• [VEG] 18/6 vs 24/0

Discussion in 'Growing Marijuana Indoors' started by SproutDoubts, Dec 20, 2010.

  1. Ok, so Im quite new. I see various things on timers when it says how much time to put the lights on with little sprouts.

    I keep them on 24 except last light I passed out with them all under 1 single regular bulb houselight, maybe 60w. Much less than the 3 14w cfls and the one 23w cfl I have in the box.

    They certainly grew maybe a cm last night under that light but was it only because they were looking for the light they are used to having?

    Also I am using 3 5000k and one 6500k. These are the right range for the sprouts.

    Basiclaly I am wondering, 18/6 makes them grow taller but does that benifet at all if I am using a micro box?
     
  2. under CFL I'd do 24/0, with HID do 18/6.. save the 6h of electricity, Ive switched back and forth between 24/0 18/6 with HID and have not seen any extra growth from the extra 6h light. Under CFL the plant always seems to need more lumens, and since ur not using alot of energy no reason not to keep it on all the time.
     
  3. #3 motorheed, Dec 21, 2010
    Last edited by a moderator: Dec 21, 2010
    plants at this stage dont need a dark period as they are a c3 plant;)


    here ya go;

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    I found this useful-

    "It's been established for many many many years now that cannabis is a C3 plant. It does not need a dark period.

    C3 plants gather CO2 only during the light period when they are photosynthesizing. As long as the light is on, C3 plants gather and use CO2 for photosynthesis.

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

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

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

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

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

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

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

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

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

    The 18/6 photoperiod expels 3/4 the amount of light that a 24/0 photoperiod does. Although this does not mean that a plant produces 1/4 less leaves,branches and nodes under the 18/6 photoperiod, it certainly does show the correlation between light and cannabis growth. As we have said already, cannabis is a light demanding plant. There are no problems associated with 24/0 and although some have attributed cannabis sexual dysfunction (the hermaphrodite conditon) to 18/6 photoperiod these problems are actually the result of heat stress.

    A 24/0 photoperiod requires that your grow room temperature be kept well monitored. The 18/6 option is cheaper to run. You use a quarter less electricity and this will have an impact on your electricity bill. Also the 18/6 photoperiod will generally extend the bulb's lifespan. During the 6 hours of darkness the grow room is allowed to cool down for this period but a well maintained good grow room setup should not require a cooling down period.

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

    Sooo what light cycle do you use? And why?
     

  4. :hello::hello::hello::hello::hello::hello::hello:

    Thanks
     

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