MH vs HPS Bulbs

Discussion in 'Growing Marijuana Indoors' started by radman60, Nov 10, 2010.

  1. #1 radman60, Nov 10, 2010
    Last edited by a moderator: Nov 10, 2010
    I'm going through the learning curve in an effort to start my first grown I have found that more and more people are using 1000w systems and not bothering with anything less.

    From talking to individuals as I accumulated my lighting equipment, I'm running across more and more people that have said they don't use MH bulbs during the veg period.

    It appears that a lot of them stick with the 1000w HPS bulb right from the start.
    Reasons being:

    1. Healthier and stocky stalks
    2. Shorter veg period (usually 2 to 3 weeks) during the 18/6 cycle.
    3. Quicker height gain prior to 12/12 flowering period
    4. 4 to 6 weeks for the flowering period
    5. Overall growing period (from clone receipt to chop) reduced from 9 to 10 week cycles, down to 8 week cycles
    6. Bigger yields.
    I have accumulated both 1000w MH and 1000w HPS lights/ballasts for my first soil grow and I'm wondering if there are more individuals on this forum that have used only HPS lighting equipment for their soil grows and what their final dry yield results where vs using 1000w MH bulbs for the veg period.
  2. Dude listen, you have to start off slow.
    The reason everyone is using a 1000 watt lighting system is because they are growers that know what they are doing. After your first grow, things will get easier.

    Yes you can use hps during veg, no big problem, but the light spectrum is diff. so it might cause the yield to be less im not sure.

    You wont get 4 to 6 weeks flowering, usually takes at least 8 weeks sometimes 12.

    What are you going to use to cool your room, Im using 7 cfl light bulbs and i have to have an a/c during the winter to make sure my closet is cool.
    Cfl's are a good way to start, i prefer them all the time.
  3. Hi Ed (good name by the way.. I've always said 2 Eds are better than one :p )

    Cooling will not be an issue.. Room is in a barn and I got snow on the ground already :) I'm going to intake from outside the room through a louvered vent so I can control the amount of -0 air coming in.. :)

    Equipment is already bought and is not returnable cuz it's all used.. I'm still working on the room and I'm just trying to collect more info from the experienced on which way to start off before I take delivery of the clones in a couple of weeks...
  4. Make sure there are no bugs, and the humidity is good, because if your going to be starting off with clones you need a high humidity.
  5. #5 radman60, Nov 10, 2010
    Last edited by a moderator: Nov 10, 2010
    1st room is going to be an 8x12 and I have "No Pest" strips in the grocery bag already :)

    During the veg stage of the first grow i plan on building a box (8x8x7.5) so I can start vegging a 2nd grow before the first one finishes flowering..

    Would like to get 2 or 3 grows in before spring as it's will be to hot in the barn after that.. Not sure if I will get into a summer outside grow.. To many other things on the go and to many people around...

    oops.. Forgot.. For humidity I plan on setting out a few pails full of water throughout the room.. If that is not enough, I'll get a humidifier..

    I've also got a 1000gph submersible pump in a 45 gal container that will be used to set up my watering system (on a timer)..

    I'm a little nervous about posting any photos right now but once I get the room setup I may start a journal and post a few photos.. :)
  6. So you have no fans or blowers or anything for that light.
    Seriously man your gonna be surprised at how hot your barn gets. Its not easy, you would def. need in the summer a blower and a/c unit and stuff like that.
    But good luck anyway.
    Dont be nervous about posting pics, your not doing anything illegal if you dont have any plants growing yet. And you cant really get caught on here man, dont worry about it.

    Check out my grow
  7. Kind of veered of topic here but I've got 2 scrubbers circulating air in the room and one big one exhausting air through a larger scrubber out of the room plus I have 2 oscillating fans to move air around in it also..

    Not to worried about heat/humidity/watering management.. I think I have that under control.. I'm looking for opinions on using 1000w HPS for the entire grow (vegging and flowering) vs using 1000w MH lights for veg and 1000w HPS lights for flowering.

  8. I've always used 600w MH bulbs for veg and 1000w HPS for flower, I grow indoors and see 5-6oz yields per plant on a 16 week cycle. I veg for about 5-6 weeks and then flower for 10, depending on which strain I'm growing.

    I like 600w lights for veg because combined with a good duct system, it lets me place the light about 3 inches from the tops of the plants without burning them. This keeps the plants from stretching too much and getting too tall - I prefer to keep them short and bushy because I can crowd more of them around a light. 7' tall trees look impressive but it's not a very efficient way to grow indoors.

    High temps in your veg room can be ok. High temps in flower room are definitely not. I have 4 1000w HPS lights in a 12x12 room and it can get pretty warm in there. I grow in basement rooms specifically designed for this purpose and even with 4 inline fans, cement walls, floor, and central air running in the summertime, I still saw my temps getting up around 85 degrees. If you're growing in a barn in the summertime, you are going to need a portable air conditioner unit.

    Best of luck man, keep us posted!
  9. U use mh for veg and hps for flower. It's simple. If u have to use the hps use it their won't be much difference and it won't hurt ur plants
  10. And I have to add that 4-6 weeks for flowering is unrealistically fast. Sure, at that stage there will be buds flowering at all of the nodes, but if you look at the trichomes under a scope they will definitely not be ready. They need more time to fill out and bulk up or you'll be harvesting shitty fluffy buds with a low THC content. Not good.

