So is 24/7 light bad for your plants growth?
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mygirls
Medical Marijuana (MOD)
thats what im saying about 18/6 vers 24/0. busher plant i got that put out more nodes in turn more yield. your plant is going to be much better running 18/6in other words, yes, grow #4. i'm sure that the lighting cycle is the only thing that has changed to increase your yields....couldn't possibly be that your game is improving with experience....
Hey guys, I'm usually a lurker (thanks for all the info you guys provide, I use it well), but ya I am a very scientific minded person, so lets think about this. As has already been said photosynthesis occurs only while the plant is exposed to light. The Calvin cycle (sometimes misleadingly referred to as the dark cycle) is actually independent of light exposure. The Calvin cycle runs off of the products of the light driven reactions however (ATP and NADPH - basically the same energy that we get as humans from the breakdown of our food). Since the Calvin cycle is driven by these products of the light reactions, it can occur at nightor anytime for that matter, but it will only occur until it has used up all of the available ATP and NADPH. The Calvin cycle is responsible for producing Sucrose (the plants energy source), starch (its energy storage), and it produces amino and fatty acids that are used to further the growth of the plant. The light cycle will produce the ATP and NADPH a little faster than the Calvin cycle can use them (think evolution here, the plant developed outside where it recieves light from the sun, lots of energy, then the world spins and it is dark, and the Calvn cycle is running this entire time b/c the plant made lots of ATP AND NADPH b/c it was recieveing light from the sun not light from a mechanical light. Oh PS the calvin cycle also runs on CO2, in addition to the atp and nadph, which it gets from the environment. Anyway whoever was hypothesizing (sp?) about the getting 100% of the light was in a way correct, but if your growing indoors this really won't happen b/c the sun is much more powerful than even multiple 1000 watters. So without any type of lab experiments on this type of information I run 20/4 with a 400 w MH because I want to allow the Calvin cycle to catch up with the light reactions, b/c the calvin cycle also produces NADP+ (positive charge b/c it lost a hydrogen atom) and ADP + Pi (d stands for di or 2, T in ATP stands for tri). These calvin cycle byproducts then are used with light and water to recreate ATP and NADPH, so it is my opinion that a short dark timeperiod such as 4 hour or so would be beneficial to the plants growth, as it allows both the calvin cycle to catch up and create the plants neccessary sugars and etc., but it also replenishes the fuel for the light reactions to occur the next time the lights come back on. This is why I choose 4 hours because I have had good experience with it and feel that more darkness is just kind of a waste of production time, while less darkness might not be allowing the plant to grow at its fullest potential. I have excellent diagrams of these processes, but I don't know how to post them yet, so I'll be working on that one.
mygirls
Medical Marijuana (MOD)
in the past i have ran 24/0 the 1st 30 days in veg then switch to 18/6 the last 30 days in veg and willbe doing that again.
Ya, but what I'm saying is that you may want to try 20/4, 21/3, 22/2 or something like that. I feel like 6 hours of darkness is too much for a plant being fed by a mechanical light, and 0 hours of darkness is not enough to allow the calvin cycle to catch up with the light reactions.
Hayduke
Well-Known Member
I think it is strain dependent. I turned 3 strains hermie, near as I can tell it was from a long 24/0 unnatural light cycle. I was told this from an acquaintance who has grown for 15 years and the ONLY time he had this happen was under 24/0. Makes sense.
That being said, if they stretch (grow) in the dark...why would someone think they do not grow roots in the dark?
That being said, if they stretch (grow) in the dark...why would someone think they do not grow roots in the dark?
Think about growing as a buisness, you want the maximum yield, in the shortest amount of time, with the least amount of overhead. If you run 24/0 your lights and ballasts will wear out quicker because you don't allow them any time to cool down between uses and instead have them on for weeks or months at a time. Also you are not giving the plant a chance to use up its stores of NADPH and ATP, this results in sub-optimal growth and development. Similarly with 18/6 you run too long of a dark period, which doesn't hurt the equipment, but is an oppourtunity cost loss because you are not giving the plat enoughlight a day to reach its optimal growth. This results in taking a longer time to reach the same yield, so you are losing time in essence and as we all know time is money. These reasons are why I choose to run 20/4 and it works awesome.
