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optimum light cycles

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for veg it is 19-20/ 4-5 dependign what ya like , plants can only go through so much photosynthisis in a day which is up aroudn 20 hours ,


many veg on 24 hour lighting but I find the plants are not quite as healthy and are more prone to problems so the extra hours of light are little help or improvement ( guess it's kinda like if we go days without sleep aswell)


For flower it's ofcourse 12/12 but if ya wanna get tricky and get a bit mroe light hours you could really go for 14 hours on and 12 hours off , as long as you get 12 dark hours it's all that matters


hope that covered what ya needed

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All plants have a vegetative stage where they are growing as fast as possible after the plant first germinates from seed. It is possible to grow plants with no dark period, and increase the speed at which they grow by 15-30%. Plants can be grown vegetatively indefinitely. It is up to the gardener to decide when to force the plant to flower. A plant can grow from 12" to 12' before being forced to flower, so there is a lot of latitude here for each gardener to manage the garden based on goals and space available.


I veg mine for 24/0 and I have noticed that the plants do veg alot faster with them on 24.

But yea everyone does it differently. :D



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gotta say I have done both and have noticed not even close to that kind of difference , the didn't do "badly" under the 24/7 but they definatly showed more signs of stress than those that where given a little darkness, I don't have my copies of Indoor MJ culture with me or Mj botany but both talk about a 24 hour light cycle being bad for the plant's health despite it's ever so slight increase in growth, the Indoor Bible actualy says specificly that it is a waste to power a room for 24 hours because the plants don't take in any extra light after a certain time frame , ppretty sure they acually say it's 18 hours aswell not even as high as 20


there is also the argument that without the energy goign to the roots durign a dark period that that you won't get asgood of a root system as you will if you give them some sleep , I can't remember the name of the hormone but it lives nativly in mj and is in the leaves during the day and then goes to the roots at night .... buy cutting out a dark cycle you skip the change between the two , another reason that I turn mine off though besides all the stuff about the plants actuall growth patern is that it gives the room a chance to cool down a bit so that heat doesn't gradually just build and build


Pretty sure luke will shed some light on what the hormone or whatever it is is called , alternitivly I'll pop up the name when I'm home B)


But as said there are allot of different ways to grow and choices to make so doign whats best for you is what will give the best results

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Guest Eikel

In short:


MJ doesn't NEED sleep to survive, however it is better for overall plant health to give it a dark cycle even in the veg stage. It doesn't need to be a long dark cycle, infact I'm contemplating moving from 18/6 back to 20/4 for my plants.


24/0 will definately work and for some strains that auto-flower it's a necessity for mother plants, however my personal preference is to provide some dark period.


Here's a good article on it from OverGrow:


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Sweet, well there you go.

I used to run mine on 18/6 but my timer crapped out and stuck on. I noticed a difference in growth whilst it was on.

It was actually the growth that made me realise that the timer was stuck on.


it increased the temps in the grow room a little, So the next winter me and a mate did a comparison grow. We used the same clones, system, light etc.


I went 24/0 and he stuck with 18/6.


Mine was ready to be turned and his was about half the size. But yea mine was showing a few more problems than his did. So the stress thing sounds right.

He yeilded about 12 ozs and I got 10. but mine was ready first.


I think im going back to 18/6 for this next grow, just to see what the difference in plant health is like. And also to try and drop my power bill a bit.



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