Mixed spectrum (HPS & MH) for flower.

I currently have a 1000w HPS, and have been considering adding a 600w MH to that on a light mover. Would 600w MH to 1000w HPS be a good mix? Looking to take advantage of the UVB in the MH as well. Anyone doing, or have done this with good results?

Why? just buy a hps mh combo lamp or dual spectrum lamp. if u have ur heart set on another fixture dont go mh, get a cmh instead.....way better results then mh.

Good point on the cmh and metal halide will work too.

The extra blue light helps with plant health and compactness and the uv can increase potency.

I would want only 400w of mh with 1000 hps for best buds with a good calyx to leaf ratio. Too much blue light made leafy buds for me.

I like 2 600 hps to one 315 cmh per 4x8 area after testing many variations.

Also it has been proven that if the hps is switched for a 10k finishing mh or good cmh the last two weeks or so the thc bump can still happen.

It is not necessary to have it the whole time but like I said and the university of Michigan and Utah have published. Some blue light helps keep leaves greener.

MichiganMedGrower said:

Also it has been proven that if the hps is switched for a 10k finishing mh or good cmh the last two weeks or so the thc bump can still happen.

It is not necessary to have it the whole time but like I said and the university of Michigan and Utah have published. Some blue light helps keep leaves greener.

Click to expand...

I ordered a UVB light to hang over the plants for the last two weeks of flowering, do you think I should keep hps for that time or switch back to mh? I run 2 400w bulbs in my set up.
This is the UVB light I ordered:
(34" T-5 HO Fixture *High Output* with ARCADIA D3+ 12% HO Bulb * )

Farmer.J said:

I ordered a UVB light to hang over the plants for the last two weeks of flowering, do you think I should keep hps for that time or switch back to mh? I run 2 400w bulbs in my set up.
This is the UVB light I ordered:
(34" T-5 HO Fixture *High Output* with ARCADIA D3+ 12% HO Bulb * )

Click to expand...

I don't know about that bulb but like I said above some added full spectrum light will help plant health. And the uv can increase potency the way you are planning. But I would be careful introducing a high uv source at the end. The mh has lower uv than that 12% bulb I'm sure.

I might use that uv bulb from the start of flowering on a timer to get the plants used to it.

Sorry I can't help more.

MichiganMedGrower said:

Also it has been proven that if the hps is switched for a 10k finishing mh or good cmh the last two weeks or so the thc bump can still happen.

It is not necessary to have it the whole time but like I said and the university of Michigan and Utah have published. Some blue light helps keep leaves greener.

Click to expand...

So just switch out the bulb? I've got at least 2 weeks left on 2 plants and probably another 3 or 4 on another.

Raven121415 said:

So just switch out the bulb? I've got at least 2 weeks left on 2 plants and probably another 3 or 4 on another.

Click to expand...

Yes. For years growers have been switching to metal halide the last two weeks for a thc boost.

And the few percent possible increase in thc still happens.

Solis tech made a 10k finishing bulb with more uv for his purpose.

MichiganMedGrower said:

Good point on the cmh and metal halide will work too.

The extra blue light helps with plant health and compactness and the uv can increase potency.

I would want only 400w of mh with 1000 hps for best buds with a good calyx to leaf ratio. Too much blue light made leafy buds for me.

I like 2 600 hps to one 315 cmh per 4x8 area after testing many variations.

Click to expand...

The 1000w hps mh combo lamps are 60% hps and 40%mh.....according to their data that combo percentage will produce the best results for people seeking "blue" light.

bottletoke said:

The 1000w hps mh combo lamps are 60% hps and 40%mh.....according to their data that combo percentage will produce the best results for people seeking "blue" light.

Click to expand...

Are these double fixture lamps your talking about? I am not finding anything besides DE fixtures.

Raven121415 said:

Are these double fixture lamps your talking about? I am not finding anything besides DE fixtures.

Click to expand...

Its 1 lamp (a lamp is a light bulb, a light is a fixture) that has a mh fitament and a hps element, its 2 lamps made into one.

I used to finish under a UV bulb but found a mix of hps/mh in flower returned the same results without a dedicated finishing area/fuss.

I like to run several 60-100 actual watt blue CFLs during my grow, bare bulb either hanging or on a pole. I move them around as I see fit. what I noticed is the buds with the added CFL always are denser and more colorful (wont tie die your plant but adds different shades of green and can help purple strains shine more)

that being said I will be adding two 4 lamp T5 HO fixtures with full spectrum/blue/far red. and two UV lamps for my next run. future will probably be led and/or CMH with UV.

I have switched to MH last two weeks on several runs and it did seem to help frost the buds.
I think 400-600 watt MH added to your HPS will help

bottletoke said:

The 1000w hps mh combo lamps are 60% hps and 40%mh.....according to their data that combo percentage will produce the best results for people seeking "blue" light.

Click to expand...

