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Flowering- Metal Halide vs HPS

Discussion in 'Indoor Growing' started by growstrong, Jun 21, 2008.


    growstrong Active Member

    I have three strains going; first one and flowering nicely about a month ahead of the White Berry and Carmelicious which are in the flowering stage also.

    I have been using a Sunmaster Neutral Deluxe Metal Halide 400W (36,000 Lumens) which is suppose to great for veg growth and flowering.
    I also have a 400W HPS Agromax (55,000 Lumens).

    I am still confused as to which bulb is best now. The plants I started more flowering more recently I thought would benefit more from the 'neutral deluxe'

    I am thinking of switching for a few days to see what happens. The bag seed plants are flowering beautifully....

    Any input would be much appreciated.


    kushfarmer Active Member

    Metal halide is best for vegitation, HPS is best for flowering. This is because the MH's strength is in the warmer colors of the spectrum, your red-orange area, the HPS's strength is in the cooler colors, your blue-purple area. The flowers respond better to the cooler area of the spectrum. Couple this with a high phosphorous intake during this period and skipping your last watering or two, your yeild will be denser and more potent. Essentially, THC helps the plant retain moisture. So, when it's faced with a low water supply the plant, in a sense, panics and starts to produce more THC to better utilize what moisture it has and comes accross. Lowering the humidity during this time will help aswell.

    Pidgeon Well-Known Member

    You got close kush, but the MH is more of a blue spectrum which is great for vegetation while the HPS is more of a red spectrum which is what plants crave for the flowering stage.

    WormSlayer Well-Known Member

    Use both :D

    kushfarmer Active Member

    Thank you...Pidgeon's right. I got my wires crossed. Good lookin' out Pidgeon.

    growstrong Active Member

    I got my wires crossed when I first got the bulbs. Used the MH first...dumdedum.
    I switched after a few weeks but just noticed two hermaph.'s, maybe one male but they were flowers with white hairs...I dunno...I switched bulbs and am using the MH now.
    I had thought it was better to use the HPS when I brought the younger plants in and had read many of the HPS were fine for the whole shabang.
    I think I will wait a bit longer on the veg grow next time. I used flourescents 2 20w to get them started, 24/7...maybe shorten the light on time too as I hear they show sex sooner if you do say 18/6.

    growstrong Active Member

    Trying to save on electricity...everything is so friggin expensive. That's why I decided to grow my own...I am sick of shelling out money for crappy weed and anything really good is a fortune. Plus who knows where it came from and what they used for chemicals and shit!
    Ya think a lot more people are doing this?
    I like it for medicinal and other reasons....I hope in my lifetime I see it legalized!

    kushfarmer Active Member

    My wife and I started growing for the same reasons. As to it's legality...

    Gen. 29-31
    Then God said, "Look! I have given you every seed-bearing plant throughout the earth and all the fruit trees for your food. And I have given every green plant as food for all the wild animals, the birds in the sky, and the small animals that scurry along the ground—everything that has life.” And that is what happened.
    31 Then God looked over all he had made, and he saw that it was very good!
    And evening passed and morning came, marking the sixth day.

    I can't argue with God

    ceestyle Well-Known Member

    you had it right. MH first, HPS second.

    growstrong Active Member

    I read this thread and a few others on here regarding MH and HPS.

    From all I have read here, in a book and doing other reading it's MH then HPS. whew
    It sounds like if you are going to use one HPS would be better???
    Now I have to switch the bulbs again the plants will 'stress' and not behave for a few weeks! :?

    However everyones experience is different. There are so many other factors, CO2 for example...I added that a couple of weeks ago...there is a high and lo button...ummm which one?
    This is my first grow and I picked up a book, looked around here and a few other sites and dug in.

    Lots to learn but it's gardening and I love it :wink:

    mikeNASTY13 Active Member

    i'm vegging with an hps and cfl's. they are working just fine together

    growstrong Active Member

    My husband has never smoked...he is cool about my stuff, it's not hurting anyone. Live and Let Live.....kindness y'know.
    I see people boozing, killing folks with cars, fighting, and so on....
    ganja folks not so much...
    Now that I grow it has even more meaning.


    kief13 Well-Known Member

    it takes time and knowledge to get da hang of it at first,and the co2 question of hi or low depends on the size of your closet i belive

    kushfarmer Active Member

    Sorry for the confusion...I think pidgeon and I messed you all up.

    There is no problem using two. MH first for veg, then HPS for flowering. I'm sure they'll be ok.

    kushfarmer Active Member

    Either HID will work just fine all the way through and produce respectable yields. The point is, if you have both, order is everything.

    Pidgeon Well-Known Member

    Yeah, sorry about that. I should have been a bit clearer on my response as to which bulb produces which. Regardless, either bulb you use will get the job done but with just a margin of difference between them. But to clarify a bit: MH (blue spectrum) is best for vegetation and HPS (red spectrum) is best for flowering/bloom.

    growstrong Active Member

    Hey all you nice helpers...no one messed me up, you all were great and together we figured it out!....when I switched bulbs yesterday it was right...HPS....
    the MH will rest for a while till I need to get the little ones going before flowering. I think the acronyms and other lingo used when beginning growing get many of us confused..
    I thank you all for helping me get the MH vs HPS right. The bulb I am using now has a nice amount of blue but more of the red and orange...
    One thing I mentioned was getting a few hermaphrodites...I moved them outside, can't kill em after so much care! :-) They were 'feminized' seeds, next time won't pay more for those I can see for myself and save

    Off topic....my picture you see is of our 13 yr old German Shepherd, we lost her on Thursday to a degenerative disease...pain meds helped for a few months...in the photo, that is her smile, no kidding she was my K9 kid and her K9 brothers are like lost boys without her.
    If you have an animal please treat them kindly...and if you know someone who abuses them...do what you can even if it means calling animal control...

    "The greatness of a nation and its moral progress can be judged by the way its animals are treated."
    - Mahatma Gandhi

    growstrong Active Member

    Thanks on the CO2, it makes sense.
    Has anyone tried the CO2 bucket system? CO2 Boost Bucket System

    I am still using it during flowering...can't hurt it I don't think?

    Pidgeon Well-Known Member

    That stuff is a rip-off. You would be saving yourself a lot of money if you just get a 1 gal container (milk jug or something of that nature) and clean it out. Then get some active yeast (bakers yeast or brewers yeast) and some sugar. Mix maybe 6 cups of sugar and 3 tbsp of yeast and toss it in the jug, then fill the jug to 1/2 to 2/3 full with water and mix well. Then poke a hole in the top of the jug so the CO2 can be released into the air. This will last for 2-3 weeks depending on the environment. It is much cheaper than the product you are buying and is essentially the same method minus a CO2 bell on the top. I use this in my grow room and it works fine for me. Anyway, I hope this helps and saves you some of that valuable paper. Plus, it will make your grow room have a hint of beer (a plus or minus depending on if you like beer or not).
    Last edited: Jun 22, 2008

    jon2 Well-Known Member

    Too lazy to read whole thing, but if anything hasn't mentioned, your buds will come out better if you go MH, HPS, then MH again to finish it off.

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