Is 24 hours of light continuously 24/7 bad for my plants??

[jlve187]

I have about 9 plants and they are seedlings about 6 days old getting big now but i havent gave them a rest yet i was thinking about giving them about 6 hours of darkness tonite because they been going for 24/7... What do you guys think??? Is 24/7 to much for them and should i give them a resting period?????:jointsmile:

[the image reaper]

that is the oldest argument in growing ... in MY opinion, plants need the dark cycles to reach their full potential ... I can't give hard evidence supporting that, but after a lifetime of growing, and trying alternative methods, I still use 18/6 for vegetative period, and 12/12 for the flowering period ... I just haven't seen improvement by moving much off that schedule ... cannabis is so tough, it will adjust to damn near anything, but there's nowhere on the entire planet, that is fully lit 24 hours a day (except, maybe Las Vegas :D) ...

but, here's a VERY interesting theory, on using light periods, to influence the sativa characteristics, by DJ Short, the famous breeder ...

Breeding tips | Cannabis Culture Magazine (http://www.cannabisculture.com/articles/2600.html) ... thought-provoking :smokin:

P.S. - young seedlings, transplants, and clones probably need the darkness most ... the plant is busier building a root system, when not photosynthesizing the light ...

[oldmac]

I have about 9 plants and they are seedlings about 6 days old getting big now but i havent gave them a rest yet i was thinking about giving them about 6 hours of darkness tonite because they been going for 24/7... What do you guys think??? Is 24/7 to much for them and should i give them a resting period?????:jointsmile:

Hey jlve187,
There is no harm done to a plant by vegging at 24/0, 24/7.
I've used both 24/0 and 18/6 and it really is a personnel choice or what works best for you in your situation.

Hello ImageReaper,
Thank you so much for stating clearly that your answer was your opinion.

I think when people say that it needs a "rest" period, they are projecting thier human needs onto the plant. I also believed they needed a rest period, up to a few years ago when I took some botany classes at the local community college. Found out our beloved plant did not grow anything at night, not even roots.

Think about running a clonner....weak, blue biased light, 24 hours a day....to root cuttings. The interesting thing is, if you root cuttings using 12/12, it will work but root growth is much slower. If they laid down roots during the dark period the 12/12 should grow roots faster. (unless the plant is confused, not knowing to root or bloom?)

[jlve187]

Hey thanks helps me alot!!! i have another question though i have them in 8 oz plastic cups and i just looked on the bottom of the cups and i can see the roots they are touching the bottom and some of them are like becoming legnthy on the bottom ya kno....Should i transplant them into a bigger pot now or should i wait a few more days??? They are only 5 days old... I planted them on may 5th....around 3:30pm eastern time usa....Any replys would be great!!!:jointsmile:

[Rusty Trichome]

I think when people say that it needs a "rest" period, they are projecting thier human needs onto the plant. I also believed they needed a rest period, up to a few years ago when I took some botany classes at the local community college. Found out our beloved plant did not grow anything at night, not even roots.
What kind of plant did y'all grow? I'm guessing it wasn't even close to the cannabis species, with different native habits, growing conditions, nutrients and such. Galss container to monitor roots? C'mon...more info...

Although Image said it was his opinion, and you acknowledged his saying it was his opinion...I'm surprised to see you jump in with your opinion as if it were fact. This debate has raged on forever because there is ample suggestions for supporting both sides, and most of us that believe in the darkness period (me included) are, at the very least, mimicking the general conditions in nature, without risking developmental stress. (and a larger electricity bill) So without supporting documentation, your words will have be added to the 'darkness not necessary' category.

In other words...the next time you decide to slam someone else's opinion, how about showing your proof?

Too many cannabis fables...not nearly enough documentation.

[syde00]

but there's nowhere on the entire planet, that is fully lit 24 hours a day (except, maybe Las Vegas :D) ...



the artic circle actually gets 24 hours of light between june and august! good luck growing MJ in -40C weather though rofl.

[oldmac]

the artic circle actually gets 24 hours of light between june and august! good luck growing MJ in -40C weather though rofl.

Hi syde00,

Thanks for that, I was just going explain to ImageReaper the same thing. I stayed with a friend north of Fairbanks and in the summer at a certian point the sun comes up and then just geos round and round in the sky, till weeks later it finally sets a bit. Most disconcerting to people not use to it...imposible to tell north from south while looking at the sun.

[oldmac]

:
What kind of plant did y'all grow? I'm guessing it wasn't even close to the cannabis species, with different native habits, growing conditions, nutrients and such. Galss container to monitor roots? C'mon...more info...

Although Image said it was his opinion, and you acknowledged his saying it was his opinion...I'm surprised to see you jump in with your opinion as if it were fact. This debate has raged on forever because there is ample suggestions for supporting both sides, and most of us that believe in the darkness period (me included) are, at the very least, mimicking the general conditions in nature, without risking developmental stress. (and a larger electricity bill) So without supporting documentation, your words will have be added to the 'darkness not necessary' category.

In other words...the next time you decide to slam someone else's opinion, how about showing your proof?

Too many cannabis fables...not nearly enough documentation.

Hello Rusty,

First, let me appologize to you and IR, I was hoping to start a dialogue with him over certian inaccurrate statements he has made lately and where not proceeded by a opion disclaimer. I had seen you post a similar idea for the need for sleep, with the IMO....I was happy IR did it the same.

I was not trying to "slam" his opinion, that is really hyperbole on your part.
In fact I stated I held the same opinon right up to a few years ago, till I got some facts. But you are right, I should have labled it opinon so not to offend anyone who wanted to disagree with current scienitific thinking on this subject.

So here goes. It is my opinon, based on what I've been taught in a classroom, read in a botany textbook and later proved by real world experiments that marijuana, as a C3 plant has no need for a dark period or in human terms "rest" period, while in it's in VEGATIVE state. And they will grow roots without any dark period. In fact, while growing 24/0 for 24/7 it is quite "happy" to put it in human terms again. During the FLOWERING state a dark potoperiod is necessary.

Wish I was taking pics back then to doc the experiment. But the experiment was something I did after reading some BS on these boards last year. "you can't clone using 12/12". The debate went for awhile, to me it was stupid to argue since it is so easy to do an experiment, and that's what I did. Proved, at least to myself, you could clone at 12/12 if just took twice as long, or if I gave them the same number of days in the cloner, the 12/12 group had about 1/2 the amount of root mass. The only logical conclusion I could draw was they did not grow roots during the dark photoperiods ("sleepy time" to you). Try it, let me know how it works, for you.

BTW: In the college course I took we oviously did not grow any mj (wow, willing to make safe bets) but it was an often talked about often asked about plant. And the prof devoted one whole day to it (he told me after the class it's always the same, worlds most popular weed I guess)

In the future when I state something, I'll use the opinon disclaimer, even when I know it to be fact...like C3 plants need no dark photoperiod during veg.

