Some of the best things happen during the dark

I have been reading some post that basically is pushing 24 hours of light. I needed to set the record straight. The common misconception is that everyone knows Marijuana needs light for photosynthesis but what most miss is they need darkness as well. We all have a hunch that plants need some sort of darkness, but we really do not know why. It's not that simple and it requires touching on a number of things to hone in on the whys and wherefores.


Our beloved marijuana plants are not as simple as some would make them out to be. They are far more complexed than “just a weed”. In the evolutionary chain if you match up a MJ plant with say an single cell organism, you would get the point quite clearly. Our plants are extremely complicated energy generating machines that function both in the sunlight and under the cover of darkness.


OK, here is where it gets a little complicated but bare with me; During daylight hours, our beloved Mary Jane takes in the light energy, some water and some air (CO2) to start the process known as photosynthesis and generates sugar and oxygen that is the building blocks of the cell energy and the release of CO2 into the atmosphere. However, carbon dioxide is generated in the dark side and is the source of carbon needed to maintain molecules. Without this dark period, it just does not produce the necessary amount of carbon to not only create molecules but to expell some of them.


People tend to forget that Cannabis is not a new plant. It is prehistoric in nature and brings with it a long history of very complexed evolution. This thing was around during dinosaurs (no wonder they were so happy) and acted totally different than they perform today. Heres how: during the days of the dinosaurs, the atmosphere was basically carbon dioxide rich environment. Through evolution, plants did us a favor and started converting this carbon dioxide into oxygen. Lucky for us.


As the world started changing, so did the Cannabis plant and plants in general as far as that goes. As the world changed in things like Temperature, Humidity, light conditions, cloud formations, daylight hours, extreme conditions such as heat and cold, and other environmental factors, the plants changed also. It is thought that the Cannabis plant started somewhere up in Tibet along the Himalayas but quickly moved South like so many snowbirds do to Arizona. As conditions changed, so did the neighborhood. Cannabis adapted, just like humans did. CO2 levels went down as the environment changed. So plants had to adapt to about 0.036% or 360 ppm.


So heres the deal: we are growing inside and trying to duplicate by artificial means the outdoors. So once we understand that we are merely duplicating natural conditions, we can then create better metabolic activity. I know I am going the long way around the track to get to a point, but I have to cover some basic ground to get to darkness. This is where it gets a little muddled. When the sun goes down, actual changes occur in a whole bunch of ways.


The first is the amount of lights wavelengths. We read tons of threads on Kelvin, different wavelengths and lights but really don't understand what these threads are really talking about. Look at it this way; when the sun sets, the angle of the light hitting the earth's atmosphere is tilted. It changes from bright daylight (white) blue spectrum (450 nm) to amber or red at sunset (650 nm) which is basically a shorter wavelength and thus carries with it more photon energy. That is why we need more red to flower (HPS during bud) and we need more white (Metal Halide) during veg stage. We are duplicating nature indoors. Basically humans developed in a similar way as we spend the day gathering food and expending energy. At night time, like cannabis, we metabolize this food to produce the energy to make new cells and repair the damaged ones we hurt during the day. We also use the night to produce very important enzymes and proteins and we wait for the sunrise to get to work or in a plants case, to start the day again photosynthesizing.


I know we are getting a little technical here and if you really want me to screw this thread up, let me introduce what the plant is really doing while it is sleeping is carrying out a cyclic process known as circadian rhythm from the Latin word meaning “approximately a day”. To take it one step further, all cells require metabolic energy in the form of what is called ATP or NADH. This energy is produced throughout the day and is the result of many biochemical processes, not just one. We all seem to concentrate on photosynthesis because we know it occurs during the daytime and we can understand that. Photosynthesis is the process of breaking down metabolic energy by using light energy (Produced during the day) to break apart water which generates O2, protons and electrons. Oxygen becomes the bus driver that transports all aerobic respiration and it is used to transport the electrons which in turn is used in the productions of those energy rich molecules known as ATP and NADH we talked about earlier.


So when all of this mixes together in photosynthesis, the Calvin cycle ( light) fixates or concentrates on CO2 to make what is called 3-Carbon sugars during this light cycle. Later during the darkness or “night cycle”, this 3-Carbon sugars are converted to 6-Carbon sugars such as glucose and fructose. Now the point should be clear and obvious. We need both the daylight for photosynthesis to occur and generate 3-Carbon sugars but we also need the darkness or night to finish the job and create 6-Carbon sugars to make glucose and fructose that is used to make cellular carbon or the bulk of ATP and NADH during aerobic respiration during the dark cycle. Does this make sense now?


