16/8 vs 24/0 veg test, 18/6 included

nomofatum

Well-Known Member
lifehackers source was how stuff works, which has tons of credible sources. So it's a legit claim, you probably should have paid attention to that before posting.
we are looking at the source of your source's source now?
:clap:

I think you should get a more direct source we are getting into telephone game territory here.
 

Chester da Horse

Well-Known Member
I've learnt a lot by reading through this thread guys

The only thing I would say is that a 400 mh light beaming down on a seedlings will get you less then optimal growth you are you in fact are miniaturizing it . I grew on 24/0 and on 18/6 and never really could tell so when growing I always go by the the less is more rule ,
I feel like my sproutlings are infact miniaturised as you say under the powerful 400W MH light.

My point to add is the 18/6 400W MH regime uses 6.4KWh of electricity but the 24/0 250W setup draws 6KWh. If you controlled for strain/genetic difference/light type/light height and grow medium/ grow room condition variation this would actually be a powerful result in favour of 24/0 and lower power light. There is no way these little seedlings are efficiently using all of that 400W I'm shining on them.

PS: This is a funny thread. Scientific method is not always applied correctly as pointed out by nomofatum, but the OP has contributed something useful for my growing.
 

Tone5500

Well-Known Member
I've learnt a lot by reading through this thread guys


I feel like my sproutlings are infact miniaturised as you say under the powerful 400W MH light.

My point to add is the 18/6 400W MH regime uses 6.4KWh of electricity but the 24/0 250W setup draws 6KWh. If you controlled for strain/genetic difference/light type/light height and grow medium/ grow room condition variation this would actually be a powerful result in favour of 24/0 and lower power light. There is no way these little seedlings are efficiently using all of that 400W I'm shining on them.

PS: This is a funny thread. Scientific method is not always applied correctly as pointed out by nomofatum, but the OP has contributed something useful for my growing.
Best thing you can do is raise that 400 light up and then once you get about 3 or 4 nodes start dropping it back down to around 12" .
 

Chester da Horse

Well-Known Member
Best thing you can do is raise that 400 light up and then once you get about 3 or 4 nodes start dropping it back down to around 12" .
Got 'em at 18" now, thanks.

If only we could get a square answer about the sex determination/light schedule thing... I've read the 'scientific studies' posted here on RIU and Im just as confused as my plants are gonna be if I follow everyones advice on that!

I believe playing girly music to your plants (taylor swift, katy perry, celine dion) helps them put out pistils - can anyone else test this? cos i can't stand that shit.
 

mrblu

Well-Known Member
running anything over 80% is a risk. the breaker can fail and you will cause a fire. its not there to overload circuits all you want.
 

Tone5500

Well-Known Member
running anything over 80% is a risk. the breaker can fail and you will cause a fire. its not there to overload circuits all you want.
And that's why i always run 20amp breaker with 12gauge wire , little over kill but worth it , and a lot of electrical wire fires are from dumbasses trying to run a 14 gauge on a 20amp breaker with twenty things pluged in one outlet causing the wire to catch fire without popping the breaker , and unless your dealing with older style breakers the breakers fail open not closed .
 

rocho

Well-Known Member
Sorry if my answer is coming with almost 2 years of delay.

So are there any solid conclusion about 24/24 lightening...any difference between auto and regular plants?

I know that this was not a scientific experiment but there are also a lot of theorical aspect in support of this.
For example, have you never read the follow informations?( copy and paste from another forum)




"It's been established for many many many years now that cannabis is a C3 plant. It does not need a dark period. C3 plants gather CO2 only during the light period when they are photosynthesizing. As long as the light is on, C3 plants gather and use CO2 for photosynthesis.

Some growers practice a version of anthropomorphism with their plants. They believe that since people need rest, plants do as well. Concerning cannabis, this is not true.

Every grower can make a personal choice about light cycle. They can save on their electric bill or prolong ballast/bulb life. 18/6 can be less of a "shock" when changing over to 12/12 for flowering than 24/0 or heat issues can be addressed by fewer hours of light, but basic botany has proven long ago that cannabis needs no dark period.

Robert Clarke "Marijuana Botany: An Advanced Study"

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.

Ed Rosenthal "Marijuana Grower's Handbook"


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."
Greg Green "The Cannabis Grow Bible"

 

Blenko420

Well-Known Member
Sorry, but totally meaningless when you aren't comparing same lights and clones. This type of experiment leads to false or at least deceptive conclusions. Use the scientific method, we need to reduce this to where there is only 1 variable if you want to test that 1 variable.

Different strain, fail
Different light, double fail
Different time, tripple fail

Three strikes this experiment is out.
Agreed. This evidence is completely useless because you cant possibly put it down to the lighting times it could just as well be the fact that the other is a different strain or the fact that they are growing under entirely different lights.
 

TheChemist77

Well-Known Member
4/0 and 18/6 both share the same problem though. Once you start thephotoperiod 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 thatphotoperiod unitl your plants are mature enough to express their sex."
Greg Green "The Cannabis Grow Bible"









i guess this guy believes seeds are not male or female, but the light determines the sex....in all my years of growing i get better female to male ratio using 18/6, higher blue spec, temps 78f -72f, and a nutrient w higher nitrogen. however at 24/0 same temps, etc the female to male ratio is still 60% females or better.. ill keep my veg 18/6 and bloom 12/12.. i do think of going the gass lanturn routine

to save on electric but i worry it will effect my female ratio,, has anybody tested the GLR light sced starting w seed? i wonder if the GLR light sced causes any stress, more herms, more males, or plants starting to bud.. i just ran grand daddy purple seeds, 2 males 2 females, but both females started to produce buds after 11 weeks in veg 18/6,, all my other mothers are in a veg state.. is KENS GDP prone to be auto??
 

tiltswitch

Well-Known Member
I always veg 24 hrs. Growing for over ten years , and it's definitely quicker growth. The more light the better, Iv never noticed plants being more happy after a rest. Iv read that seed sex is not predetermined, that it's environmental, which makes a lot of sense to me, there's not much info about it though. Read that it's to do with temperature and If you germ at very high temps more females are produced, never tried it though as I'm.a femmed seed user , do commercial and don't have the time or patience.
 

Viceman666

Well-Known Member
First this is a very old thread..
second 18/6 or 24/0 doesnt make any difference for the plant it all depends the light intensity you have there is so much light a plant can use in a day look up for DLI
 

cannabisoldier

Active Member
First this is a very old thread..
second 18/6 or 24/0 doesnt make any difference for the plant it all depends the light intensity you have there is so much light a plant can use in a day look up for DLI
I remember reading a while ago that a 15/9 light cycle will cause flowering. I came here to this thread bc I was wondering if a 16/8 light cycle would cause flowering. I get what you're saying about DLI 100%. But at some point the number of hours of dark cycle will initiate flowering. We know 12 hours will. I wondering what is limit of hours of darkness and maintain veg state. As with all things cannabis. Im sure its strain dependant as well.
 

piratebug

Well-Known Member
Like you were thinking, when a plant flowers is strain dependent! But in most parts of the world, the longest day of sunlight is around 16 hours, so if you veg your plant(s) under 16/8, then those plant(s) vegged under that light schedule won't ever flower! Other than that, most strains begin flowering when they get between 11 hours and 55 minutes of darkness (lambs breath) to 9 hours and 40 minutes of darkness (northern lights), but I have grown a few unusually ones that started flowering with only getting around 9 hours of darkness!
 

OSBuds

Well-Known Member
wondering what is limit of hours of darkness and maintain veg state.
 
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