Going to 12-12 light cycle questions.

#1cheesebuds

Well-known member

Veteran

• May 26, 2018

• #1

Im planning on starting the 12-12 light cycle either today or tomorrow. The plants are growing gr8 for now and the lights are on 18-6 atm. Can I just switch to 12 12 or should i add more darkness each day till i get to 12-12

I read that:
"While simply changing to a 12/12 light cycle will induce flowering, there is a trick to jump start the process. Between the switch from an 18/6 to a 12/12 light cycle, let your plants sit in total, uninterrupted darkness for 36 hours. This will cause the PFR*to drop substantially, giving the plants a strong signal to flower. After the 36 hours of darkness, begin the 12/12 light cycle. In a side by side experiment, I saw significant results from this method. Be sure to flush out high nitrogen “grow” fertilizers from your growing medium and change to a high-phosphorus “bloom” formula. Also, adding high potassium supplements for the first two weeks can help increase rapid bud development".

Any truth to this?

 

eric2028

Well-known member

Veteran

• May 26, 2018

• #2

I just switch to 12/12. Also I’m not sure I believe the high p theory for bloom. I run jacks hydro with the same p throughout with good results.

 

R

RolandtheHead

Member

• Jun 1, 2018

• #3

I usually just go to 12/12. I experimented with gradually shortening the light day, but didn't see any difference.

I believe BOG advocates the 36-hour jump start. DJ Short recommends going to an 11/13 light cycle. There are different theories.

 

MJPassion

Observer

ICMag Donor

Veteran

• Jun 2, 2018

• #4

PFR is the plants method for timing light cycles. It’s built up & used up on a daily cycle & can be manipulated using deep red light.

 

G

Gr33nSanta

• Jun 2, 2018

• #5

Ive been growing perpetual for years, in my context, it does not make sense to mess with the timers, there are always plants at different stages of growth. So I keep it 12/12 year round. If it ain't broken, do not fix it!

 

Azeotrope

Well-known member

Veteran

• Jun 2, 2018

• #6

I went through a phase where I reduced the light schedule incrementally. Worked well.
I have at times just flat out made the switch from 18/6 to 12/12 in one quick visit to the time clock. Worked well. Then, I recently had to shut the lights off for 32 hours to get the lights on of this 11/13 to start at a time that worked for life and all. The tops of the girls were a bit yellow when the lights came back on, but, only for a day or two. Of the 5 beans planted, I got 4 females and one hermie.

So, over the many years, they have all worked for me.


I think it is just best to make sure you lock in the schedule for good once you hit the first 12/12 cycle or more than 12hrs lights off. Once you are there don't shorten the dark time or lengthen the light time.

Best of luck to you!

 

Switcher56

Comfortably numb!

• Jun 2, 2018

• #7

IMHO I believe that incremental darkness is an over cautious way of thinking. The theory behind the 24-36 hrs of darkness makes perfect sense (in theory anyway). So either flip 'em or, tell them they are dying with a 24 hr dark cycle before the flip. None of this sneaking up on them type of BS


That being said, I understand the way mother nature's clock works (progressively less daylight) but we are artificially reproducing mother nature! It is also my HO that mother nature contains more elements than what we artificially reproduce.

 

Azeotrope

Well-known member

Veteran

• Jun 2, 2018

• #8

I agree that the gradual reduction in light hours is more time consuming and tedious without much noticeable benefit if any. Had to try it several times with different strains to come to that conclusion though.

 

Switcher56

Comfortably numb!

• Jun 2, 2018

• #9

Azeotrope said:

I agree that the gradual reduction in light hours is more time consuming and tedious without much noticeable benefit if any. Had to try it several times with different strains to come to that conclusion though.

Click to expand...

I have seen both arguments and have concluded exactly what you have mentioned.

I am currently growing 4 different strains and see how they will do. Only my Indicas (2) will be flowered indoor. The Sats will be going outside in the greenhouse when ready and have had chance to acclimatize themselves (semi-shade for a week) then allow mother nature to run its course.

 

#1cheesebuds

Well-known member

Veteran

• Jun 16, 2018

• #10

thanks for the info all. 12-12 is under way.

 

3snowboards

Active member

• Jun 16, 2018

• #11

Too late for u to do it now

I always do a 24 hr dark when I flip from
24/0 to 12/12 .
Just happened to do that Monday 6.11.

Lights on 6.12

I believe it initiates flower about a week faster

Stretch started day 3 6.16

 

green404

Member

• Jun 16, 2018

• #12

I just flip to 12/12, I do like to keep it at the same watts for a day of to before I turn up the lights, less changes to get used to.

I tried 24hrs dark before never noticed a difference.

 

S

Sign

Member

• Jun 17, 2018

• #13

I tried 72 hours dark before flip and didn't see a difference. Might be something to it but not enough difference for me to observe.