Soooo speaking of cannabis fables, how about some proof for your opinon that marijuana needs a "rest period"? Maybe a couple of coffee breaks during the day would suffice. And since you feel strongly about thier need to rest, what are your thoughts on giving them two weeks vaction every year? :D

[Rusty Trichome]

Hello Rusty,I was not trying to "slam" his opinion, that is really hyperbole on your part.
In fact I stated I held the same opinon right up to a few years ago, till I got some facts. But you are right, I should have labled it opinon so not to offend anyone who wanted to disagree with current scienitific thinking on this subject.Hyperbole...? An obvious exaggeration...? Lol. You are slamming anyone's opinion that doesn't jive with yours. I could care less what the subject matter, if you are going to correct someone else's post, you damn well better be ready to back your words. Again...what facts? All I'm asking is for you to show some proof of your difinitive statements.


here goes. It is my opinon, based on what I've been taught in a classroom, read in a botany textbook and later proved by real world experiments that marijuana, as a C3 plant has no need for a dark period or in human terms "rest" period, while in it's in VEGATIVE state. And they will grow roots without any dark period. In fact, while growing 24/0 for 24/7 it is quite "happy" to put it in human terms again. During the FLOWERING state a dark potoperiod is necessary.
As I perviously stated, most of us believe that the rest period is helpful. Nobody said mandatory, as we all know cannabis does not need a dark period early in veg. But regardless, are you claiming that cannabis grows better (healthier, faster, stronger) on a 24/0 schedule in veg, than a 18/6 schedule? I'm not a believer, so go ahead and feel free to prove it.
In my experience, rooted clones and seedlings do better with a nightly dark period. I offer no proof, but I know what works for my cannabis plants, and share this insight with others.


In the future when I state something, I'll use the opinon disclaimer, even when I know it to be fact...like C3 plants need no dark photoperiod during veg. Damn good idea, as your "fact" is lacking proof. Especially if in regards to improved growth habits.


Soooo speaking of cannabis fables, how about some proof for your opinon that marijuana needs a "rest period"?
My proof...? There is none, which is why the debate continues unresolved.
Your last statements are childish at best. :thumbsup:

[purplekush989]

who has a bigger dick, rusty trichome or oldmac?

[oldmac]

Hey Rusty;

Try reading "Horticulture, Principlals and Practices" by George Arquaah.

Then if you would really like to discuss it and not debate it, come talk to me.

Otherwise, have a nice day.................

......'cause what would Willie do?????????

[oldmac]

who has a bigger dick, rusty trichome or oldmac?

Hey purplekush989,

If that is the criteria....I give up now.

I've said this before but it bares repeating now, I'm an old man and I equate things to Willie Nelson...........

one of the best "willieisms" is on his 75th birthday he announced: "It's offical, I've outlived my dick." and I'm older then Willie.

I do think Rusty is just looking to fight for some reason, I don't know why.

Shame he could not take a hint from StinkyAttic the other night....on Mother's day our "spiritual mother" made an appearence, and was not happy with what she saw. And basically was disappointed by all of our behavior, sort of left me with a feeling she was saying: I thought I had raised you all better then this.

Oh well, I'm sure Rusty is a fine individual and you know we do agree on a lot of things. It's ironic that this is over 24/0 vs 18/6 when in fact I use BOTH right now. In my home grow it's 18/6 and in my parterned grow we have been using 24/0 soon to change to 20/4. And I have no problem with those who use or bring thier beliefs about the plant to the table. If someone wants to believe thier plant needs to rest for whatever amount of time they think it is, thats ok too. It's just like believing in moon phases for planting or such, if it works for you then great use it. I will not critize it. I digress.

Hey purplekush, thanks for giving me an excuse to vent a little.

[Rusty Trichome]

I do think Rusty is just looking to fight for some reason, I don't know why.

Shame he could not take a hint from StinkyAttic the other night....on Mother's day our "spiritual mother" made an appearence, and was not happy with what she saw. And basically was disappointed by all of our behavior, sort of left me with a feeling she was saying: I thought I had raised you all better then this.
I'm kinda surprised you bringing stinkyattic into this. What's the matter...can't back your statement, so you'll attack elsewhere?
Stinky has other problems, and I'm quite certain she does not need you inserting words in her mouth to get her point across. Plus...I'm not here to impress her or you. I'm here to help all interested parties learn how to grow the best cannabis possible, without falling victim to old wives tales, etherial concepts, pyramid power, and factless theories. If she finds fault with my technique or insight...she'll let me know. The rest is simply personalities.

But it's funny you arguing a point you can't prove, and then you tell me I'm the one itching to fight. If fighting for the facts is is disappointing, then I guess you'll be disappointed quite often, as I am not one to say: "ok...it's not worth fighting over"...after the fight has been ongoing. You can't have it both ways. Either you can provide proof here, or not.

Everything in the natural world has a cause-and-effect.
Yes, cannabis can be grown on a 24/0 schedule. But is that optimal...? I argue that no...it is not best. And what kind of peripheral stressors does this add to the pants down the line? What what does it do to the plant's disease resistance? Dorught resistance? Oxygen exchange and outgassing? How much bulk is gained or lost? Will it lengthen or shotren the intrnode spacing? How about cell repair and development? How long before the genetics change, in the plant's attempts to accomodate the effects of a 24/0 schedule? How long till the thc/cbn/cbd ratios get too fucked-up to do us any good?
Link your proof, as I have no local library, and would love for you to point-out the docummented evidence that darkness does nothing for healthy vegetative cannabis growth. You can be the very first to provide this proof, in the history of cannabis forums. :thumbsup:

Also...I believe I heard you mention that the roots don't grow during the darkness...I'm assuming that by this, you mean that they do nothing during darkness. Is this the case? Anxiously awaiting your response. :jointsmile:

[jlve187]

Hey come on guys i didn't put this question up so that this could start agruments..Im sorry i did tho because its kind of my fault...But come on guys everyone has there own opinions ya know....I just don't want you guys arguing over something so stupid...Smoke a little and forget about it!!:jointsmile:

[filo6942]

But it's funny you arguing a point you can't prove, and then you tell me I'm the one itching to fight. If fighting for the facts is is disappointing, then I guess you'll be disappointed quite often, as I am not one to say: "ok...it's not worth fighting over"...after the fight has been ongoing. You can't have it both ways. Either you can provide proof here, or not.

Everything in the natural world has a cause-and-effect.
Yes, cannabis can be grown on a 24/0 schedule. But is that optimal...? I argue that no...it is not best. And what kind of peripheral stressors does this add to the pants down the line? What what does it do to the plant's disease resistance? Dorught resistance? Oxygen exchange and outgassing? How much bulk is gained or lost? Will it lengthen or shotren the intrnode spacing? How about cell repair and development? How long before the genetics change, in the plant's attempts to accomodate the effects of a 24/0 schedule? How long till the thc/cbn/cbd ratios get too fucked-up to do us any good?
Link your proof, as I have no local library, and would love for you to point-out the docummented evidence that darkness does nothing for healthy vegetative cannabis growth. You can be the very first to provide this proof, in the history of cannabis forums. :thumbsup:

Also...I believe I heard you mention that the roots don't grow during the darkness...I'm assuming that by this, you mean that they do nothing during darkness. Is this the case? Anxiously awaiting your response. :jointsmile:


If you want to blast by the veg phase use 24-0.

