# HPS vs MH for veg



## warfish (Dec 7, 2009)

I have a 250w hps lamp that puts out 33,000 lumens.  I could purchase a MH conversion bulb for this fixture for vegetation growth but the lumens on it are only 22,000.  It is just a small closet grow, 2x2 so I will be well over 5,000 lps either way.  I am moving some bag seed plants so the good seeds I bought have the big room. 

So the question is do I spend the money on the conversion MH bulb or stay with the HPS?

Thank you,
Warfish


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## 4u2sm0ke (Dec 7, 2009)

This  may  help

http://www.marijuanapassion.com/forum/showthread.php?t=1974

Take  care and  be safe


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## warfish (Dec 7, 2009)

Wow, that is a great thread!  Thank you very much 4u  

Warfish


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## Growdude (Dec 7, 2009)

I have great results vegging with HPS, Ive done a side by side and there was no visible difference in the plants growth.


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## meds4me (Dec 7, 2009)

I "Believe" U of Wash. did a study and found only a 10% difference between the two (hps vs MH) being the hps was better but lacked the better blue spectrum as the MH does... ~


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## 7greeneyes (Dec 7, 2009)

plants under metal halide have grown at a slower rate then under hps, thats the only discernble diff I;ve found.  Blues are kinder for regenning and if u got femmed seeds and lay to the enviro factors that decrease shock and hermans.

i.e. More blues, more N, 18/6 hrs and ...cooler temps I believe was the influencing factors...

p.s. Metal Halide has more blues = more UV's which are harmful to the human physiology. i.e. cancer possibilities.


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## Alistair (Dec 7, 2009)

Thanks 4u.  I read the thread that you posted above.  It mentions a seedlings stage and a vegetative stage.  I've always considered it vegetative growth as soon as the sprout pops the surface.  Am I right, or does vegetative growth start sometime after the seedling has grown a few leaf sets?


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## BBFan (Dec 7, 2009)

The side by side test I just did- just harvested, no final weights yet- using a 400 watt MH side by side with a 400 watt HPS- resulted in slightly more dense bud under the mh and slightly more (and larger) fluffy bud under the hps.

I'm liking the denser buds right now!


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## LEFTHAND (Dec 7, 2009)

ostpicsworthless:


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