Welcome your opinions on this what you think?

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kathleenbilly

Well-Known Member
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 acheive 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 acheives 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.
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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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BSIv2.0

BSIv2.0

Well-Known Member
Hey Kathleen...I read your post and have a question....

For veg: 14/4 For flower: 6/12....What about the remaining 6 hours?

I know its me missing something. Help me out.
 
K

kathleenbilly

Well-Known Member
Well it works by using the veg for example on for 14 hours then off for 4 hours and then back on after the 4 hours for 14 hrs again following that cycle until they are ready to move over.

The same would principle applies to the flowering cycle. Hope this helps :blsmoke:
 
mal_crane

mal_crane

Well-Known Member
Well I am somewhat of an experienced growing with over 20 grows under my belt. I've just never heard of such a thing. So you only use 18 hr grow days instead of 24 hr is what you're saying right? 14 hours seems like too little of a time period to reach maximum growth. And I'm don't really think that it would work for the flowering cycle because plants have to have a full 12 hours of darkness to flower.
 
K

kathleenbilly

Well-Known Member
Yes i hear you,

Normally when flowering they need 12 hours of light however this theory is saying that after 6 hours the plants do not really benefit from the light and on that basis is the foundation of this whole process.

I'm not saying it works or is right or wrong, but for the difficulty of setting the timers i was going to give it a go but you just can't get an 18 hour timer :mrgreen:


Maybe i will try it manual at some point in the future.........What if it works out to be proven ! :peace:
 
mal_crane

mal_crane

Well-Known Member
No, they have to have twelve hours of darkness to convince them to flower, just like in nature. Am I wrong? If it works then I'll give you rep++ lol I just don't think its possibility to flower under those hours. Definately might be on to something for vegging, I'll have to look into it. But as far as I know, flowering has more to do with the fact that they need 12 hrs of darkness. Maybe I'm wrong and if so, someone please let me know.
 
K

kathleenbilly

Well-Known Member
I think you have mis-understood,

They do get 12 hours of darkness, continously throughout the flowering stage.

18 Cycle.

6 hours of light..then your 12 hours of darkness followed by 6 hours of light, followed by 12 hours of darkness, 6 hours of light.........etc get the idea so they are getting the darkness hours it's the light hours that are reduced.

The problem of this is because it's 18 hours it's very difficult to impliment into practice with timers which all work on a 24 hrs cycle.

The start and stop times of lights on shift every day that's a pain and would need to be done manually.....''
 
mal_crane

mal_crane

Well-Known Member
Ah, sorry about that no wonder I was so confused. I understand a little better now. I'm still not so sure that 6/12 would be a good flowering schedule tho. I'd love to see someone try this. It would take a lot of work without having an 18hr timer. If you do this please let me know how things work out.
 
K

kathleenbilly

Well-Known Member
Yes agreed it would be great to see what would happen,

Myself i'm not set to try at this stage, however i will put it to the test and get the answers this theory deserves some time soon...'' :blsmoke:
 
L

LeSpliff

Active Member
I'd think cannabis being from planet earth would cycle better with a 24 hour day. IMHO. Could be they need 12 hours of light, rather than 12 hours of darkness, or both makes sense to me.
 
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