Light Duration

Discussion in 'Growing Marijuana Indoors' started by ChaosSmashKill, May 11, 2003.

  1. I just planted my seed and was wondering how long I should keep the lights on at first.
  2. keep the lights on 24/7 for veg, and cut back to 12/12 when ready to flower...

  3. some go with 18/6 for veg and 12/12 for flowering

  4. 18/6 for veg is not a good idea. Unlike humans, plants dont need sleep. Once they have sprouted they photosynthesis as much as possible, so the more light offereed to them, the faster they grow. :) I would only 18/6 the last couple of days of veg so they can get used to a dark period before 12/12 flowering.
  5. Well you can't run a HPS 24/7 so you'll have to use 18/6...if only using flouros go with 24/7.
  6. why can't you run an HPS 24/7 for Veg? I did and I'm still not dead....

  7. im running and hps 24/ this a bad thing?
  8. the only reason NOT to run HPS 24/7 is because the lights need at least a 15 minute break each week to help maintain the life of the bulbs.
  9. If your changing bulbs every show(which you should) then it doesn't matter keeping them going 24\7.
  10. Well, if we are talking about a grow closet, IMHO, 18/6 is best. Heat is always a issue for me and the 6 hours helps keep the temp down alittle, I have mine off the hottest part of the day. also, it might not make a huge differance but it will help lower electric costs alittle. I have also read that running HPS 24/7 will decrease lumen output much quicker than 18/6.
  11. Im running

    75w HPS
    1 C flouro spiral 25w
    1 Flouro tube "trichromatic" earth spectrum 30w
    3 show n gro 40w flouro tubes

    I run them all 24/7..... although sometimes I turn off the
    3 show n gro, because they tend to have a higher heat output then other flourescants... dont know why..

    Ive had no problems doing this... been doing it for about 29 days.. today!

  12. I didn't know my answer would receive a response like that. The reason why someone would use 18/6 can be due to many reasons. I posted what I have done, which doesn't mean that's the only way something could be done. Its just my knowledge about the subject. By the way nice observation in pointing why 18/6 is bad. Some grow rooms as NikiDog pointed out, is hot since they are mostly a small box in a closed place or a closet. It always depend on ur own situation, plus how intelligent u r which sometimes decreases due to the inhaling of weed smoke. U should know how normal house fires are started and try to avoid those things that one should not do. A rest for the bulb is one thing to consider. When the lights are on, its burning the chemicles in that little bulb to eluminate. When its off these chemicals are sleeping/resting. One day this checmical will decrease in power and eventually malfunction or not function at all. As for the plants, I thought plants are like any other organizm hence needs a little bit rest to digest or stop the food producing glands from pure exhuastion. I might be wrong in thinking like this. Anyway, I will let u know how mine turns out.

    The Dude Abides!
  13. here's what i do.......i run my 400w HPS and my 150MH 24/0 for the veg stage, approx 30 days............the 150 helps speed the process up to help save my HPS bulb, but the diffrence between my HPS and MH and most others is that they are floodlights for companies, and are designed to run 24/0 indoors or outdoors, hence better to have indoors for less risk of for the plants, they can survive it for approx 30 days, i wouldn't do it if i was gonna say grow one to 2-3' and then trigger..........Peace out.........Sid
  14. Havent grown in about 8 years. Starting all over new place,equip,seeds,media, everything.
    This is my s.o.p:
    -When I first start, I like to run 20/4. Hps timmed. Standard stuff. Till 3 foot.
    Then i go down to 18/6 for around another foot of growth.
    Then full fledged 12/12 for flower to finish.
    Any thoughts, I'd appreciate the feedback back
  15. Anything from 16/8-24/0 will work.

    Ive used 24/0 for 40 years, and of course you will wear the bulb out faster at 24/0 vs 16/8. Its on 1/3 more, so it will wear out 1/3rd sooner.
    And of course they will grow faster on 24/0. Theyre on all the time.

    Also no need to taper from 20-18-12. Wont hurt but you lose 2 hours a day veg time. 60 hours... 2.5 days in a month. About 8%.

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