MH vs HPS lights

Just recently got my lights and the MH bulb was broken! My plants are about 3 weeks into growth and all I have left to use is the HPS light bulb. Will this affect anything? I know the HPS lights are typically used for flowering and MH for veg.

its fine. Mh for veg and hps for flower is a marketing scheme. You want full spectrum through veg and flower. Just like the sun.

Hey andrew, you can still use the hps for veg but its not as good because of the color spectrum, although Ive read plenty growers who got very good results using only hps or even mh. Nowadays you can get dual spectrum bulbs which are used for the whole grow. Btw if the bulb was broken on delivery then you should contact the seller, they should send out a replacement. Good luck

hyroot said:

its fine. Mh for veg and hps for flower is a marketing scheme. You want full spectrum through veg and flower. Just like the sun.

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So it'll be fine if I left them with the HPS light for the rest of the grow? Or should I swap out for a new MH that the company will send?

andrew rivera said:

So it'll be fine if I left them with the HPS light for the rest of the grow? Or should I swap out for a new MH that the company will send?

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its fine with the hps. You will get less stretching too . Closer node spacing

andrew rivera said:

So it'll be fine if I left them with the HPS light for the rest of the grow? Or should I swap out for a new MH that the company will send?

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The hps will be fine as hyroot states, but if you can get another mh from the seller then I would do that...you already paid for it so why not use it...plus it will extend the longevity of the hps. good luck

hyroot said:

its fine with the hps. You will get less stretching too . Closer node spacing

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Okay cool. And quick question, I have a setting on the lights for the amount of lumens it sends out, should I just keep it on 100%?

andrew rivera said:

Okay cool. And quick question, I have a setting on the lights for the amount of lumens it sends out, should I just keep it on 100%?

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yes. Lowering the output can shorten the life of the bulb.

ive swiched my flower room from all hps to both, since i added the mh in flower, my plants stretch less and buds are much fuller..im also thinking of just switching over to conversion bulbs,,so i can use the same bulbs vg-flower...has any of you used all conversion bulbs insted of hps or mh?? was there a change in bud weight or any changes going from hps or mh to a conversion bulb??

hyroot said:

its fine with the hps. You will get less stretching too . Closer node spacing

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I thought ur suposed to leave mh in for the first 2 weeks of flower to prevent streching?

oilfield bud said:

I thought ur suposed to leave mh in for the first 2 weeks of flower to prevent streching?

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Nope that's supposedly to transition from veg to flower. But really a marketing scheme to make you buy more than one light for the same area.

When you change lights you will have a spectral transition no matter what. You should be running the same full spectrum in veg and flower.

you get tighter node spacing with a metal halide in veg

HPS is fine the whole grow though.

- Jiji

just switched over after 20+ years of hps/mh to ceramic disharge lamps,,so far so good. you may want to check out my journal..

I am very satisfied with the work my 600 watt MH has been doing in veg. If I had to choose one bulb for the entire grow though I would use an HPS conversion bulb.

hyroot said:

its fine with the hps. You will get less stretching too . Closer node spacing

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I think you have that backwards. MH gives you closer node spacing and less overall stretching.

If I was going to use only one it would be the MH bulb. I know that doesn't really help the OP. You can use HPS in a pinch but I would get the replacement MH bulb for sure.

DirtyMcCurdy said:

I think you have that backwards. MH gives you closer node spacing and less overall stretching.

If I was going to use only one it would be the MH bulb. I know that doesn't really help the OP. You can use HPS in a pinch but I would get the replacement MH bulb for sure.

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Nope, in veg the blue region induces stretching and the red region suppresses stretching. Then in flower the red region induces stretching and the blue region supresses stretching. 730nm Infrared will induce stretching in both veg and flower. And quite a lot too.

Im pretty sure you got it backwards to buddy, I just looked it up in my marijuana growing bible, haha I know im a newb, but I still use it as a point of reference

Ether one will work. Hps will give you the most light though.

hyroot said:

yes. Lowering the output can shorten the life of the bulb.

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The same for increasing if it has that feature too......Yes, some do.

oilfield bud said:

Im pretty sure you got it backwards to buddy, I just looked it up in my marijuana growing bible, haha I know im a newb, but I still use it as a point of reference

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I go by experience and university studies.

Most of those books like the canna bible are out dated and wrong.

I've spent years experimenting with various spectrums. So I'm actually right. The cannabilble doesn't know shit about phytochrome state and measuring par. Back then they still measured plant lighting by lumens and not par (umole/s)

Try it and see for yourself.