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400w MH and 400w HPS at the same time

  • by mikelamb22
  • Nov 08 2008 03:27 PM
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Posted 08 November 2008 - 03:27 PM

my question is. I'm gonna use both of my 400 watt lights to flower with (400w metal halide and 400w high pressure sodium), Will the 400 watt metal halide be to bright to put in with the 400watt high pressure sodium.
My concern is that the metal halide will cancel out all the light from the high pressure sodium. That damn metal halide is a bright bastard.
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  • Kocf_owned
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Posted 08 November 2008 - 04:32 PM

Its all about light spectrum

Mh bulbs run at about 4,200 k all the way up to 6,400k (also known as Full spectrum)

High pressure sodium run at 2,300 k to 2,700k

Now for metal halide lights the higher spectrum the better
and for HPS the lower the better

MH bulbs mimic the long blue/white light of summer and spring 12-16 hours of sun light
and are essential for vegetative growth

HPS mimic the shorter red/yellow days of fall 8-12 hours of sunlight a day
and helps stimulate bud production..as well as cutting the amount of light u give them to 12/12....now u can use one all the way a MH or a HPS and its even better when u use them together to grow...but for flowing i would just use the HPS...


MH light promotes growth and leaves

HPS light on a 12/12 cycle with promote BUD production..meaning your plant will almost stop growing and start putting in all its time into growing you some Sticky fat dank Nugz..so in my opinion keep that MH outa ur flowering room lol...

Edited by Kocf_owned, 08 November 2008 - 04:48 PM.


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  • curbendurben
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Posted 08 November 2008 - 04:34 PM

Ideally you should use MH in Veg And use HPS in Flowering, but also the rule of thumb is more light = more bud the fact of the matter is that HPS gives out round about 30% more light that MH so it wont cancel out your HPS just rotate your plants by a 1/4 to 1/2 a turn each day and you will be surpised at the results

i know this because its what i use but not at the same wattage your using

i have 3 lights altogether
1 x 250w MH in My Veg room

and in the flowering room i have
1 x 250w HPS and the last one is a
1 x 250 watt MH/HPS switchable
i only switch the last one over to HPS when I have about 3weeks of flowering left,

go for it coz thats what its all about trial an error
but you will be surpised at the results

Hopes this helps :wave:

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  • max11max
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Posted 08 November 2008 - 04:37 PM

my question is. I'm gonna use both of my 400 watt lights to flower with (400w metal halide and 400w high pressure sodium), Will the 400 watt metal halide be to bright to put in with the 400watt high pressure sodium.
My concern is that the metal halide will cancel out all the light from the high pressure sodium. That damn metal halide is a bright bastard.


If you can use both then do it. Lots of info on the net about using both at the same time. Much better than one.

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Posted 08 November 2008 - 04:38 PM

hey curbendurben..gota Question for ya...i have a 250 MH/HPS system and im growing 3 plants..do u think i should upgrade to a 400 watt system?

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Posted 08 November 2008 - 04:59 PM

Hi kocf_owned i love the name :D

Depends on how much space/money you have, coz if your going increase the wattage you will also increase the heat genarated and in turn you will need to upgrade your ventalation system aswel,
But for 3 plants i would say its false economy
i have 4 plants growing with my setup in rotation 4 in veg room and 4 in flowering room
and i get excellent results
but if i where to grow 6 or more then i would upgrade every thing, lights, room size, fans, etc..
but i have a rule: if it anit broke then dont try to fix it

hope this helps:wave:

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Posted 08 November 2008 - 05:13 PM

If you can use both then do it. Lots of info on the net about using both at the same time. Much better than one.



amen^^^

dual or full spectrum will increase crystal production due to the uv rays the metal halide produces & the hps will keep the buds tight, best way to go mate you,ll not look back & will do it every grow.

peace......................:smoking:
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