    8-10 weeks flower, minimum. Be patient and let them mature, buy a scope and wait for the trichomes to get milky white and lean over. Then they're ready.

    Lots of people do things just because their friends do it that way, or because they heard a rumor that Method X is a surefire way to grow sick phat buds in 3 weeks. But realistically, it doesn't work that way. Vegetating cannabis needs light in the white spectrum, if you use HPS bulbs you are depriving it of that. All of the professional growers use MH for veg and HPS for flowering because that's what works. If some other combination worked better, I guarantee that the professional growers will immediately adopt that method. But for now this is what works best.

    Learn from the experts, not from your friends. :)
  11. imo seems a little bit of missinformation here.

    1. some maybee, others maybee not.
    2. dont think thiers any differnce in veg time, for sure not 2-3 weeks worth
    3. some maybee, others maybee not.
    4. still need the 8 weeks minimum(for most) unless its a sog setup and at that point MH wouldnt matter any ways.
    5. nah, thats to fast for most people unless its what you are geared towards, like a sog setup or something. 2-4 weeks veg, and 8 weeks of flower pretty much no matter what bulbs u use.
    6. sure, but dont think this has much to do with MH vrs HPS in veg.

    i have done it both ways and so far have really not found any reason to use mh during veg. over momas sure, why not. but for actually rooms its to much hassle. i guess a perfectionist with some free time on thier hands might go that route but if you have the time/energy to do that i would hope the rest of the room is dialed as can be. i really dont think the yield factor would be great enough to justify the added expense of replaceing a second bulb, further would be very hard to get actually data since no 2 runs ever seems to be that identical.


  12. That's why I started this thread.. Awesome corroborative info ...Thankyou Thankyou.. :)
  13. Thanks blindbud.. Much appreciated..
  14. Thanks again Ed
  15. It has been a while since I have posted here but I figured I would chime in with my 2cents on the subject to continue the discussion along. My very first grow alone is partially documented on here, I went with a very low budget grow, but used a 400w 4500K MH bulb for veg and a 360 HPS/MH 2100k conversion lamp for flower. Surprisingly I returned and rather nice yield on just a few plants. I have not tried using an HPS bulb only for both veg/flower, but people I know that have seem to do just fine with their yields. I really think it boils down to what you are comfortable with, and what your ideal yield goal ultimately should be. I can say this though, I personally prefer using a MH bulb for veg and an HPS for flower, because each bulb is designed specifically for their respective stage. MH emits in the proper blue/white spectrum for optimum vegitative growth, and HPS emits in yellow/red spectrum for optimum bud production.

    Each bulb (your better brands, EYE, Sunmaster, SolarMax, etc.) does emit small amounts of its counter spectrum, MH bulbs do emit smaller amounts of the red/yellow spectrum, and vice versa for the better brand HPS bulbs. Technically speaking you could flower with a MH bulb, just don't expect good yields. Flip that over, you can veg with HPS, just don't expect 7' trees. Then again though, we don't want 7' trees, that is not how oyu grow efficiently. Compact and condensed is what you want.
  16. get some T-5's, soil and some solo cups. Start there. Learn, educate, grow and repeat.....
  17. I have some inside info from a seasoned grower and i can only pass on what i was told directly.

    Seedlings and clones - CFL's

    HPS all the way !
    Best HPS for lumens and cost is the 600W
    1 x 600W over each plant (40cm from canopy)
    People boasting 2 pounds + per light, this system will give you around 5 Pounds.

    1. Rain Water - giving you plenty of room to get to you 1400
    2. Good genetics - get seeds from seed banks, not bagseed.
    3. Weekly flush.

    Like i said, this is only what i've been told by a Gunja Guru....
  18. well your "guru" has lied to you. Why would you need a 600watt light per plant?? 5 pounds?? Per plant/light?? NO. Unrealistic to say the least. Its honestly bullshit. Rain Water?? WTF? Why CFLs for veg??? Sure they work but he has a Metal Halide 1000w already... That would be downgrading to go to cfls from a 1000w MH. Weekly flush??? I didnt think he was running a hydro system and even then it is not necassary and its a waste of nutes. Pretty much the only thing that you said that I agree with is to use good genetics. In the end a good goal is 1 gram per watt.... If you get that then your are doing something right. And yes MH veg and HPS for flower unless you can run and cool both during both stages. I have seen some great results from people running dual spectrum setups. My new setup will be dual 400 watter inline with each other in cool tubes cooled with a 165 cfm can fan and I will be using 2 MH bulbs for veg and 2 HPS for flower.
  19. Correctomundo.. I'm going to try some light stress training (LST), little bit o pruning and I'm aiming for 15" to 18" during veg stage before I kick it over to flower.
  20. I've got 10 setups all of them 1000w..

    5 MH and 5 HPS.

    I have 40 feminized clones coming and I was only going to use 3 of them with 36" parabollic hoods.. I could use 4 but I was told when using parabollic hoods 3 would be more than enough for the 40 ladies.

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