MJ is a c3 plant, it does not need darknes for veg!!! This has been proven over and over. I have grown plants side by side same strain, one with 24-0 and the other on 18-6. Guess which one grew faster and stronger? :jointsmile:


You may be wrong my friend.

[Rusty Trichome]

Sorry if I'm not impressed with your calims, but the last time I took someones statement on face value, I became a dad. (she wasn't on the pill)

Will lack of a dark period kill your plants? No. Is it the best treatment you can offer your ladies on their journey? In my opinion...no. And to me, it's not a technique I'd teach a newcomer unarmed to fight any potential stresses this induces in both short and long-term. I tried the technique a few times, and was unimpressed with root development and foliar growth. The plants without darkness looked runted and undernourished. Not nearly as healthy as what I usually grow, so yes...it does seem to change the plant physiology. (growth habits, the appearance of being healthy, size and structure of the leaves, internode spacing...) I offer no proof of my insight, as it is my opinion, developed after quite a few years of growing my meds. And like you, my hands are tied since there is no proof either way, that withholding darkness isn't a stressor. With the exception of nature, of course.

Ya know...this discussion would end real quick, were you two to back your statements with supporting documentation. But I'm done dicking with this thread, as you will continue to do what you want, and I will continue to enjoy my meds. Right or wrong...you have not convinced me of anything other than the fact that the debate continues.......:jointsmile:

[jlve187]

HEY GUYS FINALLY PUT A FEW PICS UP LET ME KNOW WHAT YOU GUYS THINK AND IF YOU HAVE ANY SUGGESTIONS THANKS:jointsmile:

[Italiano715]

Sorry if I'm not impressed with your calims, but the last time I took someones statement on face value, I became a dad. (she wasn't on the pill)

Will lack of a dark period kill your plants? No. Is it the best treatment you can offer your ladies on their journey? In my opinion...no. And to me, it's not a technique I'd teach a newcomer unarmed to fight any potential stresses this induces in both short and long-term. I tried the technique a few times, and was unimpressed with root development and foliar growth. The plants without darkness looked runted and undernourished. Not nearly as healthy as what I usually grow, so yes...it does seem to change the plant physiology. (growth habits, the appearance of being healthy, size and structure of the leaves, internode spacing...) I offer no proof of my insight, as it is my opinion, developed after quite a few years of growing my meds. And like you, my hands are tied since there is no proof either way, that withholding darkness isn't a stressor. With the exception of nature, of course.

Ya know...this discussion would end real quick, were you two to back your statements with supporting documentation. But I'm done dicking with this thread, as you will continue to do what you want, and I will continue to enjoy my meds. Right or wrong...you have not convinced me of anything other than the fact that the debate continues.......:jointsmile:


Rusty knows his shit! I'd definitely agree with 24/0 not having any substantial benefits. I enjoy my 18/6 and so do my plants, so that's is what I stick with. No plants outside in nature have lighting 24 hrs a day. That right there should tell you something! Anywho, I could really care less as long as they provide me with enough meds to keep me satisfied! :D

P.S. I tried to give you some +rep but it says, "You must spread some Reputation around before giving it to Rusty Trichome again." :D Sorry!

[filo6942]

Sorry if I'm not impressed with your calims, but the last time I took someones statement on face value, I became a dad. (she wasn't on the pill)

Will lack of a dark period kill your plants? No. Is it the best treatment you can offer your ladies on their journey? In my opinion...no. And to me, it's not a technique I'd teach a newcomer unarmed to fight any potential stresses this induces in both short and long-term. I tried the technique a few times, and was unimpressed with root development and foliar growth. The plants without darkness looked runted and undernourished. Not nearly as healthy as what I usually grow, so yes...it does seem to change the plant physiology. (growth habits, the appearance of being healthy, size and structure of the leaves, internode spacing...) I offer no proof of my insight, as it is my opinion, developed after quite a few years of growing my meds. And like you, my hands are tied since there is no proof either way, that withholding darkness isn't a stressor. With the exception of nature, of course.

Ya know...this discussion would end real quick, were you two to back your statements with supporting documentation. But I'm done dicking with this thread, as you will continue to do what you want, and I will continue to enjoy my meds. Right or wrong...you have not convinced me of anything other than the fact that the debate continues.......:jointsmile:



Ok, there are several books, even encyclopedias that explain a c3 plant grows as long as there is light for it to do so! I thought this was common knowledge, most plants on earth are c3.

Lets not forget where most of our country gets a HUGE ammount of its fruits and veggies from. Same place where the sun and calm weather allow for long days of growth. (San Juaquin Valley, CALIFORNIA)

If you want to grow tall, skinnier plants, then turn the lights off in veg.



I had to turn my lights off a couple times, but only because of heat, and since I added a fan so I can run the lights 24-0!!:stoned:

[Italiano715]

Same place where the sun and calm weather allow for long days of growth.

Not to argue, but you said ^^^^ and you said long days, which suggests there is still a night period. :D

Sorry, I'm reallllllllly :stoned: and I couldn't help myself!

[headshake]

that's funny becuase i've read that cannabis plants that grow under 24/0 grow anywhere from 25-33% faster. yet everyone that i have "talked" to says that that doesn't seem so accuate.

from wikipedia:

"Plants usually convert light into chemical energy with a photosynthetic efficiency of 3-6%. Actual plant's photosynthetic efficiency varies with the frequency of the light being converted, light intensity, temperature and proportion of CO2 in atmosphere, and can vary from 0.1% to 8%. By comparison, solar panels convert light into electric energy at a photosynthetic efficiency of approximately 6-20% for mass produced panels, and up to 41% in a research laboratory."

so it appears that there is a lot more that goes into it than just how much light is available. if your enviromental factors, assuming we have the same light, only allow you to hit a 3% efficiency than you can hit your plants with 24/0 and it wouldn't be as good as if you had better environmental factors and ran your lights 18/6.

you can't put shit in and get gold out.

also from wikipedia:

"The light-independent reactions are sometimes referred to as the dark reactions, though that term may be misleading as they do not actually require darkness to proceed. The term "light-independent" is used to emphasize that the reactions occur regardless of the amount of light present as long as the proper substrate compounds are available. Even this term can be criticized, however, as the availability of substrates in plants depends on photosynthesis, so the reactions cannot be said to be entirely "light-independent.""

so what that says is your plants don't REQUIRE a dark period. although this term is sligthly skiewed as it implies.

i'm not taking either side, because there is obviously more that goes into getting amazing plants than just hours of light that they receive.

there is a lot we don't know about cannabis plants, that will contiue to unfold as support for this wonderful herb continues to grow.

i love the passion though! you guys both rock!


-shake

[oldmac]

No plants outside in nature have lighting 24 hrs a day. That right there should tell you something! :D Sorry!

Dear Italiano715,

IMHO I think you are wrong about this. In Alaska you will find that the sun raises during the summer and then just goes round and round; and depending on how far north you are 24 hr sunlight lasts a few days to a few weeks, before the sun sets again. If you would like to see what it does to some C3 plants, just google "Alaska giant vegtables". (it also has a profound effects on humans)
That right there should tell you something. Sorry.

