420 Magazine Background

315Watt CMH Lighting: Specs, Coverage, Pics

Do you think CMH is a viable alternative to LED?

  • Yes

    Votes: 36 70.6%
  • No

    Votes: 5 9.8%
  • I need to read more.

    Votes: 7 13.7%
  • Isn't a Poll a sheep.

    Votes: 3 5.9%

  • Total voters
    51

kentboy1296

Well-Known Member
BEAUTIFUL mate, i think i may switch to coco, but for now im running both White Widow and Super Silver Haze in five gallon buckets 1st indoor grow using some shitty blurpies ( next run will be 600watt MH/HPS in a 5ft by 5ft by 7ft tent, using the LEDs to keep my mothers and clones going heres my set up, no bud yet
1795927
 

Grassmaster

Well-Known Member
Ya know, as much as I’m keen to pull the trigger on some CMH lighting, I’ve been out reading through articles on CMH for a couple years now, and they always cite the same info about it being inferior to HPS in flowering, due to HPS having a better red spectrum. If it was just a couple websites saying this I could chalk to up to outdated misinformation. But no, this is pretty much every current article I read on the topic. Hard to just ignore it, and I don’t have a pet lighting expert to ask about this. I wish I did. But the net is my only source of info. So what gives? :hmmmm:
FACTS

Their are some on this site that say they get better yield with a CMH instead of the HPS. HPS isn't good for young plants so you also will have to use a Metal Hylide. CMH is also a little more efficient than HPS. A bulb is also available for CMH that has more of a FAR RED light. Bulbs last much longer in a CMH.

Cob's are better. With cob's I get as good or better potency. Less wattage for more light. Product has a sweet herbal smell. In my 3' by 3' I can easily get over 1000 PAR everwhere on the tops of the plants with better penetration. With CMH I have to be careful of getting the light too close as it will raise temperatures (a srong fan will have to be used. And the PAR drops off quickly when I mover the light meter towards the edge of the tent. Temperatures can be allowed to go up further with cob's because they don't transmit much added heat (infa red) to the plants.
 

Lowrider72

Well-Known Member
You could get a remote cmh ballast and parabolic reflector with an adapter for a single-ended cmh bulb. That would mitigate the heat away from the canopy - if you choose a reflector with vent holes in the top - and also allow the light to be lower.
For Grassmaster.... Always the heat thing.

But the Quantum board or Cob has an efficiency of 2.0 and the CMH only (1.3). And the CMH radiate heat which isn't good unless you have cold weather. You waste even more money on air conditioning.

So in the long run you will pay more for the CMH.

I use my CMH only when it is very cold. Then switch over as soon as possible.
My ballast runs 97% efficiency, 1.72uMols per watt. Tested in REAL labs.
The broad reflectors I use are brilliant, let heat escape so if you have filter at top of tent...where it should be, its extracted straight out...
I run full spectrum 6500K LED for mums and clones etc, not against LED.

BEAUTIFUL mate, i think i may switch to coco, but for now im running both White Widow and Super Silver Haze in five gallon buckets 1st indoor grow using some shitty blurpies ( next run will be 600watt MH/HPS in a 5ft by 5ft by 7ft tent, using the LEDs to keep my mothers and clones going heres my set up, no bud yet
1795927
They look Awesome mate! If your doing DWC stick with it, it yields better than coco once you get it dialled. Coco is just easier for me.
You could run that area with one 630w CMH or two 315w and it would crank.
One bulb lasts 15000hours... Hps...5000hrs...

FACTS

Their are some on this site that say they get better yield with a CMH instead of the HPS. HPS isn't good for young plants so you also will have to use a Metal Hylide. CMH is also a little more efficient than HPS. A bulb is also available for CMH that has more of a FAR RED light. Bulbs last much longer in a CMH.

Cob's are better. With cob's I get as good or better potency. Less wattage for more light. Product has a sweet herbal smell. In my 3' by 3' I can easily get over 1000 PAR everwhere on the tops of the plants with better penetration. With CMH I have to be careful of getting the light too close as it will raise temperatures (a srong fan will have to be used. And the PAR drops off quickly when I mover the light meter towards the edge of the tent. Temperatures can be allowed to go up further with cob's because they don't transmit much added heat (infa red) to the plants.
Lol. CMH are slightly more efficient than HPS.....Thats claptrap...
Try 50% MORE efficient and thats just through using a square wave inverter ballast.

