

 

[XipXipXoom]

It is true that plants can only absorb a limited amount of light per day, so if he has very intense lighting, it could be possible. I like to start at 12/12 and decrease by 15mins every other week.

 

[Gquebed]

I flower at 10/14 now. No yield loss. Wondering if i can cut back more now...

 

[Dank_Diggler]

I definitely think it's something worth looking into. At the moment I'm not running any strains that I'm familiar with the yield expectancy. Once I find some good keeper phenos I'm down to experiment.

 

[torontoke]

I flower at 10/14 now. No yield loss. Wondering if i can cut back more now...

I definitely think it's something worth looking into. At the moment I'm not running any strains that I'm familiar with the yield expectancy. Once I find some good keeper phenos I'm down to experiment.

http://rollitup.org/t/my-8hr-flowering-experiment.865489/page-61#post-13447665

http://rollitup.org/t/reduced-hour-light-cycles.946754/

 

[Dank_Diggler]

Nice!! that older one is a bit lengthy to read the whole thing. Do you still run a 8hr light period?

 

[torontoke]

Nice!! that older one is a bit lengthy to read the whole thing. Do you still run a 8hr light period?

Yes

 

[XipXipXoom]

Yes

Do you run 8/16 then? Have you ever tried 8/12, so you get 72 light cycles in 60 days, and does that shorten flowering times?

 

[torontoke]

Do you run 8/16 then? Have you ever tried 8/12, so you get 72 light cycles in 60 days, and does that shorten flowering times?

I’ve always wanted to try shortening the overall day but I’ve not found a timer I could program to do it.
Just using 8/16 I have shaved a week plus off of most strains.

 

[chemphlegm]

 

[torontoke]

Wtf?

 

[XipXipXoom]

I’ve always wanted to try shortening the overall day but I’ve not found a timer I could program to do it.
Just using 8/16 I have shaved a week plus off of most strains.

What you'd need is a 7 day digital timer with more than 1 off/on event per day, like a GE 15136.
Then if you program it to start the first 12 hours of the first day as a dark cycle, then 6hrs40mins of light, then rinse and repeat 12 off, 6:40 on, you'll get 9 light cycles in 7 days.

or do it 6 on, 12:40 off, or anything inbetween.