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LED vs CMH; Which is better and does the PAR difference really mean anything?

  • Thread starter Thread starter RikkiTikkiTemb0
  • Start date Start date Oct 29, 2023
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LED vs CMH; Which is better and does the PAR difference really mean anything?

RikkiTikkiTemb0 Oct 29, 2023 5 Replies 7,131 Views
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RikkiTikkiTemb0

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#1
So I have exhausted my contacts in regards to this question and the answers so far have felt uninformed and certainly not scientific/empirical in the slightest

Firstly, Does CMH really have a better PAR and/or PPFD than LED, is it the other way around, or is there no difference and it only lies in the quality/design of the product (which Diode and processor for LED and Which Ballast has which Bulb for CMH)?

As far as I've seen CMH ALWAYS has a higher PAR in every regard PLUS an extended UV and IR spectrum (UV very important for trichome development I've heard and read) but is the difference really consequential or measurable? Moreover, I have heard that the extra UV just isn't needed and that even if you supplement with far blues you're just increasing your chance of burning the plant... is this true? Ive read in a study (published by Frontiers) the opposite of this and the more light and UV present (PPFD) has a linear correlation to an increase in the presence of terpenes and actual volume of flower. The study in question claimed that the highest this correlation goes is a PPFD of 1,800 umol which sounds very high to me given everything else I've read which says 1,000-1,200 umol for bulk flower is standard.

This brings me to my second concern/point of contention; I have been told that the Wattage claimed by LEDs is different from that which is claimed by CMH. How can this be the case? Is there some weird sales trick which instead of calculating the Watts consumed over, say, 3hrs for LEDs the CMHs are calculated at the Watts consumed in 1hr? The SunSystem LEC/CMH boasts a 315W consumption which would be standard unit W/h... right? Is this different from an LED which is labeled at 315W (aka 315W/hr), is the time the Watt consumption is measured different?

Now assuming that there is no weird salesmen trickery, and the Wattage labeled is measured at the same unit/rate, surely this doesn't effect the cost outside of having to buy bulbs right? I know that question may seem obvious but again I'm hearing a lot of conflicting ideas and there's, unfortunately, no place that I know of that has this comprehensive of a comparison that isn't from a store/blog/interested party trying to push a product. I need hard evidence as best as possible (well informed anecdotes are welcome, but none of this "some people say" bc I want to know who specifically is saying this and whether they have credible ethos)

I know this is a long and involved post, but I would research this myself if I was able to find more concrete evidence. Thank you and I await your detailed response.

Study mentioned; https://www.frontiersin.org/articles/10.3389/fpls.2021.646020/full
 
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jonesfamily7715

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#2
Cmh is superior to 95% of led out there even watt for watt in my opinion but new led advancements have been crazy in the past couple years and there are company's with these missing ir and uv spectrum, check out the lights from growlightsaustralia. The wattage difference your hearing about is probably led equivalent ratings which were complete bullshit marketing scam %100, if your on the fence about which to go with just think of how much has changed In the past couple years with led if you woulda bought top of the line fixtures 3 years ago, you would be regretting it now, it wouldn't be anything special by today's standard, that cmh is still the same proven technology which does very very well at a modest price.
 
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3cats

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#3
RikkiTikkiTemb0 said:
So I have exhausted my contacts in regards to this question and the answers so far have felt uninformed and certainly not scientific/empirical in the slightest

Firstly, Does CMH really have a better PAR and/or PPFD than LED, is it the other way around, or is there no difference and it only lies in the quality/design of the product (which Diode and processor for LED and Which Ballast has which Bulb for CMH)?

As far as I've seen CMH ALWAYS has a higher PAR in every regard PLUS an extended UV and IR spectrum (UV very important for trichome development I've heard and read) but is the difference really consequential or measurable? Moreover, I have heard that the extra UV just isn't needed and that even if you supplement with far blues you're just increasing your chance of burning the plant... is this true? Ive read in a study (published by Frontiers) the opposite of this and the more light and UV present (PPFD) has a linear correlation to an increase in the presence of terpenes and actual volume of flower. The study in question claimed that the highest this correlation goes is a PPFD of 1,800 umol which sounds very high to me given everything else I've read which says 1,000-1,200 umol for bulk flower is standard.

