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18/6 to 24/7 will it cause problems

M

MagusMan

Sup icmag i am growing 4 plants at the moment. they are under metal halide 18/6 and temps are good 24c 55% humidty i read that ed rosethal said you can keep lights on 24/7 this would suit me better because i am running heaters and a dehumidifier.so leecy bill is going up higher. so would be better too run 24/7 but can i change now they are still in veg ? Thanks Magusman
 
M

MagusMan

a good bit i am an insomniac but i see your point a rest for them is better
 

Cvh

Well-known member
Supermod
Give them some rest. Several processes in the plant take place when they are 'sleeping'.
 

mowood3479

Active member
Veteran
Sometimes in winter I will run veg rooms 20/4 or 22/2 just to keep temps up to saitifactory levels.. but I’ve never felt like the plants liked 24/0 light schedule..
No issues switching from 18/6..
To me it’s More important temps remain in optimal range then plants get 6 hours of dark (although I believe they need a few hours without hid lighting per day)
 

Ringodoggie

Well-known member
Premium user
Ed Rosenthal and several other well documented writers have stated that 24/0 is the way to go. They claim it minimizes stretching and can increase yield up to 30%.

Personally, I prefer 18/6 during the early veg stage because, as I recall, the critical cycle (night cycle) helps to produce an enzyme that promotes root growth (can't recall the name of that enzyme). I have found clones root much better under 18/6.

Still, for many years the 'experts' have mostly all sworn by 24/0. Guess I'm not an expert. LOL




.
 

Switcher56

Comfortably numb!
Ed Rosenthal and several other well documented writers have stated that 24/0 is the way to go. They claim it minimizes stretching and can increase yield up to 30%.

Personally, I prefer 18/6 during the early veg stage because, as I recall, the critical cycle (night cycle) helps to produce an enzyme that promotes root growth (can't recall the name of that enzyme). I have found clones root much better under 18/6.

Still, for many years the 'experts' have mostly all sworn by 24/0. Guess I'm not an expert. LOL
.
Please quote Chap. & verse. i have Ed's book and I can't find it in there. AAMOF he recommends 12/12 during flowering.

Pg 375

  • if plants receive 18hrs of light they will not flower
  • if the light cycle is int erupted by a dark period, they will not flower
  • when plant receive 10-12hrs of darkness they will flower
  • if the dark cycle is interrupted, they will not flower.
 

Ringodoggie

Well-known member
Premium user
I thought we were talking about the veg stage. Definitely 12/12 during flower but during veg, most all books recommend 24/0.


I am plowing out of a fucking foot of snow today but I'll see if I can flip through some of Ed's books.
 
M

MagusMan

Please quote Chap. & verse. i have Ed's book and I can't find it in there. AAMOF he recommends 12/12 during flowering.

Pg 375

  • if plants receive 18hrs of light they will not flower
  • if the light cycle is int erupted by a dark period, they will not flower
  • when plant receive 10-12hrs of darkness they will flower
  • if the dark cycle is interrupted, they will not flower.

This is a direct quote from Ed Rosenthal whom most of you know is a marijuana growing guru:

...marijuana plants photosynthesize as long as they receive light as well as water, air, nutrients and suitable temperature. Photosynthesis is the process in which plants use the energy from light (primarily in the blue and red spectrum's) to combine carbon dioxide (CO2) from the air and water (H2O) to make sugar while releasing oxygen to the air.

Plants use sugars continuously to fuel metabolic processes (living) as well as for tissue building. The plant combines nitrogen (N) with the sugar to make amino acids, the building blocks of proteins. They are the substance of plant tissue. When the light is off, the plant's metabolic processes, respiration and growth, continue.

The plant can photosynthesize continuously so it produces the most energy and growth when the light is on, continuously. Continuous light does not stress the plant, which reacts somewhat mechanistically to it.

Plants under an 18-6 light-dark regimen are producing sugar only three quarters of the time. They are thus growing at only 75% of their potential. Leaving the light on continuously will result in bigger plants, faster, which leads to higher yields."
 
M

MagusMan

"The following information is straight from Greg Green's "The Cannabis Grow Bible"

Cannabis is a light demanding plant. Professional growers keep the light on their plants using the 24/0 photoperiod for this reason. Plants that grow under 24/0 flourish and do not need a quantity of darkness in order to rest and perform photosynthesis properly. Plants that are grown in optimal conditions under 24/0 light regime grow vigorusly and the benefits of a 24/0 photoperiod can be seen actively in the results. More nodes are formed, more branches are created, leaf numbers increase, the plant is growing at its finest.

Some growers opt to use 18/6 as their photoperiod. This is 18 hours of light, six hours of darkness light regime. Under these conditions the plant will grow quite naturally but not as vigorously as the 24/0 photoperiod.