All this being said however, personal experimentation is important to achieve maximal returns b/c marijuana grows differently and has different needs based on its individual genetics. So the basic ideas to remember from all of this is:
1. Having a little bit of a dark period is beneficial but don't make it too long or you are wasting time.
2. Chill on the message boards, we are all stoners tryin to grow weed the most effecient way possible, no name calling necessary. Be open to new information about the topic, knowledge gained from experience is important, but so is scientific knowledge of biology and chemistry.
All this being said however, personal experimentation is important to achieve maximal returns b/c marijuana grows differently and has different needs based on its individual genetics. So the basic ideas to remember from all of this is:
1. Having a little bit of a dark period is beneficial but don't make it too long or you are wasting time.
2. Chill on the message boards, we are all stoners tryin to grow weed the most effecient way possible, no name calling necessary. Be open to new information about the topic, knowledge gained from experience is important, but so is scientific knowledge of biology and chemistry.
They do grow in the dark because the calvin cycle is still producing sugar, startch, amino acids, an fatty acids in the dark. These components are what make the plant grow, and the plant will continue to grow in the dark as long as it has stores of ATP and NADPH remaining.I think it is strain dependent. I turned 3 strains hermie, near as I can tell it was from a long 24/0 unnatural light cycle. I was told this from an acquaintance who has grown for 15 years and the ONLY time he had this happen was under 24/0. Makes sense.
That being said, if they stretch (grow) in the dark...why would someone think they do not grow roots in the dark?
mygirls
Medical Marijuana (MOD)
witch is all pending on the amount of light,the kind of light.
Hayduke
Well-Known Member
Thanks for the science...I was about to go get Campbell's Sixth Edition...just did, and read a little about Calvin Cycle...just read a little more...And though I do not disagree that some dark is good, "The metabolic steps of the Calvin cycle are sometimes refered to as the dark reactions or light independant reactions, because none of the steps requires light directly. Nevertheless, the Calvin cycle in most plants occurs during daylight, for only then can the light reactions generate the NADPH and ATP spent in the reduction of CO2 to sugar" (and I read some science based stuff on optimum light cycles and they found that MJ photosynthesis slows to almost a halt after ~18-20 hours and benefits from a short rest. To maximize yeilds they ran the lights for some time (don't remember exactly...like 20, and then a short rest and lights on again...it was not based on 24 hour days, so the light schedule [time on/off] changed a litle everyday...not practical for most)
This post has taken a long time as I have been reading, writing and smoking. I will end here, but I believe I have the solution to why both sides are right...though most will not follow.
Edit: I just remembered...the test grow mentioned above also included lights on longer than 12 during flower and off for the needed 12...that is what messed up the 24hr day.
Hayduke
Well-Known Member
Hey dude, I just looked at you diagrams again of Photosynthesis, Calvin cycle, and non cyclic electron flow during the light reactions....those are test blanks..if you have electronic copies that have the reactions labeled and could replace the blanks, it would be helpful for those that will actually read all this mumbo-jumbo! Thanks dude!here are those diagrams. time to smoke haha too much science on saturday morning, haha hope i helped a little.
Hayduke
Well-Known Member
Well I tried to edit my last post and add the revelation of how both the 24/0 and the 18/6 folks are right, and my post vanished when I hit edit instead of save changes.
Anyhow: Photorespiration. robbing the Calvin cycle in hot bright dry conditions through Rubisco's affinity for O2 in the absence of CO2 and the resulting loss of carbon from the Calvin cycle. This is thought to be "evolutionary baggage" left over from the earlier atmosphere which was higher in CO2.
Here it is...If you use unnaturally high levels of CO2, the levels of CO2 within the leaves may not ever become depleted, even in times of closed stomata. That being said...those supplementing CO2 are usually using a dedicated A/C and often Hydro..both reducing stomata closure. This senario would favor 24/0.
If you do not supplement CO2 and fight temps with occaisonal trips into the 80's and use A/C only when absolutely necessary, 18/6 would reduce the amount of photorespiration, and would produce happier girlies, and better yields.
The effects of photorespiration are well studied in soybeans (another C3 plant) From Campbell "The environmental conditions that foster photorespiration are hot, dry, bright days--the conditions that cause stomata to close" Sounds like life under a 1000w fixed light!