I accept your apology.

[oldmac]

Hey filo6942,

Thank you for speaking up on this subject. I was starting to think I was stuck in a black hole of ignorance.

Again, this is a topic that should not have to be argued about. You can find the answer in a book! I reccomended one that is great to have around, virtually every glasshouse operator I know has this book on his shelf.
"Horticulture, Principals and Practice" by George Arquaah

....or so easy to prove with a simple experiment.

I am not advocating any perticular light schedule to anyone, I happen to use BOTH at the present time! It is what works best for you, in your particular situation. BUT don't tell me or others that it is detrimental to the plant unless YOU CAN OFFER PROOF.

[oldmac]

Hey there jvle,

I'm am trully sorry about "hijacking " your thread. I realized last night that this was going nowhere fast and that even tho we where on topic, I knew it was not right to hold a school yard bitchin' party on your thread.

Sorry again.

BTW on you autoflower project, when you transplant from the cups to a pot, go for one big enough so you don't to transplant again. Their life is so quick, you don't want them slowing at all for anything.

[oldmac]

Hey Shake,

Thank's for the wiki answer. I believe when we deal with a plants cycle, "light-independent" reactions simple means "you don't need light to have it happen" and you are right that it could happen even with light present.

But keep in mind, while the science is in on "vegative" or in horticultural terms "immature" stage, the science is still not clear about the "flowering", or "mature prepoductive" stage. There is still a lot to learn from our beloved plant.
There has been some research that seem to suggest some flower brix conversions only take place in darkness. ( this may be the idea behind some peoples suggestion to put the plants in darkness 1 or more days before harvest.)

[headshake]

thanks oldmac! and i'm sorry for the wiki answers. i don't have near enough knowledge to speak first-hand, either way. the debate just sparked my perpetual curiousty (especially on this subject!) so i did a limited amount of research and felt that what was found contributed positively on the subject.

i am aware the sometimes my eagerness to chime in is not the best thing. i just can't help it!

so the way i look at it is, that because of the difference of opinion i was intrigued to go do some research on my own and learned a bunch (and peaked my curiosty and drive to find more information further)! so either way, regardless of point of view, fact or opinion, i learned somthing, and ya'll are pretty much directly responsible. so ya'll taught, i learned. isn't that the reason that we are all here?!

keep on posting and i'll keep on reading (you too rusty!)!


-shake

[Italiano715]

Originally posted by Xelatoth

I am a biology major currently taking a plant physiology course and I can tell you, at least according to my botanist professor, that plants will not benefit from the extra 6 hours of light in any meaningful way.

Their stomatic gas exchange occurs during the dark period and while they may induce this behavior during constant light anyhow, there is something they can NOT do in 24 hour light:

Their "dark" reactions!!!

A plant has 2 photosystems and both light and dark reactions!

The plant's electron transport chains will be active during light periods to "harvest" the light into chemical energy...

Now, this energy will be stored for use at night!

At night, the plant uses that stored energy for input into the Calivin Cycle!

The Calvin Cycle is the MOST IMPORTANT metabolic pathway in a plant and it finally can convert the chemical energy into useable sugars with the waste byproduct being O2.

Basically, 18/6 is really the only choice

*** 24/0 will allow for a forced Calvin Cycle, but the plant will need to expend MORE ATP and NAD+ to get the same singular glucose molecule... more work for same result = less vigor!

Fo' real.. let us put this to rest as Mother Nature is the best scientist there is!

Peace





This was posted by AlabamaJack in the Hot Pepper Forum. It was from a research experiment.

OPTIMAL PHOTOPERIODS
For tomato, best growth and yield were obtained under a photoperiod of 14 hours (Vézina et al., 1991; Demers et al., 1998b). Photoperiods longer than 14 h did not further increase yield. Photoperiods of 20 and 24 h can even decrease yield and caused leaf chlorosis (after 6 to 8 weeks) (Vézina et al., 1991; Demers et al., 1998b). Although long term use of a 17-h photoperiod does not increase growth and yield compared to 14 h, it might be interesting to extend the photoperiod to 17 h in order to increase total light provided to plants especially during the months with the lowest natural light levels (December-January). However, if a 17-h photoperiod is used, it is important that the dark period be uninterrupted, since splitting the dark period of 7 h in two short nights of 3.5 h (separated by a light period of 4 h) caused leaf chlorosis and decreased growth and yield (Vézina et al., 1991).

For sweet pepper, a 20 h-photoperiod was optimal for plant growth and productivity (Demers et al., 1998a). Yield under continuous light (24-h photoperiod) was equivalent to yield under photoperiods of 15 or 16 h (Costes et al., 1970; Demers et al., 1998a). Extension of the photoperiod from 15 or 16 h to 24 h decreased the average size of pepper fruits (Costes et al., 1970; Demers et al., 1998a).

Continuous light caused some leaf deformities (wrinkles) but no chlorosis in sweet pepper grown in greenhouses. Although long term use of continuous light is detrimental to tomato and pepper plants, tomato and sweet pepper plants can take advantage of the extra light energy provided by continuous lighting for a short period of time. Early vegetative growth and fruit production of tomato and pepper plants were generally improved under continuous light compared the 14-h photoperiod (Demers et al., 1998a, 1998b). However, after that initial period, plants under continuous light grew more slowly than plants exposed to 14-h photoperiod; so that tomato and pepper plant growth and yield under 14-h photoperiod were then equal to or higher than under continuous light at the end of the experiment.

Costes et al. (1970) also observed that continuous light improved the early performance (hastening of flowering and fruit set, increased early yield) of sweet pepper plants compared to a 15-h photoperiod. Therefore, it might be possible to use continuous light for a short period of time (5 to 7 weeks) to improve growth of tomato and sweet pepper, especially during the months with the lowest natural light levels (December and January). However, such a practice should be investigated in order to determine if short term use of continuous light might have residual negative effects on tomato and sweet pepper plants.

NEGATIVE EFFECTS OF LONG PHOTOPERIODS AND THE FACTORS INVOLVED IN THEIR DEVELOPMENT
Tomato and sweet pepper plants do not take advantage (no increase in yield) when grown under photoperiods longer than 14 h (tomato) or 20 h (pepper). Tomato plants, but not sweet pepper, develop leaf chlorosis under continuous light. In the next sections, we will examine the role of the carbon metabolism, pigments, light spectral quality and day/night temperature differential in the development of these negative effects of long photoperiods.

Carbon Metabolism
High starch and soluble sugar accumulations were observed in leaves of tomato plants grown under long photoperiods, and it was suggested that these accumulations could be related to the development of the leaf chlorosis (Bradley et al., 1985; Logendra et al., 1990; Dorais, 1992).

Studies on other species support the hypothesis of a relationship between leaf chlorosis development and starch and sugar accumulations. For example, continuous light caused increased leaf starch and hexose accumulations and leaf chlorosis of eggplants (Solanum melongena L.) (Murage et al., 1996). However, eggplants growing under continuous light but in a CO2-free atmosphere for 12 h per day accumulated less starch and hexoses, and did not develop leaf chlorosis.

