Cmh bulb life?

Nutty sKunK

Nutty sKunK

Well-Known Member
So I’m just starting a new batch of seedlings under my 630w CMH. I’ve noticed the growth seems to be way slower than when I first used the light. Even slower than the previous grow.

Bulbs are about 3 years old and have been used at 20/4 for about 5-6grows.

Anyone know how long these bulbs last and if there are noticeable differences in growth when the bulbs start to fade?

cheers!
 
Nutty sKunK

Nutty sKunK

Well-Known Member
Rocket Soul said:
This is what the lux meter is for... Keeping track of "is it the light?" or possibly other stuff. Raising pots or lowering light could be a way forward
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Light is fixed. I guess I could get a lux meter to take the guesswork out of it. Raising pots k could do but this may be an indication the spectrum is off?

I was reading somewhere that the blue spectrum is the first to go in cmh Argo bulbs which would result in slower veg

I’ve ordered a couple replacements and will pop a new bean under them and see if it grows faster
 
ttystikk

ttystikk

Well-Known Member
Nutty sKunK said:
Light is fixed. I guess I could get a lux meter to take the guesswork out of it. Raising pots k could do but this may be an indication the spectrum is off?

I was reading somewhere that the blue spectrum is the first to go in cmh Argo bulbs which would result in slower veg

I’ve ordered a couple replacements and will pop a new bean under them and see if it grows faster
Click to expand...
Plants veg well under red or blue light, provided there's enough light and all other parameters are on point.

Therefore, check all of your other parameters; fresh nutes? Good EC and pH? Water temp (if applicable)? Air temps and humidity? Fall is here and a cooler growing space will slow metabolism. So will excess moisture or excess dryness. How about CO2? Closing up your apartment may mean it's depleted unless you're home breathing on them.

If all that is good, then it's your lights.

Personally, my lamps lasted about 3 years too. About the time I noticed they were aging I was replacing them with LED.
 
Nutty sKunK

Nutty sKunK

Well-Known Member
ttystikk said:
Plants veg well under red or blue light, provided there's enough light and all other parameters are on point.

Therefore, check all of your other parameters; fresh nutes? Good EC and pH? Water temp (if applicable)? Air temps and humidity? Fall is here and a cooler growing space will slow metabolism. So will excess moisture or excess dryness. How about CO2? Closing up your apartment may mean it's depleted unless you're home breathing on them.

If all that is good, then it's your lights.

Personally, my lamps lasted about 3 years too. About the time I noticed they were aging I was replacing them with LED.
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All on point as per previous grows. 25-27c 60-66% humidity. Just planted in a light peat based potting mix and mycorrhiza added like always.

Another thing I’m noticing is the stems are stretching on 6 different strains. Deffo a symptom of light issues.

What did you notice about your aging lamps?
 
Rocket Soul

Rocket Soul

Well-Known Member
Nutty sKunK said:
All on point as per previous grows. 25-27c 60-66% humidity. Just planted in a light peat based potting mix and mycorrhiza added like always.

Another thing I’m noticing is the stems are stretching on 6 different strains. Deffo a symptom of light issues.

What did you notice about your aging lamps?
Click to expand...
Maybe more than one issue; but it seems like time to replace. In any case you should always have your next bulb spare handy so that you could check these things. If it just goes out one day what do you do? Wait for the new one or just screw it in straight away. If buying two bulbs both should be checked at purchase even if one is a spare. Id buy a new one just on the off chance and having a spare
 
Nutty sKunK

Nutty sKunK

Well-Known Member
Rocket Soul said:
Maybe more than one issue; but it seems like time to replace. In any case you should always have your next bulb spare handy so that you could check these things. If it just goes out one day what do you do? Wait for the new one or just screw it in straight away. If buying two bulbs both should be checked at purchase even if one is a spare. Id buy a new one just on the off chance and having a spare
Click to expand...
I do have an old hps/MH setup I could get out the attic but much more convenient with a new bulb lol

It’s a double ended fixture so two 315w bulbs. Will keep these as back up!
 
ttystikk

ttystikk

Well-Known Member
Nutty sKunK said:
All on point as per previous grows. 25-27c 60-66% humidity. Just planted in a light peat based potting mix and mycorrhiza added like always.

Another thing I’m noticing is the stems are stretching on 6 different strains. Deffo a symptom of light issues.

What did you notice about your aging lamps?
Click to expand...
Well since I was going for stretch that didn't bug me lol

My CMH lamps were pretty blue; my 860W (1000W on 240V) CDM lamps were about 3850K color temp and my 315WCMH (same tech, different name) were either 4000 or a touch over. I ran them with 600W HPS, they worked fine for me. LED was better in every way.
 
tstick

tstick

Well-Known Member
When I first bought my Hydrofarm 400 watt magnetic ballast light back in the 80's, the bulbs were expensive, so I kept using the same one for a long time. The bulbs definitely lose brightness as they age. It may appear subtle and you might not notice it. That's why, whenever I use my MH fixture (which still works flawlessly, btw), I get the cheap, single-ended Sylvania generic bulbs for ~$25 each. I run an unshielded reflector so I get ALL the UV and IR it can put out. I sometimes run it in the cold months because it heats the tent very well on its own! I like to change the bulb each year....seems like a waste, but they really do fall off in terms of light output....while still drawing the full 400 watts from the wall!
 
Wastei

Wastei

Well-Known Member
Nutty sKunK said:
Thats what I’ve seen quoted just wanted some personal experience from it.

My bulbs have only done between 10-12k hrs
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It's important to note that those numbers are calculated using a magnetic ballast. Running digital ballast will shorten lifespan and output going from years to grows.
 
Nutty sKunK

Nutty sKunK

Well-Known Member
Wastei said:
It's important to note that those numbers are calculated using a magnetic ballast. Running digital ballast will shorten lifespan and output going from years to grows.
Click to expand...
Oh really? Thats good to know! Mine is running a digital ballast. Seems like one bulb has been impact more than the other
 
Rocket Soul

Rocket Soul

Well-Known Member
Wastei said:
It's important to note that those numbers are calculated using a magnetic ballast. Running digital ballast will shorten lifespan and output going from years to grows.
Click to expand...
Is that for all digitals? I remember something about square wave something but im a led guy
 
ttystikk

ttystikk

Well-Known Member
Rocket Soul said:
Is that for all digitals? I remember something about square wave something but im a led guy
Click to expand...
LFSW = Low Frequency Square Wave ballasts are ideal for CMH lamps, providing some 30% more light while preserving lifespan.

Old school high frequency digital ballasts - the kind that piss off cable providers- are absolutely not recommended for CMH lamps.
 
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