Vegging Light Cycles - 24/7?

Discussion in 'Growing Marijuana Indoors' started by deluxed, Feb 7, 2010.

  1. Ok, first post, so what's up everybody. I used the search feature for a while so hopefully this isn't a double post but here we go -

    This is my first grow. I've got less than 10 plants - got them as clones and had them starting under a T5 fluorescent set-up for about 10 days. 24/7 light of course.

    Now...I ran across a free 430w HPS, and I know of course that MH is the way to go for vegging, but this is my first grow, it's a small operation, and this thing showed up free with a ballast etc...

    So for the past 10 days I've had them vegging under the 430W HPS. This has been on 24/7.

    To bring my question to a point - Is it doing the plants actual harm by having the HPS on 24/7? I've read that the normal vegging light cycle is 18/6. If I keep it on 24/7, is this maximizing growth and flowering potential? Or is it harming them?
    Lastly, a question regarding darkness/natural lighting -
    I've read that to get the plants to flower properly, you need absolute, absolute darkness (during the 12/12 cycle). Is this as key during the vegging cycle? Can there be natural lighting from the room/windows, or do I need to completely shut off my closet to be pitch black during the 6 hrs. off?

    other specs:
    strains are GDP and Purple Kush
    light clearance is about 18-20"
    plants are right about 15-17" currently


    Thanks if you can help.
     
  2. The debate between 24/7 and 18/6 is a long and heated one. The only real conclusion that I think both sides can agree on is that neither will "harm" your plants. Most feel that the plant needs time in the dark to rest... blah blah blah. I do both depending and I've never seen a major difference. The only harm of having the HPS on 24/7 is to your bank account via your electric bill ;).

    As far as light leaks they are incredibly important. They aren't as important during veg because the plant just sees it as a very week light, and you aren't actually confusing the hormones. During 12/12 though if you have light leaks you will cause serious problems. It's best to figure out where the light leaks are coming from and fix them during veg, than worry about them during flowering.


    One last thing to add that is off topic... 10 plants under one 400 watt light is wayyy too many. You want to figure about 100 watts / plant. Right now you're at 40 watts / plant, which is fine for vegging, but not nearly good enough for flowering. You either need to buy more lights, or keep some of your plants for mums and maybe throw them into the rotation later.

    There is always too an option of running your HPS 24/7 and just alternating the cycles. Group A of plants (which would be 5 plants) sits under the lights for 12 hours, once there 12 hours is up you put them in a dark place and let them sleep. Then you do the same thing with group B. It's just incredibly labor intensive, but a good way to make the most out of only having one light. No matter what you do you gotta decide something on flowering that many girls.
     
  3. #3 TheCareGiver, Feb 7, 2010
    Last edited by a moderator: Feb 7, 2010
    24/0 is fine for vegging the only reasons growers go to an 18/6 is cheaper and gives the plant a break at night, or even to cool off. But growing under a 24/0 light regimen they can grow an additional 35-45% faster than if they were under an 18/6.

    HPS is ok for vegging, Ideally you would want a MH to veg with as it is a wider spectrum and more blues for veg. [when switching between hps and mh, make sure you have the correct ballasts, just because it fits doesnt mean its the correct ballast.]

    For flowering, the HPS is the better of the two bulbs. It must be 12 on and 12 off, the dark period must always stay dark, no light whatsoever can be seen in the room when lights are off, if they do, they will remain vegging, or take much much longer to bud, and not flower correctly. Make sure your flower room is Light-Tight..
     
  4. Here is a quote from another thread I replied to:
    "As for light spectrum, just remember that you are trying to replicate the Sun. In natural outdoor grows the light in the fall changes to more of an orange when the days get shorter. For flowering, you want that orange spectrum. Personally I veg with T-5 fluorescent foxtures, but I know many ppl that have grown start to finish with a 2700K spectrum. Will it work? yes. Will you have better results with a mixed more full spectrum? Probably, because it would be closer to the actual sun."

    Here is the entire thread http://forum.grasscity.com/general-...ting-clones-beggining-my-12-12-flowering.html


    The thing with absolute darkness, which is most important during flowering, is to not stress and confuse your plant which can cause it to hermie itself. Hermaphrodites produce pollen (just like the males) and will create seeds. Any kind of white light that gets in will effect your plants. If you need to inspect them during their dark cycle I would suggest getting a green light or even green bulb flash light. The spectrum of the green light wont confuse them, nor will moonlight. Not exactly sure how that one works, but I know its because the moon emits a different spectrum and kind of light.
    Hope I helped some...
    Good Luck!!
     

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