Didn't know we were talking about the lamps with both bulbs built in.

And the university of Michigan explains different types of plants need different amounts of blue/red light for best production results.

Leafy greens would require more percentage of Blue to make the best leaves. Cannabis requires more red when flowering to help yield and flowering response.

So there is no one perfect horticulture bulb just because Hortilux made a product.

And the 400 and 600 need to be at different heights to be effective. I think that is why the double bulbs are not very popular.

Do some research. Most growers that mix bulbs go 2 to one with single ended. Or 1 1000 de to 1 315.

Going with more mh or cmh hurt my yield 30%. And the quality was not better.


Also one of those sides of the dual bulb may burn out prematurely. Expensive replacement for half a bulb.

This is what I have found from extensive research and testing.

MichiganMedGrower said:

Didn't know we were talking about the lamps with both bulbs built in.

And the university of Michigan explains different types of plants need different amounts of blue/red light for best production results.

Leafy greens would require more percentage of Blue to make the best leaves. Cannabis requires more red when flowering to help yield and flowering response.

So there is no one perfect horticulture bulb just because Hortilux made a product.

And the 400 and 600 need to be at different heights to be effective. I think that is why the double bulbs are not very popular.

Do some research. Most growers that mix bulbs go 2 to one with single ended. Or 1 1000 de to 1 315.

Going with more mh or cmh hurt my yield 30%. And the quality was not better.


Also one of those sides of the dual bulb may burn out prematurely. Expensive replacement for half a bulb.

This is what I have found from extensive research and testing.

Click to expand...

the hortilux (most likely all the 2 in 1's) have been designed for cannabis and the various distances and wattages are calculated into that design or at least thats what their sales rep stated at a growers conference 2 years ago, btw apparently if part of the lamp dies a full replacement is given if its within a year of purchase.

i tried everything and now i just use the 1000w de's alone for flower, i have 4 plasmas and 6 induction lights collecting dust. transferred all cmh's to my veg room because i found them to not make that much of a difference if any at all. i could see the lec/cmh's making improvements on smaller plants but for the size i grow i would need 2 per plant, thinking about trying the cmh de in the future is not

bottletoke said:

the hortilux (most likely all the 2 in 1's) have been designed for cannabis and the various distances and wattages are calculated into that design or at least thats what their sales rep stated at a growers conference 2 years ago, btw apparently if part of the lamp dies a full replacement is given if its within a year of purchase.

i tried everything and now i just use the 1000w de's alone for flower, i have 4 plasmas and 6 induction lights collecting dust. transferred all cmh's to my veg room because i found them to not make that much of a difference if any at all. i could see the lec/cmh's making improvements on smaller plants but for the size i grow i would need 2 per plant, thinking about trying the cmh de in the future is not

Click to expand...

I was a sales manager for 20 yrs. Reps are trained to say things like that. They didn't design anything new. They just combined existing parts.

And I wish I could use de's. But I have low ceilings.

Sounds like you have determined the same as me about the rediculously overhyped cmh bulbs.

Nobody talks about or admits this but it seems to me and ed Rosenthal proved it years ago but lower wattage grows less potent flowers. He advised not to go below a 600hps for flowering. Said 1000 is better. And he was referring to the quality when he said that.

MichiganMedGrower said:

Nobody talks about or admits this but it seems to me and ed Rosenthal proved it years ago but lower wattage grows less potent flowers. He advised not to go below a 600hps for flowering. Said 1000 is better. And he was referring to the quality when he said that.

Click to expand...

the truth hurts, just proved it to a buddy last crop. he grew an amazing plant under 600 de's, i said"imagine what it would be like under 1000's. he took a cut and put it in my warehouse.....he is now the owner of 48 1000w gavitas. he was in denial for 2 years until he could actually see the proof.
i cant really say much cuz i always fall for newest flavor too but i always end up going back to vanilla. Lol

Well, being that I am still fairly new to all this, and I already own a 2 mo old 1000w HPS, I will just opt for the 400w MH and a light mover. I am going out Friday to purchase a 1000w 10k MH bulb for the finish. I see Ultra Sun and Solis Tek both have them reasonably priced. Any advice on which one to go with.

I assembled my components over a long period of time, so I've got some old school 400w MH ballasts and a couple of 600w digitals, + various cheap LED panels. I've run lizard lights with HPS and gotten great results.
Mixed spectrum provides the best results for me, but it's more like "mixed gear" and the spectrum a side effect.
I recently put some seedlings and a couple of donated plants under a bare bulb 400w MH and they did *not* like it! Probably the UV. I switched back to HPS and they are doing much better.
BTW what happens to spectrum if you drive them below max voltage? A buddy gave me a reflector that had a 1,000w EYE hortilux HPS bulb in it. I'm sure the output is diminished because he ran it for at least a year. All I've got is a 600w digital ballast to drive it. I'm running at the highest setting -- "600w boost".