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HPS vs MH for Flowering


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#1
WinterGreenGrow

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I have done a few grows under my current 400w MH, and I'm wondering if a HPS light would be a worthwhile investment. I realize an HPS light is a better option due to the light spectrum, but has anyone actually done grows with both? I'm wondering how much of a difference it really makes in yield.

Anyone with some first-hand experience flowing with both? What are your thoughts?

#2
matumbo

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I know this doesnt answer Ur question but have you considered throwing on an LED for flowering? One that doesn't have blue in it's ratio. Would increase your yield more that by just choosing mh or hps.

#3
toastybiz

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You definitely want HPS rather than MH for flowering.

#4
stinkiefingers

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Get a 400w HPS for flowering and use your 400w MH for veg, and ur set

#5
WinterGreenGrow

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I realize HPS is the ideal setup for flowering, what I was asking was the difference in yield between the HPS and MH.

What will the HPS improve? Bud density? Size?

Say a 400w HPS is $150, is it going to make enough difference to pay for itself in 1 grow cycle?

If anyone can go into more detail than "yes buy an HPS, its better" that would be appreciated.

#6
bentripin

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do you not have a switchable ballast?

I just got a new 400w lumitek HPS bulb for $68 at local store and swaped out the old MH in a few moments.. for a price like that why not if you can?

#7
WinterGreenGrow

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do you not have a switchable ballast?

I just got a new 400w lumitek HPS bulb for $68 at local store and swaped out the old MH in a few moments.. for a price like that why not if you can?


No my ballast isn't switchable. If it was then I would already have a HPS bulb installed. ha. I even have a HPS bulb that I could use.

I was thinking since I already have a hood and a HPS bulb laying around I could just buy a HPS ballast. This brings my price down to around $100 for the upgrade, but I would still like to hear some opinions on HPS vs MH. When it comes to growing there are so many things that people swear by that don't really make that much difference, so I'm trying to figure out how much of an improvement I could expect from HPS.

#8
bentripin

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Its a fact that HPS puts out more lumens for the same wattage vs anything else artificial, including MH. This should translate into higher output if you know what your doing.. If its cost effective, thats up to you to decide. If your looking for higher yields then this is the best place to start.

for example: 400W MH @ 8" is ~25k lumens, 400W HPS @ 8" is ~35k lumens..

from http://forum.grassci...ould-light.html

#9
toastybiz

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MH is not a good choice for flowering, so you should see much better bud development with HPS. Fatter, denser, everything.

#10
tplat

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No my ballast isn't switchable. If it was then I would already have a HPS bulb installed. ha. I even have a HPS bulb that I could use.

I was thinking since I already have a hood and a HPS bulb laying around I could just buy a HPS ballast. This brings my price down to around $100 for the upgrade, but I would still like to hear some opinions on HPS vs MH. When it comes to growing there are so many things that people swear by that don't really make that much difference, so I'm trying to figure out how much of an improvement I could expect from HPS.


MH puts out a blue light spectrum that mimics more of the natural sunlight during the earlier and middle parts of the year when plants are focusing more on veg growth and towards the later part of the year the sun starts to emit more red light spectrum (HPS) that tells the plants its time to start bearing fruit and or seeds because its nearing the end of its cycle. Thats what I have read and been told by a few people at a nursery.

#11
Doughnut

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If your running a older coil type ballast why not run Ceramic Metal Halide?

#12
zshaw369

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I have flowered under just hps, under just mh and also a mix of the two side by side. The best results i have found in flower for my organic grow would be like this, I run mh for veg then i switch to hps for flower up until week 6-7 then i switch to mh to finish them out. the metal halide will produce better tasting more resin and tighter buds but it will not have as much yield, thats why i use a combo of the two the hps to pack on the weight then the mh to finish it out for flavor and aroma and density. hope this helps

#13
Swami

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MH puts out a blue light spectrum that mimics more of the natural sunlight during the earlier and middle parts of the year when plants are focusing more on veg growth and towards the later part of the year the sun starts to emit more red light spectrum (HPS) that tells the plants its time to start bearing fruit and or seeds because its nearing the end of its cycle. Thats what I have read and been told by a few people at a nursery.