PAR doesnt mean shit. uMol is the real measuring stick. Intensity of ALL lights drop off towards the edges of a grow area.

IR is part of the far Red spectrum and is needed in plant growth.

Honestly, maybe its your set up that lets you down, ventilation wise. Summer is Summer- I choose to shut down instead of push shit up hill with aircon for average results.
I use NO enviromental control and run 9mth to 10mths a year, usually 2 grows including drying time. Could knock out 3 with seperate drying area.
If thats not enough, dont know what is....
My WHOLE Veg and Flower room, both tents draws under 800w....flat out. Including all fans etc.
I have seen some amazing cob and LED grows but with months of training.... I veg for 4 weeks.
And how many cobs for 4' x 4'? Watts?
Im at 315 watts in that area 550 uMols.
 

LiberalThinker

Well-Known Member
PAR doesnt mean shit. uMol is the real measuring stick. Intensity of ALL lights drop off towards the edges of a grow area.
That's inverse square law and no light source, not even the Sun, can escape it. A photon from an LED is no different to one from any other light source. If one light spreads the light more evenly to the edges over another that's a function of its reflector or layout and not the light type.
 

LiberalThinker

Well-Known Member
FACTS

Their are some on this site that say they get better yield with a CMH instead of the HPS. HPS isn't good for young plants so you also will have to use a Metal Hylide. CMH is also a little more efficient than HPS. A bulb is also available for CMH that has more of a FAR RED light. Bulbs last much longer in a CMH.

Cob's are better. With cob's I get as good or better potency. Less wattage for more light. Product has a sweet herbal smell. In my 3' by 3' I can easily get over 1000 PAR everwhere on the tops of the plants with better penetration. With CMH I have to be careful of getting the light too close as it will raise temperatures (a srong fan will have to be used. And the PAR drops off quickly when I mover the light meter towards the edge of the tent. Temperatures can be allowed to go up further with cob's because they don't transmit much added heat (infa red) to the plants.
FACTS: Phillips HPS bulbs from the 90's to now, grow plants from seedling to flower just fine and am currently burning a Philips Green Power 600w at 250w and the little plant is happy. MH is not absolutely necessary. I'll be using a 315 CMH next week when a reflector for it comes, so will be able to comment on that eventually but looking at the spectrum it looks to be an excellent fusion of MH and HPS.
 

Lowrider72

Well-Known Member
Thank you Yellowbelly, I had a shit morning, renewed my faith in common sense. Hahaha.
Im with you on the Philips green ,thats the successor to the Philips Son T pia, the best HPS globe I ever used.
I have used 3 of those in a 4' x 8' and smashed 4 1/2 pound out of it.
ummm....bit over 2kg.
But the power bills...ouch! Lol

You are not going to be dissapointed by CMH, they kick arse. Save on power without scrimping on quality of light.
Enough heat to run 3/4 year with no enviromental conditioning to pay for.

The growth is amazing, health of plants is crazy, even in flower.
Even canopy is essential, Im missing out on good light lower using un trained plants, because as you can see... The top colas go a lil large....and I really would,like the light lower over them to pump the second tier of buds....next round.

May take 1 grow to get the hang of lowering them more than hps and the canopy will help a lot.
Just a couple observations.


WP_20190512_20_37_15_Rich_LI.jpg
 

TheFertilizer

Well-Known Member
Ya know, as much as I’m keen to pull the trigger on some CMH lighting, I’ve been out reading through articles on CMH for a couple years now, and they always cite the same info about it being inferior to HPS in flowering, due to HPS having a better red spectrum. If it was just a couple websites saying this I could chalk to up to outdated misinformation. But no, this is pretty much every current article I read on the topic. Hard to just ignore it, and I don’t have a pet lighting expert to ask about this. I wish I did. But the net is my only source of info. So what gives? :hmmmm:
I think the problem is it's one of those things that someone says, and then people say it because they think it sounds right, and then the next thing you know it turns into something that's gospel. But is it fact? I don't know of any side-by-side comparisons that are referenced, or even any at all to look at. The problem is that no one has really done it controlled, you know with clones, same grow media etc. There's tons of anecdotal evidence of people that say they think they yielded more or less from CMH, but I think the reason that all the grow sites say that HPS still gets better yields is for the simple fact that CMH growers are trying to compare the CMH levels at 630 W with HPS at 1000 W and they're simply not equivalent. But in addition to that, I think most places just tend to copy cat that type of information and so unless you see some actual data showing otherwise, I wouldn't believe it. You're definitely not going to yield as much with a 630 W CMH as with a 1000K W HPS, but you will match the yield of a 600 W HPS and have better quality to boot.