This brings me to my second concern/point of contention; I have been told that the Wattage claimed by LEDs is different from that which is claimed by CMH. How can this be the case? Is there some weird sales trick which instead of calculating the Watts consumed over, say, 3hrs for LEDs the CMHs are calculated at the Watts consumed in 1hr? The SunSystem LEC/CMH boasts a 315W consumption which would be standard unit W/h... right? Is this different from an LED which is labeled at 315W (aka 315W/hr), is the time the Watt consumption is measured different?

Now assuming that there is no weird salesmen trickery, and the Wattage labeled is measured at the same unit/rate, surely this doesn't effect the cost outside of having to buy bulbs right? I know that question may seem obvious but again I'm hearing a lot of conflicting ideas and there's, unfortunately, no place that I know of that has this comprehensive of a comparison that isn't from a store/blog/interested party trying to push a product. I need hard evidence as best as possible (well informed anecdotes are welcome, but none of this "some people say" bc I want to know who specifically is saying this and whether they have credible ethos)

I know this is a long and involved post, but I would research this myself if I was able to find more concrete evidence. Thank you and I await your detailed response.

Study mentioned; https://www.frontiersin.org/articles/10.3389/fpls.2021.646020/full
Click to expand...
I used HPS for 20+ years, I was gifted an led light and after my 1st grow with a 300watt led light I bought 2 more and jumped right into led's. I still have ballasts and lamps with a few large reflectors sitting in the corner unused now. The only time I miss my HPS is in the dead of winter when I can use the heat but the rest of the year its Led's for the win imho
 
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RikkiTikkiTemb0

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#4
jonesfamily7715 said:
Cmh is superior to 95% of led out there even watt for watt in my opinion but new led advancements have been crazy in the past couple years and there are company's with these missing ir and uv spectrum, check out the lights from growlightsaustralia. The wattage difference your hearing about is probably led equivalent ratings which were complete bullshit marketing scam %100, if your on the fence about which to go with just think of how much has changed In the past couple years with led if you woulda bought top of the line fixtures 3 years ago, you would be regretting it now, it wouldn't be anything special by today's standard, that cmh is still the same proven technology which does very very well at a modest price.
Click to expand...
This what ive been reading and have read for as long as I have known about CMH/LEC but these LED loyalists swear up down and sideways by their LEDs. I will take a look at growlightsaustralia (good shout, cheers for that). I did do some looking into the diodes and it seems Samsung is king, especially the left over ones that havent gone to TVs, would you vouch for this claim or not so much?
 
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RikkiTikkiTemb0

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#5
3cats said:
I used HPS for 20+ years, I was gifted an led light and after my 1st grow with a 300watt led light I bought 2 more and jumped right into led's. I still have ballasts and lamps with a few large reflectors sitting in the corner unused now. The only time I miss my HPS is in the dead of winter when I can use the heat but the rest of the year its Led's for the win imho
Click to expand...
Yeah I think HPS is going the way of the dinosaur, it hasn't even been a type of light I considered for my grow. Do you know anything about LEC/Ceramic Metal Halide?
 
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Cannaburg

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#6
RikkiTikkiTemb0 said:
Yeah I think HPS is going the way of the dinosaur, it hasn't even been a type of light I considered for my grow. Do you know anything about LEC/Ceramic Metal Halide?
Click to expand...
Here is what I used for a decade..
I made the switch over a year ago..
I have hps..mh... and plasma lighting... im waaaaaaay happier with my phlizon fd6500 and medic grow ez8 leds
 

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Started Oct 29, 2023
Latest post Oct 30, 2023
Starter RikkiTikkiTemb0
Forum Growroom Design & Setup

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