Exposure of tomato and sweet pepper plants to continuous light resulted in increased foliar contents in starch in tomato and sweet pepper, in hexoses (glucose and fructose) in tomato and sucrose in sweet pepper (Dorais et al., 1996; Demers et al., 1998a, 1998b). However, the reduction of the number of fruits on the plants did not modify the pattern of accumulation of starch and sugars in leaves of tomato and sweet pepper plants exposed to photoperiods of 14 and 24 h (Demers et al., 1998a, 1998b). Moreover, the reduction of the number of fruits on the plants did not influence the severity nor the date of appearance of the foliar chlorosis in tomato plants grown under continuous light. This indicates that accumulations of starch and soluble sugars are not caused by a limiting sink capacity. If there is a relationship between the excessive starch and soluble sugar accumulations and the development of the negative effects (leaf chlorosis, decreased growth and productivity) of the long photoperiods on tomato and sweet pepper, it is most likely a limitation of the carbon metabolism at the leaf level which is responsible for these accumulations.

In tomato, the use of continuous light caused, in addition to the foliar chlorosis and increased foliar contents in starch and hexoses, a reduction of the photosynthesis rate and of the activity of the sucrose phosphate synthase (SPS) enzyme (Demers, 1998). These reductions in photosynthesis and of SPS activity occurred between 6th and 8th week
under continuous light, i.e. about at the same time as the foliar chlorosis appeared, while starch and hexoses contents in leaves increased during the first 4 weeks of the experiment.

Since the reduction of the SPS activity occurred after the increase in starch and hexoses, it is thus impossible that the reduction of the SPS activity is responsible for these accumulations. However, it is possible that the SPS activity in vivo is limiting, which would explain the hexose increase. This suggests the limiting step of the export of photosynthates is the synthesis of sucrose in tomato and would explain the absence of growth and the productivity increase under continuous light. Furthermore, the increased hexose levels in the cytoplasm, by a feedback effect, would limit the export of the triosephosphate (photosynthesis products) out of the chloroplast, which would then be redirected towards starch synthesis, thus explaining the increased starch contents.

Moreover, the increased accumulation of starch would generate, by a feedback effect, an overload of the Calvin cycle, which would gradually cause the observed decrease of the CO2 fixation rate. Are the starch accumulations responsible for the leaf chlorosis in tomato? It is possible that the overload imposed on the Calvin cycle (decreased photosynthesis) could limit the use of the reducing potential (ATP, NADPH) produced by the luminous phase of photosynthesis, thus causing an overload on the electron transport chain and the photo-oxidation of the chlorophylls (decrease in the leaf chlorophyll contents), and thus explaining the observed leaf foliar chlorosis. Transgenic tomato plants (in which a gene coding for the SPS enzyme was incorporated and overexpress this enzyme) could be used in future studies to test if accumulations of starch in leaves are responsible for the development of chlorosis observed in tomato plants exposed to continuous light. Transgenic tomato plants (overexpressing SPS) have higher photosynthesis rates and accumulate less starch and more sucrose than non-transformed
plants, especially under conditions of saturating light and CO2 (Galtier et al., 1993, 1995; Micallef et al., 1995). One can put forth the assumption that, under continuous light, leaf starch contents would be lower in transgenic plants than in normal plants. If this is the case, the reduction of the leaf starch content in transgenic plants should thus prevent the development of the leaf chlorosis, or at least decrease its severity.

In sweet pepper, the use of continuous light caused an increase in the leaf starch and sucrose contents, but did not affect leaf hexose contents, photosynthesis rates and SPS activity (Demers, 1998). The increased foliar contents in sucrose indicate that SPS activity in sweet pepper is not limiting as in tomato. Increased accumulation of starch in
sweet pepper plants exposed to continuous light would be explained by the fact that continuous light results in a longer period of time over which starch synthesis occur, but without overloading the starch synthesis pathway. Thus, starch accumulation in sweet pepper under continuous light would not be important enough to cause a reduction in CO2 fixation (no overload of the Calvin cycle). Increased leaf contents in sucrose suggest that sucrose export would be possibly limiting. In sweet pepper plants, the export rate of carbon (as sucrose) out of the leaf is constant, and the export rate would be limited at the level of the loading of sucrose in the phloem (Grange, 1985, 1987). This would explain why the growth and the productivity of the sweet pepper plants do not increase under continuous light.

Pigments
In growth chambers, continuous light caused leaf chlorosis, decreased photosynthesis rates, and reductions in leaf contents in pigments (chlorophyll a and b,
carotene, xanthophylls) in both tomato and sweet pepper plants (Demers, 1998). Leaf chlorosis, decreased photosynthesis rates and loss of pigments were more important and occurred earlier in tomato plants than in sweet pepper. Compared to sweet pepper plants, EPS ratio (epoxidation state of the pigments of the xanthophyll cycle) was lower in tomato, indicating a greater need for energy dissipation and a more important state of stress (caused by excessive light). Pigments such as carotene and xanthophylls (violaxanthin, antheraxanthin, zeaxanthin) play a significant role in the protection of the photosynthetic apparatus against damage that could be caused by an excess of light.

Carotene and xanthophyll levels were higher in sweet pepper plants than in tomato. Thus, sweet pepper has a better protection against the degradation of chlorophylls, which would explain why leaf chlorosis appeared later and were less severe in sweet pepper.

---- end copy/paste ------------
Leaving lights on 24/7 is OK and perhaps beneficial (not counting the cost of electricity) for no more than seven and maybe as few as five weeks and after that it is detrimental.

Mike

I know ^^^ isn't cannabis....well you get the point....healthier plants with a dark period.

1st quote link: 18/6 vs 24/0 (http://boards.cannabis.com/basic-growing/151905-18-6-vs-24-0-a.html)
2nd quote link: What are the Consequences of Leaving Lights on 24/7 (http://forums.gardenweb.com/forums/load/lights/msg0319125925834.html?37)

[Italiano715]

Photosynthesis

Photosynthesis is the process of converting light energy to chemical energy and storing it in the bonds of sugar. This process occurs in plants and some algae (Kingdom Protista). Plants need only light energy, CO2, and H2O to make sugar. The process of photosynthesis takes place in the chloroplasts, specifically using chlorophyll, the green pigment involved in photosynthesis.

[Leaf Cross-Section] Photosynthesis takes place primarily in plant leaves, and little to none occurs in stems, etc. The parts of a typical leaf include the upper and lower epidermis, the mesophyll, the vascular bundle(s) (veins), and the stomates. The upper and lower epidermal cells do not have chloroplasts, thus photosynthesis does not occur there. They serve primarily as protection for the rest of the leaf. The stomates are holes which occur primarily in the lower epidermis and are for air exchange: they let CO2 in and O2 out. The vascular bundles or veins in a leaf are part of the plant's transportation system, moving water and nutrients around the plant as needed. The mesophyll cells have chloroplasts and this is where photosynthesis occurs.

