CAUTION: CMH (Ceramic Metal Halide) light dangers.

NLNo5

NLNo5

Active Member
Keep in mind UV in low levels may be useful for your plant but UV in high levels can really jack up your plant. It's a miss conception that plants can handle any kind of UV, they are actually sensitive to it just like humans.

If you've got enough UV in your grow op to burn your eyes or skin during short exposure periods that means you've probably got enough UV in there to fuck up you plants during 12-24 hrs a day exposure. Chances are likely that there is not really that much UV in the light source.

I do like the idea of wearing sleeves, gloves and shades. I also like the idea of running auto's so that I can mess with the plants during the dark cycle and not trick them out too much. Then I don't have to have the CMH on while I'm fondling my plants.
 
karr

karr

Well-Known Member
As i said earlier too, too much will indeed be bad for plants. I have not done the research to find proper levels and intensities. What i do know is that the unfiltered CMH bulbs have UV output and i also know that this bulb grows some great plants.

I know my eyes are at particular risk. Growing up on the water as well on ski slopes, i learned early that my eyes are hyper sensitive.
 
karr

karr

Well-Known Member
Sunlight>everything... for now anyway :p

I have been thinking about that recently. I mean if a plant can absorb up to five times normal co2 as occurs in nature, i am also sure the amount of nutrients are not available in hardly any natural places so more there too, how about light? obviously some places on earth get more/higher intensity of light than others, how many times past average available light will a plant utilize? Spectrums/heat/etc would play a large role, but someday maybe it will be possible to grow bigger plants indoors than out.
 
C

cktricky

Member
i will agree that these CMH lamps emit a good amount of UV radiation. i have the phillips 400w and the packaging for the bulb warns very loudly the UV dangers of the bulb.

The outer bulb is designed to block, or i should say, hold back SOME of the UV radiation. i believe there is still a shit ton emitting through the outer glass. ive worked under the light for a few min daily and i swear a feel like the back of my neck has been effected. granted im burning in an open fixture. im going to start wearing sunglasses because i think the dangers of these bulbs are underestimated. just my 2 cents. important post here.
 
Bonzi Lighthouse

Bonzi Lighthouse

Well-Known Member
Ronjohn7779 said:
I doubt these bulbs produce much if any UV radiation. UV is in the far blue spectrum. I just have a hard time believing these bulbs can get in that range. I'm not calling you liar at all (I hope I don't seem like I am), I'm guessing you're being a bit paranoid is all. I could see you having a sensitivity to that spectrum of light in terms of creating eye fatigue. Being under or looking at any intense light for very long (even 5 mins is considered long) is enough to make anyones eyes feel out of whack.

If these bulbs produced much if any UV radiation then there should be a warning on the box. Not only would they put you at risk for skin cancer, but they would do the same for your plants too. Yes shockingly plants can get skin cancer too, I know this sounds stupid but its totally true. Thats a worry for Australia's plant harvest since they still have a whole in their Ozone layer.
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You tell me. This is the Philips spec sheet. UVB is one of the advantages of the CMH bulbs.

http://www.growlightexpress.com/pdf/cmh.pdf

RECOMMENDED WARNINGS, CAUTIONS,AND OPERATING INSTRUCTIONS
WARNING​
​
​
​
​
: “These lamps can cause serious skin burn and eye inflammation from short wave
ultraviolet radiation if outer envelope of the lamp is broken or punctured. Do not use where people
will remain for more than a few minutes unless adequate shielding or other safety precautions
are used. Certain lamps that will automatically extinguish when the outer envelope is broken or
punctured are commercially available.”This lamp complies with FDA radiation performance standard​

21 CFR subchapter J. (USA:21CFR 1040.30 Canada: SOR/ DORS/80-381).
 
virulient

virulient

Active Member
karr said:
Many of you that have been considering switching to CMH lights should take to heart the warning about the UV radiation that these bulbs emit. I have just installed this light in my 400w hps(magnetic of coarse) ballast.

Well, today i spent about 10 minutes under the normal HPS bulb, as usual. Today i forgot my sunglasses which i try to use but often forget. No adverse effects before. Later i installed the new CMH bulb and proceeded to water my plants. Total time under light was less than about 5 minutes again. Well after the 5 minutes my eyes were feeling stressed, similar to a day at the beach without glasses. After feeling this i went and got my sunglasses and continued my work.

Now, around 4 hours later, my eyes still have a slight sting as i feel i soaked up a little burn in this very little time.


So just a little cautionary story, if you are considering a CMH Bulb just make sure you use sunglasses(even more so than hps and mh) and a long sleeve shirt/gloves isnt a bad idea. These bulbs are hot start rated, so i imagine turning off your light before entering the room shouldn't be too much of an issue. I would treat this light as you would with the harsh UV lights out there.

Be careful.
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When I was 17 I was working at a body shop and my first day welding I welded all day without my helmet on. I'm originally from Florida and it was like 105 and 100% humidity. Anyways, my eyes just felt really tired and shit, I went home. All night that night, from like 6pm to 3 am it felt like I had sand in my eyes and they were non stop watering. When I rubbed them it made it MUCH worse, yet the whole time I had this horrible urge to rub them. Kinda like how you HAVE to itch a rash or pick a scab. Anyways. the moral of the story is......good tip. Flash burn is a terrible terrible experience. I wouldn't wish that on many people in this world.


PS - In case anyone is wondering, no, I had no long term symptoms. This happened 7 years ago and I still have 18/20 vision.
 
L

lostNug

Well-Known Member
I am a welder by trade so I weld all day everyday. I have gotten flash burn many times. Like someone poured sand in to ur eye balls. Its the best when it starts happening while ur driving on the freeway. That's the best

I've been runnin a CMH for a lil more then a month and have not noticed any skin burns or eye irritation. But I will say its not as easy on the eyes if ur not wearriing sunglasses compared to HPS.
 
karr

karr

Well-Known Member
Keep in mind your fixture and the bulb itself play into if/how much uv gets out.

Also keep in mind its not one or two exposures that is going to hurt you, but 6 mo this of every other day or whatever just might cause some serious harm. The moral of the story is better safe than fucked.
 
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