Difference between Hps and MH during flowering?

Discussion in 'Growing Marijuana Indoors' started by kkjones714, Sep 23, 2013.

  1. I have a 400 w eye hortilux Mh bulb and a 400w solar max hps bulb.just recently purchased them both together with a new ballast to upgrade during my flowering period. I am curious to know if any one knows the difference it would make if I use the mh bulb during flowering just curious of how it would grow. I have it under the 400w hps right now just wondering if it would be different then using mh during flowering.....also what if I'm able to use both would that be beneficial to the plant

    I know there's a bunch of links about lighting but I just want to know if anyone has already done it thanks

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  2. It would work but it's better to use the HPS.  I have also heard that using MH in conjunction with HPS causes more bud, but also a more airy product.
     
  3. #3 bananamber, Sep 23, 2013
    Last edited by a moderator: Sep 23, 2013
    The spectrum that high-pressure sodium bulbs put out triggers the release of certain hormones that increase flower production, while metal halide is better for vegetative growth.
     
    You would see more bud production using HPS during flower. If you can, you could even use both throughout the plant's entire life because MH also causes more compact growth. So mixing spectrums would result in more bud growth but also denser buds. That's why I've always grown mixed-spectrum, even though I've only ever done indoor grows with fluorescents.
     
    By the way, the mixing spectrums thing is a hotly debated topic with growers, some say it's better and some say you should only use HPS-like spectrum during flowering.
     
  4. what do you mean more airy?

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  5. would using both during flowering increase my yield...after one of using my new bulb I saw huge changes...so I'm guessing using 800w of lighting would increase yield I'm guessing ?

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  6. Yes, using both and thereby doubling the wattage will definitely increase your yields.
     
  7. MH alone will do fine but both will boost yield for sure. MH will grow tight buds with lots of frost just not as fat of buds as HPS.
     
    I think MH is better quality and the HPS is better yield. But that's just my person preference. I would never discourage anyone from flowering with MH.
     
  8. what about switching bulbs during veg? I'm in the process of getting another hood and ballast for my extra 400w MH bulb so right now I've been vegging at night in my tent with my flowering plants under my hps and during the time my flowering are sleep I take them out of the tent and put them in a closet with fans and then use my mh for the last 12 hrs of vegging

    so 12hrs of hps then 12hrs of mh during the day is that bad

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  9. #9 tplat, Sep 23, 2013
    Last edited by a moderator: Sep 23, 2013
    Vegging under HPS tends to make the plants stretch more then compared to vegging under MH. Outdoors during the veg part of the year they get more blue light spectrum that's why they don't stretch as much but in the late mid to later part of the grow season they get more red then blue light spectrum and that's when they start to stretch. There are dual spectrum bulbs that you can buy and the few I just looked up for a 1000 watt set up have a 600 watt HPS arc  and 400 watt MH arc thingy in them. How well they work I have no idea haven't really seen any grow reports or journals on them.
     
  10. thanks for the input...does using both bulbs at the same time differ from getting a dual spectrum bulb?

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  11. I think with the dual spectrum bulbs you lose a little bit of lumens put out by each. I`ve seen a few dual bulb light hoods and there are a few dual ballasts on the market that can run two HID bulbs at the same time at the same watts. I`ve noticed on the dual spectrum bulbs they go with more HPS then MH and in flowering I can see how that would be beneficial but in veg outdoors you get more blue light spectrum then red. So if it was me running two lights I would go more MH in veg then HPS and vice versa in flowering to see how it does.
     
  12. the closer you are to the spectrum of the sun, the better off you will be, it has always been that way and it will always be that way since every plant known to man has been evolving with our sun for millions of years.
     

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