You have been told wrong. This myth keeps going around with no scientific backing.

#14
hickstylez

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Ok so dude said that 400w mh is 25k lumens and hps is 35k lumens.

so I was at the store looking at fluorecsent lights and noticed that all the 6500k t-5s same brand G&E had 2650 lumens when the 2700k same brand and style g&e said only 1750 lumens.

now is this for just fluoro? or at the store they make the 2700k less lumens on purpose for a different style of lighting?

so if thats true then...
HiD lights have diff lumens?

if the HPS has more lumens... the only reason people WOULD EVEN USE MH FOR VEG (aside from keeping the plant all natural with the light cycles and all) IS less lumens so they can mature a plant shorter heights?

So when they flip they can keep them under height control?

I mean am I wrong here It seems a few of these arguments/posters maybe be wrong.

help!?

#15
pun650

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Ok so dude said that 400w mh is 25k lumens and hps is 35k lumens.

so I was at the store looking at fluorecsent lights and noticed that all the 6500k t-5s same brand G&E had 2650 lumens when the 2700k same brand and style g&e said only 1750 lumens.

now is this for just fluoro? or at the store they make the 2700k less lumens on purpose for a different style of lighting?

so if thats true then...
HiD lights have diff lumens?

if the HPS has more lumens... the only reason people WOULD EVEN USE MH FOR VEG (aside from keeping the plant all natural with the light cycles and all) IS less lumens so they can mature a plant shorter heights?

So when they flip they can keep them under height control?

I mean am I wrong here It seems a few of these arguments/posters maybe be wrong.

help!?


400w mh is 39k, 400w HPS is 55k

It's about spectrums, even though the mh is less lumens it's more effective for veg. The plants like the blue spectrum better. For flowering they bathe in the red and love it.

I believe it's just the kelvin rating that changes the lumens.

#16
hickstylez

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400w mh is 39k, 400w HPS is 55k

It's about spectrums, even though the mh is less lumens it's more effective for veg. The plants like the blue spectrum better. For flowering they bathe in the red and love it.

I believe it's just the kelvin rating that changes the lumens.



yup same old same old answers. dude. I know early in the year spring the sunlight hits harder and is bluer and I know in the fall the sun wanes and becomes more reddish in color.

this is making no sense ur basically saying like i should water my plants with gatorade because THATS WHAT PLANTS CRAVE...... u see what im saying?

I understand there are a gazzillion different light spectrums and almost every single lightbulb has a slight variancee.

What I'm trying to say is if your going to tell me that blue is good for veg and red is good for flower dont. ive heard it.

now then anyone scientist's out there? not just people who probably know less then me?

Edited by hickstylez, 13 July 2012 - 08:21 PM.


#17
pun650

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Anyways... Just because the HPS has more lumens doesn't mean it's more efficient for veg.

It's about the spectrum.

Thanks for the turdy come back btw.

Throw all the lumens you want at it, the better spectrum will do better.

Btw, I only have 1 light. A 400w HPS. Babies are veggin under it ATM, an I can't complain.

Edit: read your first post in this thread.

The kelvin rating CHANGES the lumen output.

Edited by pun650, 13 July 2012 - 08:36 PM.


#18
hickstylez

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lol u dont realy understand what this thread is about dude its about MH FOR FLOWERING NOT HPS FOR VEG..... but.... thanks for the cookie cutter knowledge bro. (im sure if you cant understand the totality of this thread u have not been able to read more then me about cultivating.

#19
Carl Poot

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Can you "veg" autos under an HPS? Meaning grow it from seed to harvest under a hps..no mh?

#20
tplat

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Can you "veg" autos under an HPS? Meaning grow it from seed to harvest under a hps..no mh?


Yes, some growers use HPS for the whole cycle. If you want to mimic mother nature more accurately you would use a mixed spectrum for both cycles. Like a 3:1 blue to red spectrum ratio for veg and a 3:1 red to blue spectrum for flowering.




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