mh/hps question

Discussion in 'Lighting' started by Bipolar_Crazy_Patrick, Mar 21, 2012.

  1. Im working on my first grow, and im still in the educational phase. I understand that MH bulbs are best for the veg. phase, and HPS are best for flowering. There will be 4 plants under a 600w hps for flowering, but im not sure about the MH for vegging. Should the wattage be the same as the HPS. Also, Are there fixtures that can take both hps and mh bulbs, and I can just swap them when the time comes? If not, I may have to use flourscent for veg, cuz I really cant afford to buy a whole seperate fixture.
  2. There are switchable ballasts that will run either bulb but a ballast designed for one won't properly run the other without modification.

    Ballast aside, the fixture for an HPS is the same for a MH as long as they both use the same type of socket.

    Vegging typically requires less light and therefore a lower wattage because the plants are much smaller than they will end up in flowering. You can, however, use the same wattage- the vegging plants will simply have a surplus of light available.

    A good enhanced spectrum grow bulb can perform as well in veg as well as it will flower. The GE Lucalox PSL/XO is the best example of this.
  3. So the enhanced spectrum blub is good for the whole grow? Vegging uses less light? I thought you wanted almost 24 hr. light for vegging. I was going to go with 18/6.

  4. Vegging uses a longer photoperiod; more hours of light per day; but doesn't require as bright a light source as the same plants in flowering. For example, I veg four plants in 3L bottles with the tops cut off until they are around 9" tall, repot into 5gal buckets and then flower until they are at least 2' tall. During veg, these four small plants take up barely more than 1x1' of floor area. During flowering where they triple in size, these same four plants end up needing more than 2x2' and need a much brighter light that covers the larger area.

    Yes, a good enhanced spectrum lamp can work wonders through the entire grow in the same way that the sun grows plants through their entire lives.
  5. Ahhh i see. Thanks.
  6. How about adding a couple regular flourescent from my garage with it as well? Would that be good because of the extra blue, or would it be too much?
  7. #7 Cuzin Red, Mar 23, 2012
    Last edited by a moderator: Mar 23, 2012
    There's no real need to use a MH at all. I've grown for the last few years from seedling or rooted clone to finished crop all with HPS alone. With the exception of low level flour. lights to root clones with. The plants grow vegatively just fine under HPS and I haven't experienced any significant stretching over when I owned a 1000w MH.
    BTW: Right before HPS lights became available in the early '80's I grew entire crops under a 1000w MH that bloomed out better than what some would suggest for flower development. In fact the results gained with HPS is relatively minimal over MH. And it's the intense lumen output of HIDs (MH or HPS) that produces big, tasty and potent buds more than the lesser difference of a slightly bigger yield with HPS.

    Edit: Some growers insist the best results come from using a 50/50 combo of MH and HPS or the more complete spectrum and pricey Son-Agro bulbs during blooming.
  8. Thanks guys, I appreciate it. The less stuff I have to buy, the better.

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