Growing with mh AND hps

Discussion in 'Growing Marijuana Indoors' started by BigBoyMattyG, May 23, 2010.

  1. Hello everyone!! I love this site and decided to join. You guys have great info. Don't make fun of me because I only had 3 seeds and only one of the germinated. I've got my one little "girl" (i hope) and had a question regarding growing with mh AND hps. I have a small closet that's 3'x3'x4' with a 150 watt HPS Sunsystem. I found a 70 watt MH exterior light like the ones you find at Home Depot and rigged it up next to my 150 HPS in the room.

    Does this benefit my little plant to run both at the same time? Has anyone had a setup kinda like that? Right now I'm 5 weeks into vegging and was thinking about using both lights throughout the entire grow. What do you guys think?
  2. mh is veg and hps is flower. runnin them both helps potency. you need more wattage though. take the watts your runnin....divide it by your areas sq footage. not 50 or better? bigger light...hps all the way if you cant afford the mh. or throw some flouros in for the veg spectrum.
  3. Um, I'm a little confused... If what your saying is true, then even a 400 watt mh wouldn't be enough. (only 25 watts/sq ft.) 50 watts a sq ft?? That sounds a little high because in a small space like mine a 400 watt gets way too hot and to get 50 watts a sq ft I'd need a 1000 watt which would definately get too hot, even with proper ventilation. Can someone comment on this?

    Actually I mis-measured my space. It's 2'x2'x4' or 16 sq ft. I only have one plant and both of the lights are hung 12" above the plant. I've got 2 fans running below the plant and a little 6" clip fan blowing on the lights and the temps are a little high, about 76-80 degrees depending on the day. I figured the extra 70 watt mh would help speed up the vegging but if it's not gonna help then I'm going to take it out to keep the heat down.
  4. Assuming 2x2x4 means 2 feet wide each way and 4 feet high, then you only have 4 square feet. Height means nothing with calculating square footage.

    With that, 200w would put you at exactly 50 w/sq ft.
  5. LOL, thank you for the correction, that makes alot more sense. I think I was thinking of cubic feet or something... Length X Width X Height right?? Anyways, that would put me at 55 watts per sq ft.

    What I'm still wondering is what kind of results some of you have had running both MH and HPS throughout vegging and budding?
  6. like i during flower ups potency. and if lights are to hot....just get an enclosed light so you can duct heat
  7. Thanks Ninja, but I've already spent 200 + dollars on my setup and so I have to work with what I've got. I guess I'm looking for a more technical answer. I understand that using both will aid in the potency of my finished product, but I'm look for more specific information. Like growth rate, if sexing shows early using both vs one or the other, etc. I'd really like some info from someone who's actually tried this method themselves.
  8. Dude, guy already has both MH and HPS lights and can run simultaneously. That's an expensive bulb there.

    BigBoyMattyG I'm currently flowering under an MH light and a bunch of CFLs. The plants both showed sex in 3 days and packing on the trichromes really fast. Buds have not swelled up that much but they are still early in flowering. I bet the lights you have will give you awesome results during flowering. My suggestion is, use the MH with some 6500k CFLs for veg, for maximum branching, and then switch off the CFLs and introduce the HPS once plants in 12/12 for more trichromes (MH) and fuller buds (HPS). That way you win in both cycles.
  9. its no advantage running them together. your different lights and light cycles are designed to mimic the sun through a season. the differences in the 2 lights is color temperature. metal hydride is designed to mimic spiring when the light is whiter and hotter and hps is a yellower cooler fall light. its the change in light that starts budding. you can run them both..but i dont think it will help.
  10. In general, MH is best for veg, and HPS is best for flowering. However, this has mostly to do with the type of light it is simulating, IE Summer light versus onset of fall. When the days are shorter, there are longer (proportionally) periods of "red" light, with sunup and sundown. This is what the HPS bulb simulates for an indoor grow.

    However, I've been reading a lot of convincing articles that state a plant can use both types of light during all phases of growth. This is why many people are switching to using both a MH and HPS bulb (or those dual spectrum bulbs that have both in one bulb) for their entire grow, only changing the light cycle, not the light quality, between veg and flower. Many others are augmenting their HPS with CFLs during flower, to give them some blue spectrum as well.

    Short answer, for one plant your lighting setup sounds great to me. If you have the ventilation to run them both, I think you're going to do fine. Hope it's a girl! Good luck!
  11. Spectrum is not what starts budding, hours of light is. FullmoonCat is very right. Sunlight does not change from blue to read according to the season. It's just that more red is available due less hours of daylight between sunrise and sunset.
  12. Okay, THAT'S THE INFO I WAS LOOKING FOR. It seems like alot of people say that for best results you should use MH for vegging and HPS for budding because of the type of light they produce. I agree with FullmoonCat because if the plant responds only to a specific type of light then we wouldn't have so many options out there to choose from (i.e. CFLs, MH, HPS and so on) I know that since plants respond better to the MH spectrum for growth and HPS spectrum for flowering, it would seem that combining the 2 would provide the best of both worlds. I know this seems awfully tedious for just one plant, but if I can get this to work right I'll be increasing my plant count in the future and open the space up for more room.

    When I read posts from some of the veteren growers, they all seem to be particular to one or the other and it's been difficult to find info on past results when using both lights to grow. That's why I'm kind of excited because if this proves worthy, I might end up starting a new technic in growing.

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