As you hopefully recall, the parts of a chloroplast include the outer and inner membranes, intermembrane space, stroma, and thylakoids stacked in grana. The chlorophyll is built into the membranes of the thylakoids.

Chlorophyll looks green because it absorbs red and blue light, making these colors unavailable to be seen by our eyes. It is the green light which is NOT absorbed that finally reaches our eyes, making chlorophyll appear green. However, it is the energy from the red and blue light that are absorbed that is, thereby, able to be used to do photosynthesis. The green light we can see is not/cannot be absorbed by the plant, and thus cannot be used to do photosynthesis.

The overall chemical reaction involved in photosynthesis is: 6CO2 + 6H2O (+ light energy) C6H12O6 + 6O2. This is the source of the O2 we breathe, and thus, a significant factor in the concerns about deforestation.


There are two parts to photosynthesis:

The light reaction happens in the thylakoid membrane and converts light energy to chemical energy. This chemical reaction must, therefore, take place in the light. Chlorophyll and several other pigments such as beta-carotene are organized in clusters in the thylakoid membrane and are involved in the light reaction. Each of these differently-colored pigments can absorb a slightly different color of light and pass its energy to the central chlorphyll molecule to do photosynthesis. The central part of the chemical structure of a chlorophyll molecule is a porphyrin ring, which consists of several fused rings of carbon and nitrogen with a magnesium ion in the center.

The energy harvested via the light reaction is stored by forming a chemical called ATP (adenosine triphosphate), a compound used by cells for energy storage. This chemical is made of the nucleotide adenine bonded to a ribose sugar, and that is bonded to three phosphate groups. This molecule is very similar to the building blocks for our DNA.

Structure of ATP

The dark reaction takes place in the stroma within the chloroplast, and converts CO2 to sugar. This reaction doesn't directly need light in order to occur, but it does need the products of the light reaction (ATP and another chemical called NADPH). The dark reaction involves a cycle called the Calvin cycle in which CO2 and energy from ATP are used to form sugar. Actually, notice that the first product of photosynthesis is a three-carbon compound called glyceraldehyde 3-phosphate. Almost immediately, two of these join to form a glucose molecule.

Most plants put CO2 directly into the Calvin cycle. Thus the first stable organic compound formed is the glyceraldehyde 3-phosphate. Since that molecule contains three carbon atoms, these plants are called C3 plants. For all plants, hot summer weather increases the amount of water that evaporates from the plant. Plants lessen the amount of water that evaporates by keeping their stomates closed during hot, dry weather. Unfortunately, this means that once the CO2 in their leaves reaches a low level, they must stop doing photosynthesis. Even if there is a tiny bit of CO2 left, the enzymes used to grab it and put it into the Calvin cycle just don't have enough CO2 to use. Typically the grass in our yards just turns brown and goes dormant. Some plants like crabgrass, corn, and sugar cane have a special modification to conserve water. These plants capture CO2 in a different way: they do an extra step first, before doing the Calvin cycle. These plants have a special enzyme that can work better, even at very low CO2 levels, to grab CO2 and turn it first into oxaloacetate, which contains four carbons. Thus, these plants are called C4 plants. The CO2 is then released from the oxaloacetate and put into the Calvin cycle. This is why crabgrass can stay green and keep growing when all the rest of your grass is dried up and brown.

There is yet another strategy to cope with very hot, dry, desert weather and conserve water. Some plants (for example, cacti and pineapple) that live in extremely hot, dry areas like deserts, can only safely open their stomates at night when the weather is cool. Thus, there is no chance for them to get the CO2 needed for the dark reaction during the daytime. At night when they can open their stomates and take in CO2, these plants incorporate the CO2 into various organic compounds to store it. In the daytime, when the light reaction is occurring and ATP is available (but the stomates must remain closed), they take the CO2 from these organic compounds and put it into the Calvin cycle. These plants are called CAM plants, which stands for crassulacean acid metabolism after the plant family, Crassulaceae (which includes the garden plant Sedum) where this process was first discovered.

Photosynthesis (http://biology.clc.uc.edu/Courses/bio104/photosyn.htm)

[Rusty Trichome]

^^^ Nice find.

Love the Wiki response...at least someone out there is trying...

In response to the 24hrs of light a day in Alaska...are you sure it's 24 hours of direct light? You sure it has all to do with the light, and not the temps...? What about UV and visible light refelcted off the moon? No correlation there...? There are signs from both sides of the aisle of the possibility of influence with and without dark or rest periods.

How Does Darkness Affect Plant Growth? | eHow.com (http://www.ehow.com/how-does_4567350_darkness-affect-plant-growth.html)

Cabbages grow big in Alaska when sunlight is abundant. The photosynthetic process occurs most readily when the sunlight available to the plant is the greatest. This is why plants in the tropics grow so large. They are near the equator where the sunlight is directly overhead much of the year. However, photosynthesis can occur in the dark. It does not occur as rapidly as during the daylight, but it is possible. If this were not the case, plants would shut down entirely every night when the sun went down.

Therefore, the periodic darkness of nighttime does not affect plant growth very much. In areas of the world, like Alaska, that experience seasonal increases in the length of daylight photosynthesis does make plants grow very large. Although Alaskan vegetable gardens are filled with plants that do well with cool temperatures and a short growing season (turnips and cabbage, for example), they tend to grow very large. This is because the sunlight hitting the gardens can do so for up to 20 hours a day.

Ecology Of The Night (http://www.muskokaheritage.org/ecology-night/speakers.asp)

Plants do not normally react strongly to the simple experience of darkness. However, autotrophic plants depend on light for their food, so darkness (the absence of light) influences their growth, and prolonged darkness is deadly. Certain unicellular algae (both marine and soil) avoid this problem in an interesting way. In light, they photosynthesize normally and make all the carbon compounds they need. But in darkness, they rapidly develop a powerful transport system that pumps external organic carbon compounds (particularly sugars) into their cells, providing an alternative source of energy and metabolites. The transport system is lost and photosynthesis begins when the light is turned on, and the rate of photosynthesis and transport may vary inversely with the light intensity. This mechanism provides a strong competitive advantage for these organisms.
The periodicity and duration of light and darkness is powerfully important in the development of many plants. The measurement by plants of light/dark periodicity enables them to fit their growth patterns to the seasons, and the duration of periodic darkness is critical for the onset of flowering in many higher plants. Thus, relatively strong light pollution during the night (as from street or flood lights) may seriously disturb the normal growth, development, flowering and senescence patterns of sensitive plants.
...
In general, plants are not usually much affected by the absence of absolute darkness at night, that is, by light pollution. Bright illumination at night may affect the flowering of sensitive plants, and other aspects of growth and development behaviour, including maturation and senili-ty, may be affected. But lower levels of light pollution, which might affect animal behaviour or astronomical observation, seldom affect plants in any significant way. Plants cannot be likened to the canaries in coal mines as indicators of excessive levels of pollution.