Now we all read the Noob's desperate plea for help and how delicate the plant is. But it is really quite strong and we really have to fuck with it to screw things up. The cannabis will survive in a wide range of light, not just one, and under a wide range of temperatures. I am sometimes amused when I hear of temperatures being too high or humidity being out of range and I think of the tropics. Plants thrive there. And the last time I was in the tropics, it ain't no 72 degree's in an air-conditioned room. Temperature is however an important variable as it does effect humidity, dissolved gas concentrations, water stress, and is also an influence to the amount of water loss based on a ratio to carbon fixation, no laughing matter. The thing most noobs are yelling about is the leaf changes caused by light absorption , sugar formation and gas exchange. Back to the darkness, during the night the stomates in the leaves are closed to prevent loss of moisture and the need during sleep for gas absorption is not as great as during the day. During the day when demand is at it's peak, the stomata are wide open in the leaves as the demand for CO2 is at it's greatest. So when temperatures gets out of whack and rises, so does the loss of water through the very openings in the leaves stomata and the photosynthesis is maxed out at about 85 degree's but can handle a range from about 70 degrees up to about 95 degrees, a huge variable of temperature. So don't worry noobs, it can really be out of whack and still be viable.


Lets start this thread and I will add additional comments as we move along. If no one joins in the discussions, then I guess no one is interested and we will all just live in the darkness, no pun intended. ;-)

 

Plants do grow in all shades of colors except for green. Red however does play an important role in the regulation of the dark cycle. Red is the color or the sun setting and the sunrise and basically is used in dark room working around film. Cannabis can regulate temporally most biochemical processes by circadian rhythm, a form of the biological clock. Such a process regulates something as simple as leaf movement, flowering or even ripening response. The main protein responsible for this is called phytochrome.


Phytochrome comes from red light. That's how so many can go from veg all the way through using HPS (with its red spectrum) as opposed to using only Metal Halide and it's blue spectrum. So if you are faced with only one, I guess the way to go is HPS. Plants can also sense the movement of the sun in such as sun flowers follow it during the day but what they are following is the red spectrum with higher intensity at day break or sunset. Before I move away from this area, I want to touch on the biological clock for a moment as found in other parts of nature. That's the bird of Capistrano.


For years, most scientist could not figure out how the swallows would leave their breeding grounds in Mexico to fly north and arrive at precisely the same day each year on March 19th. The answer was in the light. The start of the internal clock of the swallows begins on the shortest day of the year, Winter Solstice. This year, it will begin on December 21st, 2009 at 12:47 PM eastern standard time. By placing a hood over certain swallows, they could delay the start of their flight to Capistrano by exactly the number of days that the hood was placed over the birds. So darkness does play an important role on not only the cannabis, but other forms of nature such as birds. I am sure you have grown for years with 24 hours of continual light, but it crosses my mind just how much better would your yield be if you possessed an open mind and looked at the lessons of Nature instead of knowing it all. Sometimes duplicating nature is indeed improving upon it by creating a “perfect environment”


I have read Frank, Rosenthal and of course Cervantes as well as some of the great Botanist of all time and if you look closely, they will all say that darkness certainly has an effect and the basic switching to 12/12 is mandatory to bring bud into flowering.


All I offer on this thread is a basic belief that 100% light during veg is not the end all, final answer to all of your problems. It may be what is creating some of them. I believe that cannabis does improve by getting a little rest. Many have successfully operated at 24/7 as many have also successfully grown at 20/4 as well as 18/6 and of course we all know what 12/12 does. So if this thread helps you in anyway grow a better crop, then I am all for it. If this thread opens up a discussion on possibly improvements to grow, well, I am all for that also.

 

I guess I should also quote some of my sources for this thread;

Vince-Prue, D. 1986. The duration of light and photoperiodic responses. Photomorphogenesis in Plants. Martinus Nijhoff, Dordrecht, Netherlands.

Wiskich, J.T., Dry, I.B. 1985. The tricarboxylic acid cycle in plant mitochondria: Its operation and regulation. Higher Plant Cell Respiration. Vol 18: 281-313. Springer, Berlin.

Zeiger, E., Farquhar, G., and Cowan, I. 1987. Stomatal Function. Stanford University Press,Stanford, CA.

Cervantes, Jorge. 2006. Marijuana Horticulture, Van Patton Publishing, Vancouver, WA

 

I think there are as many different ways to grow as there are growers. Hydroponics did not make much headway until the fifties and then only limited. Someone had to think up Deep Water Culture as well as Ebb and Flow, NFT as well as many combinations of "all of the above". Many ways work for many different people and I certainly do not wish to come across as "my way is the only right way". That was the purpose of this thread was to invoke a response and hopefully a meaningful discussion.

There are some out there that are swearing by LED lights and I believe there is a lot of room for progress in that area but I am not about to switch from the tried and proven methods of my HPS and yes, I also switched from MH for veg to HPS three weeks after clone to Bud. I think it is a softer gentler way of bringing them to harvest but that is personal opinion not based on facts nor supported by scientific data. However, there is just too much out there in regards to scientific research that indicates veg a little bit longer, put em under a scrog and give em a rest. But not all agree with that and to them, I wish them well. They of course are entitled to their opinion and I hope it works out well for them.

