Hello all

I have a 400W MH setup currently. I purchased a SunSystem 2 light/ballast and it came with a generic MH bulb. Im thining good for vegging. Very bright/white light.

My plants have been on 12/12 for about 2 weeks now. It just dawned on me today that they might do better with a bulb more suited for flowering.

Is this true? Should i switch out the bulb? Or is using the same bulb common and ok?

What are some good options?

Thanks

I would be switching to HPS,

thanks for your input zig but ive heard that before and am unsure about it. the science behind different spectrums make sense to me.

the MH v HPS debate seems to be a matter of preference(from what ive read in threads here and other sites). is there a spectral difference between ur standard MH and standard HPS?

is that difference greater than say getting a red spectrum MH bulb? or should i not even bother with this since its my first grow, just see what happens and then care more when my bought seeds are to the flowering stage?

If your ballast is setup to switch between a MH/HPS.. I would switch for sure. I think your HPS will have the light temperature closer to what the plant needs for proper flowering. You are looking for something in the 2700 - 3000 Kelvin for flower.

You are basically trying to replicate how the natural light changes thru the course of the growing season. In the spring/early summer.. you are getting the "whiter light" (6500 Kelvin or so?) from the sun. In later summer/early fall you get more of the red spectrums from the sun.. in the 2700K range, when your plants are in flower.

That is the way I understand it.

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GreenGoblin

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good info greengoblin.

might have to buy a conversion blub but tryin to make sure thats even THAT beneficial.

thanks for the input.

You could get a conversion HPS bulb for the MH ballast
but don't bother. If you are growing for youself, stick with
the MH right through.

yeah just growing for me and my roommate.....i read one place that HPS makes the buds bigger but that with MH they are more dense and higher in trics. any validity to these assessments?

As with all things, yes and no :>

I can only speak from personal experience, generally this
is what I found...

HPS = more volume, pretty looking buds, more heat, more stretch.
MH = less volume, gnarly looking buds, bushier plant, more frost/resin.

The actual yield weight difference was minor.

If you don't care about bag appeal, MH all the way.

But what the hell do I know, I do drugs!

You'll be OK. Just make sure you have ENOUGH light for the area you are trying to cover. (50 watts per sq ft).

Fyi...in generalizations where actual values aren't known....

Hortilux lamps are 2150 Kelvin
standard hps lamps are closer to 3K
Agrosun MH's are 3500'ish
standard halides are 4K
Sunmaster "Daylight" MH is 5600K
Hortilux "Blue" 6500K

ww

HPS will out yield the MH with a better calyx to leaf ratio. How much will it out yield it by? Hard to say exactly but I'd guess the HPS produces at least 25% more bud, with a ceiling of probably double what the MH can accomplish.

Don't forget "blue" photons take more watts of energy to create than "red" photons. But the plant doesn't see light "energy" or lumens, it sees photons. And a "red" photon is more effeciently processed into bud than is a more blue one. More energy to make less effecient to use in the end. That's why HPS wins, but a noticeable margin, everytime I've seen a heads up.

Finish this grow under MH, then use some of it to buy a conversion bulb. If you get an extra 5 or so grams it paid for itself.

Youll get way more than that. I'd guess eventually you will switch to straight HPS for flower. That MH would be perfect for veg, and could easily feed a 1K HPS.

If by yield you are talking about weight, then 25% more is bull.
If you mean volume then I grant that.
The weight diff is minor at best.
The only thing that matters to most is the final products ability
to treat a given condition...or to get you snibbled..MH wins.

1 bulb use MH
2 bulbs use one of each
3 bulbs use 2 MH and 1 HPS, reverse for flowering.

think im just going to grow through with the MH and see what happens. after all this is the first grow and its about learning as much as it is about gettin tasty herbs.

almost finished a grow box to start seedlings/clones in so ill focus on that while my big girls flower away. :-D

thanks again everyone.

used to use HPS all the time to flower 430 hordilux
last fall i was going too buy a 1000 watt HPS.
the guy at the hydro store talked me into getting a 1000 MHand a sun master bulb witch is whiteand blue but also has lots of red, as well.
i use it for both veg and flower..
i would like too get a 600 HPS for flower. and maybe if they where not so much money i would like to try the LED.but i dont see that happing with the prices

Can you get 450 grams off a single 400 MH, not moving, in a horizontal reflector? That's often done with 400w HPS, I personally would be happy getting 340 grams off a 400w MH (about 25% less than a pound), and that would be higher than any grow I've seen using a 400w MH. Last time I did it (as a test to end an argument) I barely pulled 225 grams. The bulb wasnt fresh but even so HPS was well more than 25% higher.

A gram a watt? LOL! try harder. 1.6 to 1.8/w
I can do that with a MH or a HPS.
We've done enough side by sides over the decades with
enough strains that I am quite comfortable saying I don't
care how good you think your kung-fu is you get MAYBE
2-3 grams more weight under the HPS380.
HPS product will look like 800g, MH will look like 300g
But the product under the MH will be better.

Like I said, if you grow to sell or take pictures of it = HPS
Growing for your own head = MH

This is STRICTLY with a single 400.
A larger bulb or multi bulbs will change the ratio drastically.

But hey, what ever works for you. Its all good.

you are saying you get 700 grams from a static, horizontal 400w Metal Halide? This I've got to see. You got a link?

I could get that with a mover or vertical setup, using HPS, but a stationary MH? I've been growing for almost a decade and a half and never heard of anyone taking down close to 2 pounds from a 400 MH.

dont be too bothered about mh v hps if its your first grow and the girls are looking good.i used mh right through my first grow with tasty results.

same thoughts here.

either or can be used through all stages.
hps has more red of a spectrum and mh more blue. Either can be used and get pretty decent results but of course blue is better for vegging and red for gaining the most possible bulk in flower. Its said that Mh has uv rays as well which are supposedly the accounting for a more potent plant in the flowering run with the but I wont repeat it as fact because very little that we know about growing pot has actually been studied in a lab and most is done with home testing in an unscientific manner. So I dont even know for myself that its the uv rays stimulating more resin and wont repeat that claim.

oh yeah actually forgot to add this....
growing with both light types combined will get a grower the best possible results. Not only do you get the best of both worlds but the light will also come from multiple sources (thus being more intense) then and the plants less likely to be shaded anywhere like it could be from one bulb alone