[oldmac]

[quote=Italiano715]Photosynthesis (http://biology.clc.uc.edu/Courses/bio104/photosyn.htm)[/QUOTE

To whom it may concern;

The point that I have made continually here, is this use of 24 hr photoperiod is for a "immature phase plant" or in terms we are all familar VEGATIVE state.
Most of these papers deal withe the entire life cycle of the plant, including "mature phase" we know as Flowering. IMHO a plant needs a dark photoperiod of at least some duration during this time. But not when it is in VEGATIVE state.

This is an excert of the above clip/paste:

>"Costes et al (1970) also obsevered that continuous light improved the early performance (hastening of flowering and fruit set, increased early yield) of sweet pepper plants compared to the 15hr photoperiod. Therfore it might be possible to use continuous light for a short period of time (5-7wks) to imrove growth of tomatoes and sweet pepper, especially during the months of lowest natural light levels (Dec/Jan). However such a practice should be investigated in order to determine if short term use of continuous light has residual effects on tomato and sweet pepperplants."<

At least I have you all looking and reading, next we need to work on our reading comprehension.

There are even more recent studies, and all seem to indicate the same thing, I can only conclude that it is not only NOT harmfull to use 24/0 for vegative growth, it seems to INCREASE growth.

OK Rusty, you did not want to read up on this, but Ital at least did. You did not want to accept any proof I had to offer, what about above? Italian715 is the source of this and he's trying to support your position.

Now with all this said plus all the additional rhetoric, I need to say this to you; I have no problem at all with your using 18/6 (I use it too) or if you want to say you have a feeling that your plants need a rest or that you think they do better that way, fine. I previously mentioned the human tendicy to "humanize" our plants, project our feelings and needs onto them. I realized I do it too, just last night a couple of minutes past 8:00 when my bloom room lights came on, I walked in to check on my girls with "good morning ladies how are you all doing!". Yup, I talk to my plants and somehow I think they like it. No science, no studies, but I really think they do better when I talk to them..... go figure.

This topic and others like it could be great to discuss, if you and I and others here could get less emotional and personnel with our debates and try to hold discussions instead. I'm willing to try and do better in the future.

[Italiano715]

If you would have realized, I just put in some quotes with no mention about the earlier debate. I read what headshake wrote and did research on it myself and found out the same thing. I merely put it out there for everybody's knowledge when coming across this thread. It's obvious everyone has there own opinion on the subject and I could care less what is better because I don't change mine even after reading all this. It's just something I found after further investigating and shared it with everyone to read. They were quotes from someone other than I and from a biology site.

P.S. Oldmac, relax and remember to stay away from the red pill (matrix) it's making you cranky!:D

[oldmac]

Hey there Italiano715,

I thought what you posted was very good. At least it contained reference to Costes et al's 1970 studies, which I had read before awhile ago. A whole lot of the info regarding photoperiods in regards to growing look at the complete growth cycle of a plant; but as you can see it my be an advantage at some points in a plants life and determental at others. BTW, subsequent studies to Costes et al's, has showed there is no harmfull residual effect (to tomato or sweet peppers plants) using 24/0 for short terms during vegative growth.

Yo' Headshake,

Don't be sorry about using Wiki, it's not a bad place to start with anything, just need to have a salt shaker handy so you can read thier stuff with a grain of salt. Everybody needs to understant that we really don't know everything about our beloved and sacred weed. It really is only in the last 20 years or so that science has figured out where the THC is located in the plant! Read older botany books (40+yrs old) and you'd think THC was in the leaves, stalks and branches. We've come a long way in a short time.

Oh, btw Italiano at 79 years of age I don't have much patience left and I use that as an excuse for why I'm so cranky. Besides, at my age it's one of the few things I'm still good at!

[headshake]

thanks again oldmac! i'm just a new macbook i guess, lol. i understand your points about the wiki. and i am aware that it is not fact by any stretch of the imagination, but nor is everything printed in a book either (not saying you agree to such rubbish, just a generalized statement).

and yes, i have TONS more things to learn, books and studies to read and experience to gain......and then some! i'm just happy that i have found something that peaks my interest so, with brilliant people to share it with and learn from!

i truly do thank you guys and everyone else that is a member of this forum because ya'll fuel my passion for this plant of ours (and botany in general). this is exactly why i like to call this place "home" (minus the bickering)!

"you must spread some reputation around......"


-shake

[Rusty Trichome]

Hey there Italiano715,
Everybody needs to understant that we really don't know everything about our beloved and sacred weed. Amen. Makes me wonder about the future of cannabis genetics, though. Are too many wives tales or improper breeding techniques degrading the cannabis genetics? Vanilluna, for instance...a varrigated cannabis?Vanilluna (http://www.icmag.com/ic/showthread.php?t=94684)) (links to external site)


Oh, btw Italiano at 79 years of age I don't have much patience left and I use that as an excuse for why I'm so cranky. Besides, at my age it's one of the few things I'm still good at!
Used to be, folks respected their elders. Now they use us for target practice, and wonder why we're cranky. :jointsmile:

[Rusty Trichome]

To whom it may concern;
including "mature phase" we know as Flowering. IMHO a plant needs a dark photoperiod of at least some duration during this time. But not when it is in VEGATIVE state. Sorry, but I'm not one to jump to conclusions just because there is a lack of specific "immature stage" papers involving side-by-side comparisons of the two techniques.


OK Rusty, you did not want to read up on this, but Ital at least did.
I beg your fucking pardon...? I've been reading up on this shit for years, and have found nothing saying that 24 hours of daylight is an acceptable long-term (months, years, longer...) strategy of keeping cannabis genetics pure. There is nothing available to date that shows effects, such as genetic changes, (or not) nutritional changes (or not) and resultant developmental differences, (or not) size and structure of the flowers, (buds) psychotropic effects from a different plant-growth strategy...none of which is covered in the above-cited work. You are really trying to tell me that a cause (no darkness) has no effect? Interesting concept, as everything has a cause and effect. Would be quite a development were all those that use 24/0 schedule had their strains turn autoflower on 'em sometime dowwn the line, since darkness "wasn't necessary".

I am curious what latent changes happen when you start fooling with overclocking a plants metabolic processes, but not curious enough to consider an unresolved technique as completely safe for my cannabis. Were we talking gourds or lettuce, I would care-less about it's genetic responses, but some of us actually prefer not to fall for old wives tales, snake oil, or any other questionable technique. Not at all against trying something new, but not at the expense of risking the genetics of the only meds I take for my ailment.


I previously mentioned the human tendicy to "humanize" our plants, project our feelings and needs onto them. Well, I guess that's the difference in our approaches. You try to keep from treating them like humans, I try to treat them like the medicinal plant that they are, and am not willing to take unnecessary risks because some old fart pretends that lack of pheno-specific evidence is to be assumed to be fact.


This topic and others like it could be great to discuss, if you and I and others here could get less emotional and personnel with our debates and try to hold discussions instead. I'm willing to try and do better in the future.

OK Rusty, you did not want to read up on this, but Ital at least did. Yeah. Sure. Whatever.

[FakeBoobsRule]

What is with all the hostility in this thread? Everyone what the hell is going on?

I've been looking back through a lot of posts both in this thread and in other threads and I'm just sitting here shaking my head.