Rosenthal, Green and Cervantes all have different ways of doing things. I think if you go out and do a survey of commercial growers in Holland, Canada and Northern California, you would find far more on a sixteen to Eighteen hour light cycle than you would ever find those running 24 straight. I would be very interested in this thread if others would post their light cycle and why?

 

To continue on with the reasons I feel it's best to give em a rest is in the area of Phytochrome which is triggered by red light spectrum (650 nm). A point to note however is it can be reversed by far red light (720 nm). I would tend to be a little careful with too far on the scale such as Infra red or far red and stick with the tried and proven lights such as HPS. That is why I am not so high on the LED stuff and feel that they could inadvertently mix the wrong color spectrum into the light combination and your plants would stop growing and you would not know why.

The phytochrome is why plants can sense the movement of the sun and have you ever noticed your plants leaning towards “the light”? Cannabis are grabbing whatever photons they can get, from any direction they can get it from and interrupting the dark cycle with light can dramatically alter its circadian rhythm as in the case of introducing light during the 12 hour darkness cycle of Budding. One note, Phytochrome has been noted to make a response in the blue spectrum (450 nm) which in my opinion is the reason you get a limited success out of MH during flowering. But again, if I had only one choice and could go with only one bulb, I would go with HPS.

Some have quoted in earlier post that continuous light effects the growth, quantity of harvest and other measures. I disagree. Cannabis energy metabolizing systems function on many different plains and on many different levels. A biochemical pathway can only proceed as fast as the rate limiting enzyme or substrate. The primary source for regulation is genetic, not 24 hours of light as an earlier poster quoted greg Green on. The thing I like most about Green is he tries to give you both sides of the argument but in the case of 24 hour light, I feel he is dead wrong.

Chloroplasts and mitochondria have their own genetic code that produce the enzymes needed for their respective process. The only way to up-regulate genetic expression is either through genetic engineering or producing more of these genes by making sure the plant has all its required nutrients to produce more new cells. Another mode of regulation is through the limiting pathway intermediate, as mentioned regarding CO2 supplementation where the limiting factor becomes the regeneration of ribulose-1,5-bisphosphate. Unfortunately, the regeneration of this substrate is also regulated by the electron transport chain.

Sometimes a limiting reactant can be artificially added to increase metabolic activity, as in the addition of amino acids, hormones and cofactors like trace vitamins and minerals. Ultimately, the major mode of regulation is environmental. Changes in water properties, nutrient availability, temperature, light duration and strength, humidity, and dissolved gas concentrations are big obstacles that need to be orchestrated to achieve maximal metabolic activity.

Now that I have pissed off the masses, let's hear what you have to say about 24 hours of lights.

 

I hope fencewalker does not unscribe, he keeps us honest. I have always felt that a "difference of opinion" is not only healthy, but wise. I have never learned anything in my life by being right all the time. It is only wihen I really make a mistake and someone calls me out on it, that I truly learn anything.

Civil is one thing, and I like that quote by Patrick Henry who basically said;
"I disagree with what you say, but I will fight to the death your right to say it." And then the English hung em ;-) The difference in this board from so many others is the "lack of flame wars" because basically, we all have a horse in the race or Dog in the Fight. We all have common interest and honestly, I know of no one who really doesn't want the other guy to succeed. I have seen so much patience with newbies who ask some really stupid questions and then it occurs to me that "the only stupid question is the one that is not asked" and I try to be a little more humble and remember my first grow in the sixties when we didn't have a clue as to what was going on. Man, if I told you some of the shit we did back then, no one would believe me.

In 1978, I built a Green House that was 120 feet long by 32 feet wide and planted 1,100 Tomato plants in gravel because I knew damned well what I would be growing inbetween those hummers the next crop. My holding tank was 8 feet by 8 feet by 8 feet and you rocket scientist out there can figure out how many gallons of water I was pumping three times a day for about a half hour. Back then, no one believed I could grow 1,100 plants in gravel, they said they would fall over. (I used tie downs and strings)

My crop has always grown better when I give em a chance to rest up a bit. Could be habbit, could be genetics, could be many things, but I honestly feel that without at least six hours of darkness, my plants are just not as healthy looking. With rest, they seem happy and I know this is not very scientific, but when a time clock fucks up and I miss turning off the lights by an hour or so, the next day my plants are "hung over".

One final note, Duplicating everything is now a priority with me. when I need one air pump, I install two. I have back up's for every system in the joint including timers now, fans and scrubbers. Everything. Good luck on your grow, if it works for you to grow with 24 hours of light during veg, by all means use it. If your plants seem healthier by giving them a rest, by all means do it. If you think you are right or you think you are wrong, you probably are....