Growing with an 18 hour day/night cycle

Thoughts?

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Growing with an 18 hour Day/Night Cycle

The Theory
The theory behind the 18 hour Day/Night cycle is that during a normal 24 hour light cycle plants will usually achieve high growth rates peaking at 100% capacity during the first 50 - 60% of the day. The growth rates will then diminish rapidly and the last 20 - 30% of the day achieves minimal growth. So by reducing the length of the day we are triggering an increased growth mode where the growth rates are at their peak for the majority of the day. This effectively achieves a very fast growth cycle with full yield potential.

NOTE: To achieve these incredible growth rates it is important to provide maximum light intensities and CO2 enriched conditions. The recommended lighting is 600W per square metre.


The Cycles
Vegetative Cycle - Lights ON 14 hours, Lights OFF 4 hours
Flowering Cycle - Lights ON 6 hours, Lights OFF 12 hours

The Benefits
The growth acheived during an 18 hour cycle can be the equivalent to that acheived during a 24 hour cycle. So by running 18 hour cycles the same growth and yield can be acheived in 75% of the time.

Reduced day lengths also mean reduced power consumption. Grow more and use less power. Who can argue with that?

For example, an average crop grown from seed using a 24 hour day/night cycle will have a 4 weeks grow cycle and an 8 weeks flower cycle. This equates to 28 days @ 18 hours a day and 56 days @ 12 hours a day = 1176 hours of light over 12 weeks.

An accellerated crop using an 18 hour day/night cycle will achieve the same yields using a 3 week grow cycle and a 6 week flower cycle. This equates to 21 days @ 14 hours a day and 42 days @ 6 hours a day = 546 hours of light over 9 weeks resulting in a 40% reduction in power consumption and a 25% reduction in crop time.

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wow, this is really interesting, i have ordered my setup for my 1st grow and i will certainley try this method starting next week. Do you have any pictures of plants grown with this method?

Thanks for sharing the information mate

This is incredible... if this works, this could be a major energy and time saver!

I'm excited to try this out in about 2 months, after this batch is all harvested.

Do you think would work for any plant? Plants are plants, they veg they flower they die. This would save us lots of money on power is all crops worked this way.
Best of luck, I'm subscribed.

peace

"Do you think would work for any plant?"

I can't see why it wouldn't for any 12/12 marijuana plant, like you said - plants are plants.

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The idea is that you have an 18 hour light/dark cycle (6 light/12 dark) = one 18 hour day. So in 2 x 24 hour days you're plant grows 3 x 18 hour days. Most (all) of the trich and THC production are done at night, the day is just to gather energy. The plant absorbs most of the light from a 12 hour light period in the first 6 hours, so instead of inefficient light absorbtion (sp) for the last 6 hours of the light cycle the plant goes into it's 12 hour dark cycle.

7 x 24 hour days = 168 hours = 7 dark periods

9 x 18 hour days = 162 hours = 9 dark periods



Pretty cool

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Great concept, did you think this up?

Peace

No, I was googleing for "reducing flowering time marijuana" and the article came up in another forum.

The rotating 6 hours of light would be the deal breaker for me - I don't need the extra bud bad enough to plan my gardening around an 18 hour day.

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so does this actually work? any recorded grows using this schedule?

i use a PLC instead of timers so setting this up would be easy... I'm working with a strain i've done several times, i'll do it again and see if my results are the same (hopefully they wont all just go hermie)

I run 2KW so i could REALLY use that energy savings.... when i am in veg mode, my house goes over 4000 KWHrs per month

I don't know if it would work ... it's an article, presumably from someone knowledgable, not the insane ramblings of a forum member.

If the part about the plant absorbing most of it's energy in the first 6 of 12 light hours is correct then I think it could work.

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I'd say if it will work some hot shot somewher has written an article about it.
I'll see what I can find.

Peace

hmm wonder how i could configure my timer to do this

u will have to make 18h day timers...

BloodShot420 said:

u will have to make 18h day timers...

Click to expand...

or change your timer settings every day... but i think that's not that hard since we all love spending time in our grow gardens...

there is another timer called a cyclic timer that could work...

or "harvest master" makes some expensive one...

changing them daily is not a good option - i had 6 timers that would need to be reset.... i like just peeking in on the weekends

What does a PLC setup cost?

they are modular, so as low as about 225, but with everything including co2 sensor about $650

Is there any proof of this light schedule working?!? Wouldn't this be the standard of growing instead of the 18/6, 12/12 if the harvest was the same? I guess what I'm saying is if this worked why wouldn't everyone be doing it this way?

yes, its still experimental... but maybe slightly past theory

it wont the plants need 12 hours of uninterrupted darkness in order to initiate flowering. marijuana constantly produce a flowering hormone called phytochrome. Phytochrome initiates flowering,but if phytochrome is even exposed to a flash of light it is rendered inactive. to initiate flowering marijuana plants need a long and uninterrupted period of constant darkness each night for about two weeks.

flowering is 6 on 12 off....