It looks like there are some people who get offended in one thread and then decide to hold onto that and carry it over to other threads and to other members. It seems that there are others who get offended by one member and they hold a grudge and they just wait till a moment comes along where they can lay into them. I don't know maybe I'm missing something.

If someone atatcks you or flames you or calls you names or is questionable in any way, don't respond in turn, use the report key. It's really simple instead of going back and forth back and forth back and forth.

Yes, StinkyAttic isn't around as much and this was her area of expertise and she spent a lot of time in these sections. I have been making an attempt to read more of the posts in these sections but there is no excuse for this.

For the last time, if someone launches a warning shot across your bow, you don't return fire. Use the report key. The back and forth is just so unbelievably immature and a waste of bandwidth.

I am not addressing one person. I am addressing everyone.

[denialisback]

Hey jlve187,
There is no harm done to a plant by vegging at 24/0, 24/7.
I've used both 24/0 and 18/6 and it really is a personnel choice or what works best for you in your situation.

Hello ImageReaper,
Thank you so much for stating clearly that your answer was your opinion.

I think when people say that it needs a "rest" period, they are projecting thier human needs onto the plant. I also believed they needed a rest period, up to a few years ago when I took some botany classes at the local community college. Found out our beloved plant did not grow anything at night, not even roots.

Think about running a clonner....weak, blue biased light, 24 hours a day....to root cuttings. The interesting thing is, if you root cuttings using 12/12, it will work but root growth is much slower. If they laid down roots during the dark period the 12/12 should grow roots faster. (unless the plant is confused, not knowing to root or bloom?)

well actually its simpler than that. Constant light and unnaturally forced photosynthesis stresses plants, they aren't really genetically designed for it ;)

Still, some plants are hardy and can take it. :)

peace,
Denial

[metalhead419]

I had it explained to me by someone who actually tried both ways with cannabis and these were his results. Dont really remember word for word how it went, but it was something like it doesnt really matter either way. On a 24 hour schedule your plants will actually grow slower, but since they have an extra 6 hours of light compared to an 18/6 schedule in the long run your plants will grow bigger. Something like 25% more light, but only 15% more growth. So if your in a big f'in hurry for some reason, use 24/0, if not, 18/6 is just fine. In my opinion my plants look happier under 18 hours light than 24, i have tried both ways also. I also think, just my opinion, but i think its more efficient to use 18/6. Maximum plant growth for the amount of light, im all about efficiency in the growroom.

[EnhAnceD]

Im curious to know if you havent completly seeled off your grow room, if there is a tad bit of light, and i mean a bit, theres 2 cracks i just havent sealed, and really there is nearly no light from 12am to 6am which is my dark times. Im on day 5, should I hurry to seal those cracks?

[oldmac]

Im curious to know if you havent completly seeled off your grow room, if there is a tad bit of light, and i mean a bit, theres 2 cracks i just havent sealed, and really there is nearly no light from 12am to 6am which is my dark times. Im on day 5, should I hurry to seal those cracks?

YES, don't take any chances.

[headshake]

i concur. i think i just found a ball on two of my ladies! i'm not positive, but i'm pretty damn sure!


-shake

[EnhAnceD]

Done. I cant see any light from the outside, and if I didnt have all that crap in there I would be able to check inside. Would you maybe suggest haning a sheet over the door, or even inside the door just to be super safe.

[garbageman]

hey im new...just thought this to be an interesting thread, ill chime in my 2 cents.

i was told (and this goes with some of the previously posted info) that the plants store energy to use at night kinda like a battery. i was also told that they metabolize this energy faster and it only takes about 2 hours to use up the majority of it.

no proof. dont even remember who told it to me (for all i know my brain made it up). but its back there in my memory regardless....hope it helps.


as for drawing any conclusions, id say for plant growth the difference is trivial. its more which cycle best suites your situation...i remember one grow a while back i had everything i needed but a timer, and i couldnt get ahold of one for the life of me, so i went ahead with 24/0 since i didnt have a choice.(id rather let the plants adapt than trust myself to do it for them) i think its been proven that either way the plant fully adapts. if there were a difinitive answer/experiment proving it we wouldnt be having this discussion!

however, i do understand what oldmac is saying about humanizing our plants. the human learning process involves in one way or another direct comparisons to ourselves, and this works more or less for all living things.....except plants. theres only 2 kinds of cell structures plant and animal. so when saying a plant "needs to rest" (which is the arguement i always get from my dad) you have to at least broach the idea that they dont. since they are the only organic thing that isnt built like us on a molecular level, we can never really know.

stepping back into the animal kingdom where creatures have at least the same cell structure as humans, we see that rest cycles are a necessity and it varies from creature to creature, for instance some animals hibernate for long periods of time, others take many short naps. however animals have minds, and can make decisions (even if based on instanct). plants do not have any mind that we know of and are based more on reactions.

my point (and this isnt directed at anybody...excpet maybe my dad) is that if the dark cycle plays any role, its simply another phase or part of the reaction. "Rest" infer's that some kind of conscious effort was made. plants dont get tired. they simply react, be it efficiently or adversley. this includes adaptation.

damn i started rambling again....sorry. in any case you all rock for trying to find the answer :thumbsup::thumbsup: lol the pioneers of Operation: Plantation Nation. :rastasmoke:

[robwalker]

very informative.

[gypski]

Damn what a read!!! Now my :twocents::D Using a current event, a young seedling, not quite out of its seed shell was growing a root in the papertowel, and me being in a hurry, put it in a starter plug with the emerging seed just below the surface. Then next morning, I put it along with some others already with their first leaves and first true leave beginning to appear, out in the direct sunlight.

Being an impatient SOB right now, I decided to help the little bugger out and deftly removed the seed shell. The cotoldyl leaves were folded over and still closed tight as a nun's you know what!!! :stoned: And quite yellow in color and the temperature was rising fast. So, for the past two days I've been watching the little sucker and its going like gang busters. Its started it's first set of true leaves and tomorrow they will be that much bigger. The high temps have been in the very high 80s. Its gotten two nice night's rests outside with the temps in the high 50s. And dew coveres them all in the morning. I think that this proves that the cannabis plant has such a level of survivability anything is possible under any given set of conditions. And, the rest of my legal medical quota is doing much better outside in the natural light then the florescent I was using to get them rooting. I hoping for a good yield outdoors with free energy since the economy has me scraping by.

And, they seem to grow much better and happier as a group. It surely must be a social plant not liking to be alone!!! :jointsmile: :twocents:

[dukesdean]

I have about 9 plants and they are seedlings about 6 days old getting big now but i havent gave them a rest yet i was thinking about giving them about 6 hours of darkness tonite because they been going for 24/7... What do you guys think??? Is 24/7 to much for them and should i give them a resting period?????:jointsmile:

Give them a few hours of darkness. For many reasons, and facts.

[uneeeuh]

i got a quick question about the lights in my area...my friends growin in the outside but just figured that first frost is nov.28 and daylight savings is on nov.4,..(so the night will be longer)...that means i got like 3.5 weeks for flowering..i dont know if this will be long enough.is it ok to flower a bit past first frost or will the cold kill them..it gets hella cold in the desert