Adding Mh To Flower

Discussion in 'Growing Marijuana Indoors' started by medicalneed, May 28, 2013.

  1. #1 medicalneed, May 28, 2013
    Last edited by a moderator: May 28, 2013
    My buddy has 2 extra lights sitting around that he can add to his current grow; a 400mh and a 1000mh.
    He currently has two 600w HPS lights in the flower room.

    Since he wants to reduce power, I suggested putting the 600's on a schedule of 11hrs each (offset so one starts first, one finishes) and the middle 400mh being 11hrs also (middle of light schedule).

    He believes that plants can't absorb more than 6hrs of blue light in flowering though, so it's pointless.
    His idea uses about the same power, but with a lot more blue light and a little less red:
    Left side 600HPS --- 12am-10am (10hrs)
    Middle 1000MH    --- 3am - 9am   (6hrs)
    Right  600HPS     --- 2am - 12pm (10hrs)
    The lights are set up from East to West, with the blue light being in the middle and all lights pretty close because it's only covering 2 plants deep by 5 plants long (10 total). He's medical so can't do anymore than 15 total and usually has a few in veg to be perpetual. Veg room just has a 250mh to reduce power.

    Which method is better?
    Does it even matter at this point?
  2. To simpify the question:

    More or less MH for flowering?
  3. I always supplement my HPS with some blue spectrum light. The plants will absorb the blue light, and the more complete spectrum will definitely help them flourish.
    I wouldn't turn off the HPS. Just supplement them with your MH. Generally anywhere up to 1/3 of your lighting can be blue(5000-6500k).
    You can run a whole cycle under MH if you like, so obviously the plants continue to absorb the light, but you will see a smaller yield. The reason that HPS orange/red spectrum(2200-2700k) is used is that it induces faster/more flowering. The reason for this is actually the pattern of the sun in the wild. During the longer days(veg), most of the light that plants get from the sun is when the sun is high in the sky, when it emits more of a natural blue spectrum(direct sunlight is rated at 5000-6500k, though this isn't really a perfect measurement, just as close as we can get). Once the days shorten, a higher percentage of the light comes from sunrise/sunset, which is a redder spectrum.
    All of this being said, redder light should be your primary light source during flower, but if you add blue to it you will see more/earlier/ faster trichome development leading to a better final product. Don't expect an increase in yields, though, just better smoke.
  4. thanks for the comment.

    so...  bigger or smaller light?
  5. its down to the size of the room/canopy
    and the yeild smoke your looking for

    need a lot more info to answer the question
    but bcgreenbeard gave you a lot of good advice
  6. Personally, I would run all 3 lights for all 12 hours so long as the space allows it. The 400w MH won't give off much heat, if that is an issue with the 1000w. I would certainly not turn off the HPS for any length of time. Think of light as food. It is their main source of energy. If you underfeed your plants you lose yield and potency.
    If you have a power consumption issue, I can't really give you any advice there.....that is something that you will have to decide for yourself, as it can be a balancing act to keep costs and consumption down....
    Basically, it's either run 2 lights, or run 3 lights on for slightly less hours.
    The 3 lights on, all right next to each other for less time is a similar theory to having a light on rails, that only hits the top part of the plants with full intensity for 6 hours a day as it is crossing back and forth.
  8. growing room is larger, but the footpring of plants is 3'x8'

    The question boils down to: 'more or less MH?'
    1st option of 400w puts it at less than 1/3MH.
    2nd option puts it at 1/3 MH to HPS ratio.
    In the end I doubt it would make much difference side by side in either yield or quality as the would get about the same watts and be on for 12 hours both ways, but was hoping somebody here had experience on more intense MH lights for shorter times vs less intense for longer.

    Forgot to comment on this:
    'Think of light as food.'

    It is the plants food, but just like eating too much McDonalds will make a man fat or too many nutes will burn your plant there has to be a balance. The 2 lights on all the time has worked fine, but wanted to get some blue in there without having to go 50/50 MH/HPS as that seems like a waste of juice when you consider the MH's smaller lumen and yield output.

  9. as the canopy is 3ftx8ft, you need the two 600w hps on 12 hours and something to box the grow in, to reflect all the light you can back down on the plants.
    I know you want to reduce the power but this will reduce the yeild a lot, this is big money to lots of growers out there
    so if there was a way to cut back on power and pull the same yeild it woulkd have been done
    It's a constantly evolving process, and it's been done, yes.
    Current ways to reduce power:
    - HPS - Don't use old style incadecent bulbs during flower or you'll use 10x the amount
    - reflective material - effectively gives more light without more power
    - movers - I'm not a big fan, but they can increase yeild by 25% while only using a couple watts of power.
    - scrog, stadiums and other ways to surround lights.
    Other ways to increase yield without increasing power
    - nutrients
    - hydro and/or using larger soil pots
    - increase sq. footage and/or increase airflow
  11. fine turning your room will help to increase your yeild and there diffent ways of training your plants but it alway going to be the same.
    1.2x 1.2m room doing a sea of under a 600w (12/12),basic nutes and full canopy, good airflow and setup will give you the best yeild in the quickest time and using less electria, nutes

    Plants only nees to be 12" tall in this set up is good

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