I am curious as to why the current lifecycles have been chosen.

24/0 makes sense. Max amount of light.

12/12 makes sense as thats for flowering.

But where did the 18/6 staple come from? Why is the standard Veg cycle that as opposed to say 17/7, or 19/5?

Have there been any studies to show that 18/6 is the maximized day/night ratio for MJ growing or is it that 18/6 is just a nicer cycle to remember than 17/7?

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First Grow: Bag Seed
http://www.greenpassion.org/f15/buying-vs-trying-13054/

"Such holidays in the sun don't come without sacrifices"

But where did the 18/6 staple come from? Why is the standard Veg cycle that as opposed to say 17/7, or 19/5?

No reason I'm aware of, being a dividable number makes it easier to work with. I use 18/6 cause I think the plants like the breather... Peace.

I was always under the impression that 18 hours came from the number of hours in a 'perfect' day, like if the sun was right over head during summer solstice. 12 hours is the winter solstice.

Gross generalizations but I think that's where the numbers are coming from.

i totally understand the breather part and am all for it...but was curious why a 6hr breather and not a 5hr or a 7hr.

simple-er math could be it....or maybe its like the optimal natural cycle closer to the tropical regions where MJ thrives...

hence the questioning ;-)

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First Grow: Bag Seed
http://www.greenpassion.org/showthread.php?t=13054

"Such holidays in the sun don't come without sacrifices"

what about the FLoewer cycle...

12/12 is easy but is that the maximization of production? What about 13/11 or even 11/13? has anyone ever experimented with that or is there research/literature out there that states that 12/12 is better than something else?

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First Grow: Bag Seed
http://www.greenpassion.org/showthread.php?t=13054

"Such holidays in the sun don't come without sacrifices"

I'm with the dude above ......... my veggies get 24/0 .... my flowers get 12/12.

I have noticed (but was hesitant to ask) that many seem to use something other than 24/0 for the veg cycle. It would seem that anything other than 24/0 would tend to push them towards flower.

Any solid research/evidence links would be appreciated.

Thanks

Feez

18/6 seems to be the point where you receive the most growth per hour of light. It saves 25% on the power usage without suffering 25% slower growth. 24/0 uses more power and gives slightly more growth.

If you are trying to keep the power bill as low as possible, I like 6/6/6/6, it saves 50% on the bill versus 24/0, and if you have multiple lights you can cycle them against one another so your loss in growth is quite minimal.


If you have several thousand watts, this can be handy.

is it ok to put a plant into the 18/6 cycle after being in a 24/0 cycle without stressing or causing any effects ?

i would ease into it. i wouldn't just instantly do it. the seasons transition slowly naturally to begin with

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yeh i can understand that , what about a 1-2 hour a night break down ease it down so over the space of like 3 days bring it into the 18/6 or do 1 hour a night and bring it down over the space of 6 days ?

i would go for the six, good things come to those who wait, after all

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i might start that tonight , turn it off for 1 hour then turn it back on , tomrorow turn it off for 2 hours . etc etc till im at 18/6 , cheers for the advice sprocket

your welcome, just sharing what i have read myself

Hi
My 2 cents
In my limited testing i found this to be in the Veg cycle
24/0 Bigger plants (Taller)
18/6 Smaller plants (Bigger roots) higher yield also.
I pre veg my plants in a small tray containing 5 inch net pots.
I am able to watch the progress of the plants and roots easily
Good luck

Hey,, ive used 11on/13off before from about 2-3 weeks into flower. i didnt notice anything,, i suppose someone would have to do a side by side test with the same clones same lights etc.
All i can say is that it didnt harm the plants.
Peace.

-SBA

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Current Grow.....


..Instead of taking five or six of the prescriptions, I decided to go a natural route and smoke marijuana. -Melissa Etheridge.

..I think people need to be educated to the fact that marijuana is not a drug. Marijuana is an herb and a flower. God put it here. If He put it here and He wants it to grow, what gives the government the right to say that God is wrong? -Willie Nelson

Hi Me again lol
I just can't resist showing how much I know (Or think I know)
In my short growing experience I have found that:
Longer Light in Veg say 24/00 I had taller plants less roots and less yield.
Smaller plants with 18/6 more roots larger yield.
I was growing in a rental awhile back and an inspection was scheduled in like 5 weeks.
I was told that changing the light schedual from 12/12 to 14/10 (10hrs on) would make the crop come in quicker.
I over did it and made it 8hrs on and 16 off.
Cut about 9 days off a 9 week bloom plant.
I started the 16/8 on week 3.5 of my bloom cycle.
Hope this helps
PS: The yield was way down, but got a crop and the smoke was just as good.

fast flowering is generally done using 6 hours of day, and 12 hours of night. The faster finish is created because the plant finishes in the same number of, "days" but each day is 6 hours shorter, giving you a 25% faster flower time.


You can crop out blackberry and some other fast finishers in a month with this technique, but their yield will be down.

I always liked 18/6 for veg and 12/12 for 4 weeks (or until full flower mode, not stretching so much) of flower, and then shorten the daylight times by a hour every 5 days or so. Never had much of a yield issue and not sure how much time I really shaved off. Never tried short days right out of the flowering gate.

In my general experience and from what I've read the reason for the 18/6 lite cycle is two fold.

The energy use/plant growth ratio is optimal at 18/6. As stated above you get the most growth with the most efficient use of your energy. Lower lite cycles will leave room for growth and more lite will cut back on your growth to wattage use.

The second reason is that the idea of a grow show indoors is to mimic an outdoor environment at it's best. The longest day of the summer is an 18 hour day, and the shortest is 12/12. That is why these times have been the standard in indoor growing.

Taken from Jorge Cervantes's Horticulture Grow Bible revised edition.

Many thanks
That is valuable info indeed.
I am sure it is posted elsewhere, just a matter of looking it up.
Thanks again