Considering the relatively short veg time given by most growers, the fact that people get all upset over it is kinda comical
Anyhow: Photorespiration. robbing the Calvin cycle in hot bright dry conditions through Rubisco's affinity for O2 in the absence of CO2 and the resulting loss of carbon from the Calvin cycle. This is thought to be "evolutionary baggage" left over from the earlier atmosphere which was higher in CO2.
Here it is...If you use unnaturally high levels of CO2, the levels of CO2 within the leaves may not ever become depleted, even in times of closed stomata. That being said...those supplementing CO2 are usually using a dedicated A/C and often Hydro..both reducing stomata closure. This senario would favor 24/0.
If you do not supplement CO2 and fight temps with occaisonal trips into the 80's and use A/C only when absolutely necessary, 18/6 would reduce the amount of photorespiration, and would produce happier girlies, and better yields.
The effects of photorespiration are well studied in soybeans (another C3 plant) From Campbell "The environmental conditions that foster photorespiration are hot, dry, bright days--the conditions that cause stomata to close" Sounds like life under a 1000w fixed light!
Considering the relatively short veg time given by most growers, the fact that people get all upset over it is kinda comical
Oh, my bad just took them off of my biology slides, and I must have left the text behind. I will work on that now, but cool info about the non 24 hour grow cycle, I am very interested in reading about that, and after I attempt to put those slides up I will go searching for that. It makes sense that they need the break so maybe we should be aiming for something more like 20/1. Any timers that make that kind of thing easy?Hey dude, I just looked at you diagrams again of Photosynthesis, Calvin cycle, and non cyclic electron flow during the light reactions....those are test blanks..if you have electronic copies that have the reactions labeled and could replace the blanks, it would be helpful for those that will actually read all this mumbo-jumbo! Thanks dude!
Hayduke
Well-Known Member
Thanks dude. The one that I lost explained it better, but was wordy enough that most would have ignored anyway.
Yes, programmable timers. And then maybe a little night light bulb outside the grow, extension corded to the surge suppressor the light is plugged into, to show when lights are on and off.
mygirls
Medical Marijuana (MOD)
this is interesting and good, but here's my ? to you. now mind you i grew the same strain, same soil and nuts every ting was the same. on my 2nd grow running 24/0 yes i had a way taller plant 7ft tall and i got just over 5 oz a plant. now on my 4th grow running 18/6 yes my plant did not grow as tall only being 5 1/2 ft tall but now the bush it was and the yield i got off here. 415 grams and these are dry weights. now can u c my argument. all my proof from my experences are on youtube user name growingmeds.
i do belive i was saying this in a sence.Well I tried to edit my last post and add the revelation of how both the 24/0 and the 18/6 folks are right, and my post vanished when I hit edit instead of save changes.
Anyhow: Photorespiration. robbing the Calvin cycle in hot bright dry conditions through Rubisco's affinity for O2 in the absence of CO2 and the resulting loss of carbon from the Calvin cycle. This is thought to be "evolutionary baggage" left over from the earlier atmosphere which was higher in CO2.
Here it is...If you use unnaturally high levels of CO2, the levels of CO2 within the leaves may not ever become depleted, even in times of closed stomata. That being said...those supplementing CO2 are usually using a dedicated A/C and often Hydro..both reducing stomata closure. This senario would favor 24/0.
If you do not supplement CO2 and fight temps with occaisonal trips into the 80's and use A/C only when absolutely necessary, 18/6 would reduce the amount of photorespiration, and would produce happier girlies, and better yields.
The effects of photorespiration are well studied in soybeans (another C3 plant) From Campbell "The environmental conditions that foster photorespiration are hot, dry, bright days--the conditions that cause stomata to close" Sounds like life under a 1000w fixed light!
Considering the relatively short veg time given by most growers, the fact that people get all upset over it is kinda comical
Hayduke
Well-Known Member
I like all the quotes with the side by side grows...I think I read them elsewhere before?i do belive i was saying this in a sence.
Anyhow the size of your font is larger and bolder than earlier today...If I have offended you, it was not intentional, and if I was being redundant in my quoted post, I apologize...
Yes, but I think you need much less than 6 hours of darkness, for vegetative growing is the only thing I think you are still not getting from all of this.i do belive i was saying this in a sence.
Hayduke - Sorry this is a pretty high thought, but is your name duke, and everytime I read your name am I saying hi to you? I'm attaching my recreations of the slides, they're kinda sloppy but I did it in paint so it was kinda the best I could do with those blanks.
