# HPS for vegetative growth



## Alistair (Jun 23, 2008)

I know a person that uses HPS for vegetative growth as well as for flowering; he told me that the plants grow faster under HPS than with MH.  I've noticed that in the past when switching from my 400watt MH to 400 watt HPS when going from vegetative growth to flowering the plants actually do more vegetative growth in the first two weeks of flowering than when vegging for five weeks.  That is to say, in just 2 weeks the plants more than doubled in height.

With that in mind I wonder why I haven't used the HPS for the whole grow, beginning to end.  I've noticed that the lumens are about 49,000 mean lumens for the HPS, but only 22,000 mean lumens for the MH.

Is it recommended to use an HPS for vegging?  If they grow bigger faster, it seems like a good choice.  What are the pros and cons of using an HPS for the whole grow?

Thanks,

Alistair


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## IllusionalFate (Jun 23, 2008)

That increase in height you noticed is because HPS lamps promote much more vertical growth instead of lush new leafsets and tight nodes. Most growers who veg with an HPS will have a taller plant with more space between nodes, and most likely a decreased overall yield.

It sounds like you are getting vertical growth mixed up with vegetative growth. The blue spectrum from an MH lamp creates the best vegetative growth possible, the shorter overall height will help with the light penetration and get strong light to the leaves all over the plant instead of just the top half.


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## LowRider (Jun 23, 2008)

just buy a 2 way HPS unit.  This way you have MH for veg and HPS for flower.


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## gcarlin_818 (Jun 23, 2008)

I am using HPS all the way through my plants started from clones and I am about 1 moth into veg they are about 1ft 2in..When i set them into the tray they were about 5 in so I would say for the most part HPS is better....Getting my camera replacement battery so in 2 days I will post pics of the girls so you can see for yourself...Peace and Green Fields


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## brushybill (Jun 23, 2008)

as im sure you know, when you switch to 12/12 your plants can double or triple in hieght, this has more to do with plant biology than what type of light  you are using, the plant knows it has limited time to get its work done. and gets to it
    the general consensus here is mh for veg and hps for flower, blue and red, i personally use t5s for veg, but more for energys sake ,  i would probably get better results with mh, but im cheap. just my2cents


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## Alistair (Jun 23, 2008)

Ok, thanks.  That's good information.  I forgot that plants tend to double or triple in height for the first couple of weeks or so into flowering.

Also, regarding height, I'm planning on keeping them short anyway; I just started LST on my seedlings a few days ago.

Thanks,

Alistair


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## brushybill (Jun 23, 2008)

my t5,s have kept my plants nice and short, i can put the lights 2" from my plants without any heat issues and i have nice tight node spacing.
 i have heard a lot of folks here who swear by mh, although i have no experience with them, so i can't say

 good luck


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## Alistair (Jun 23, 2008)

Yeah, a long time ago I grew using eight  40 watt fluorescent bulbs.  I used only four of them for vegetative growth.  Then, for flowering I added the other four, placing them on the floor under the plants facing up at them.  I believe six out of the eight were cool white, and the other two were warm and pinkish in color.     Well, that was the best grow ever!  The buds were dense, and there were lots of them.  The plants were healthier too.  I have more trouble with HIDS.


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## The Hemp Goddess (Jun 24, 2008)

brushybill said:
			
		

> my t5,s have kept my plants nice and short, i can put the lights 2" from my plants without any heat issues and i have nice tight node spacing.
> i have heard a lot of folks here who swear by mh, although i have no experience with them, so i can't say
> 
> good luck



I totally agree on the T5s--I wish I had discovered them sooner.  I used to use a MH, but no use T5s exclusively for cloning, moms, and vegging.  When put into flowering, the HPS induces stretching.  I believe that it would do the same thing if used for vegging.


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## Puffin Afatty (Jun 24, 2008)

*I use 1 lamp for everything, a 400w HPS.  I get excellent yields and potency*


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## thief (Jun 24, 2008)

the plants i grew start to finish under hps were in soil but the fan leaves got huge as big as my hand even. in the growbox i have mh the fans stay smaller like palm sized is it the light or the dirt/hydro difference i dont know. maybe i`ll do a test this fall when i start the basement garden again.


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## Aurora_Indicas_Dad (Jun 24, 2008)

mh is "the best bulb to veg under" if your going by what the experts say.everybody has their own luck with using different lights.i've seen plants that looked just fine vegged under a hps..then on the other hand ive seen some plants that stretched under a hps..i think if your gonna veg under a hps,you definitly want an air cooled hood,this way you can get the light closer and you wont have as bad of a stretch.


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## CasualGrower (Jun 24, 2008)

I veg under a couple 4 ft floro shop lights, like 12 bucks from wally world, I use a Daylight (6500K) and a Kit/Bath (3100Kelvin) bulb in each light.... Veg growth is tight and get a nice lil bushy girl.


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## gcarlin_818 (Jun 24, 2008)

heres what my plants look like under HPS at 3 weeks

http://www.marijuanapassion.com/forum/showthread.php?t=27519


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## Dubbaman (Jun 24, 2008)

:aok: mang way to grow i use the HPS for all the growing, too lazy to switch bulbs and such  just about to take a few out after this 12/12 seed grow if your wondering what anyting looks like the link is in the sig  no veg period but the whole grow was under the HPS less like a week or so at the start till i got a couple of others harvested


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## Alistair (Jun 24, 2008)

Yeah, as Aorora Indicas Dad said, to each his own.  Gcarlin's babies look nice and healthy; however, how will they look after all is said and done?  I imagine they will remain healthy, all things being equal, but how will the spacing between the internodes be?  

My friend is happy with his setup using strictly HPS, but what would his stuff look like if he used MH for vegging?

Dubbaman grows 12/12 from the beginning.  If I were doing the same, I'd for sure use the HPS too.

For right now, I'll stick with the MH for vegging. 

Regarding the fluoros, they sure do a great job for vegging and they don't cause heat stress.

Well, thanks again,

Alistair


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