The 18/6 photoperiod expels 3/4 the amount of light that a 24/0 photoperiod does. Although this does not mean that a plant produces 1/4 less leaves,branches and nodes under the 18/6 photoperiod, it certainly does show the correlation between light and cannabis growth. As we have said already, cannabis is a light demanding plant. There are no problems associated with 24/0 and although some have attributed cannabis sexual dysfunction (the hermaphrodite conditon) to 18/6 photoperiod these problems are actually the result of heat stress.
A 24/0 photoperiod requires that your grow room temperature be kept well monitored. The 18/6 option is cheaper to run. You use a quarter less electricity and this will have an impact on your electricity bill. Also the 18/6 photoperiod will generally extend the bulb's lifespan. During the 6 hours of darkness the grow room is allowed to cool down for this period but a well maintained good grow room setup should not require a cooling down period.

24/0 and 18/6 both share the same problem though. Once you start the photoperiod you should keep that way especially when the plants near maturity (the preflowering stage). An irregular photoperiod can cause more males than females to develop. It can also cause sexual dysfunction to appear. Whether you choose 24/0 or 18/6 as your vegetative photoperiod try to keep that photoperiod unitl your plants are mature enough to express their sex."
24/0 is superior insofar as plant growth
 

Ringodoggie

Well-known member
Premium user
Here's a couple I grabbed with a quick search. I thought it was well known that 24/0 was far better than 18/6. I prefer 18/6 and I have often been the brunt of criticism for it in the forums. Odd that everyone here goes the other way. :)



Ed's "Grower's Guide"


Chapter Twenty-One - Early Growth
Once the seeds germinate, the light is kept on for 18-24 hours a day. Some growers think that
there is no significant difference in growth rates between plants growing under 24 hours of light a
day (continuous lighting) and those growing under an 18 hour light regimen. In controlled
experiments there was a significant dif- ference: the plants get off to a faster start given
continuous lighting.




Ed's "grower's Handbook"...


7. 3 Light Cycle and Distance of Lights from Plants


Some growers leave the lights on up to 24 hours. A cycle longer than 18
hours, may increase the growth rate, especially if the plants are not saturated with light. A longer
cycle is helpful in small gardens, such as under standard four-foot fixtures.
 

Switcher56

Comfortably numb!
This is a direct quote from Ed Rosenthal whom most of you know is a marijuana growing guru:

...marijuana plants photosynthesize as long as they receive light as well as water, air, nutrients and suitable temperature. Photosynthesis is the process in which plants use the energy from light (primarily in the blue and red spectrum's) to combine carbon dioxide (CO2) from the air and water (H2O) to make sugar while releasing oxygen to the air.

Plants use sugars continuously to fuel metabolic processes (living) as well as for tissue building. The plant combines nitrogen (N) with the sugar to make amino acids, the building blocks of proteins. They are the substance of plant tissue. When the light is off, the plant's metabolic processes, respiration and growth, continue.

The plant can photosynthesize continuously so it produces the most energy and growth when the light is on, continuously. Continuous light does not stress the plant, which reacts somewhat mechanistically to it.

Plants under an 18-6 light-dark regimen are producing sugar only three quarters of the time. They are thus growing at only 75% of their potential. Leaving the light on continuously will result in bigger plants, faster, which leads to higher yields."
I guess the Q is, what is that extra 25% costing you, and how do you calculate it? I believe that is why some settle for a 20/4 cycle. Squeezing a little bit more out of it, while allowing the plant a rest period. I guess the Q could be... if mother nature (who knows better) turns the lights off at night. Why are we going against the grain?
 

944s2

Well-known member
ICMag Donor
Veteran
A room full of 48 seed grown plants ,,all different varieties and given 24/7 light regime before going to bloom,,,,
Very happy and healthy in ten litres pots of all mix,,,
Plenty of time to sleep during there ten weeks ( at least) of bloom,,
Each to there own,,,s2:tiphat:
 
M

MagusMan

I guess the Q is, what is that extra 25% costing you, and how do you calculate it? I believe that is why some settle for a 20/4 cycle. Squeezing a little bit more out of it, while allowing the plant a rest period. I guess the Q could be... if mother nature (who knows better) turns the lights off at night. Why are we going against the grain?

i was just thinking it would be better off 24/7 because.
when i turn the light off i have to use a large heater
because tent in large room and i run a 290watt
dehumidfier so i am burning over 500watts in dark cycle
and only burning 400watts lights on so 25% extra growth sounds better
too me.but i dont no anything because this is my first grow so thats why i am asking questions.also my temps humidty stay constant when lights on i dont no if i can switch from 18/6 too 24/7 now because i would do it if it didnt affect plants now, but maybe next grow i will do it for sure
 

Ringodoggie

Well-known member
Premium user
I run all my grows at 18/6 for the first month, from clone day to 1 month. Then, I go 24/0 for 1 month. By then, they are usually ready to flower.

So, switching from 18/6 to 24/0 won't hurt you because I do it all the time.

I do remember one grow not too many years ago where I left it 24/0 the entire time because it was getting too cold during the dark 6 hours. I saw no real difference.




.
 

djibra

Active member
i had to have my veg light on 24/0 ant the girls were fine.. veged nice but didn’t show signs of sex..200cfl was the bulb.. and i you’re ok if you change from 18/6 to 24/0 or whatever as long it’s not flowering regime
 

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