The reason just comes down to PAR. I'm sure you're familiar. Lumens mean nothing. PAR is what the plant wants, etc. But what is the best PAR? Well, as far as I'm aware, the McCree curve.

The McCree curve & HPS vs CMH for flowering - Help!

I think HPS still has its place but if your goal is better light quality and energy efficency, CMH is definitely the way to go. As for CMH vs LED, I don't think the answer is quite so clear. I think LEDs are technically able to get better quality light since you simply have more control over the spectrums available, but as far as the price-point, reliability and other factors go, I think CMH is far simpler to get into.

If you want to look around at my journals, my Panama x Malawi was grown with both HPS and CMH. The grow media changed though, so I don't think the yields are comparable, but you can take a look at the bud growth of the CMH vs the HPS.
 

Grassmaster

Well-Known Member
Lol. CMH are slightly more efficient than HPS.....Thats claptrap...
Try 50% MORE efficient and thats just through using a square wave inverter ballast.

PAR doesnt mean shit. uMol is the real measuring stick. Intensity of ALL lights drop off towards the edges of a grow area.
In the video below you will see the facts. 50%. Chuckle. PAR is a umoles measurement. And it doesn't matter what light meter you use COB's will come out on top.

 

kentboy1296

Well-Known Member
For Grassmaster.... Always the heat thing.


My ballast runs 97% efficiency, 1.72uMols per watt. Tested in REAL labs.
The broad reflectors I use are brilliant, let heat escape so if you have filter at top of tent...where it should be, its extracted straight out...
I run full spectrum 6500K LED for mums and clones etc, not against LED.


They look Awesome mate! If your doing DWC stick with it, it yields better than coco once you get it dialled. Coco is just easier for me.
You could run that area with one 630w CMH or two 315w and it would crank.
One bulb lasts 15000hours... Hps...5000hrs...


Lol. CMH are slightly more efficient than HPS.....Thats claptrap...
Try 50% MORE efficient and thats just through using a square wave inverter ballast.

PAR doesnt mean shit. uMol is the real measuring stick. Intensity of ALL lights drop off towards the edges of a grow area.

IR is part of the far Red spectrum and is needed in plant growth.

Honestly, maybe its your set up that lets you down, ventilation wise. Summer is Summer- I choose to shut down instead of push shit up hill with aircon for average results.
I use NO enviromental control and run 9mth to 10mths a year, usually 2 grows including drying time. Could knock out 3 with seperate drying area.
If thats not enough, dont know what is....
My WHOLE Veg and Flower room, both tents draws under 800w....flat out. Including all fans etc.
I have seen some amazing cob and LED grows but with months of training.... I veg for 4 weeks.
And how many cobs for 4' x 4'? Watts?
Im at 315 watts in that area 550 uMols.
Yea, thats the reason i got into dwc in the 1st place @Lowrider72 I HEARD faster growth and better yeilds once your dialed in... its just alot of waste water using an RO filter (1gal of ro = almost 4gal of waste water) trying to be stealthy but my landlord may see a water increase... How does just tap water work? I believe my ppm of my tap is right at 200 out the faucet
 

Grassmaster

Well-Known Member
FACTS: Phillips HPS bulbs from the 90's to now, grow plants from seedling to flower just fine and am currently burning a Philips Green Power 600w at 250w and the little plant is happy. MH is not absolutely necessary. I'll be using a 315 CMH next week when a reflector for it comes, so will be able to comment on that eventually but looking at the spectrum it looks to be an excellent fusion of MH and HPS.
Well I've never grown HPS so what you say is probably correct. Most of the grow info out there is obsolete and doesn't mention the newer bulbs.
 

LiberalThinker

Well-Known Member
Well I've never grown HPS so what you say is probably correct. Most of the grow info out there is obsolete and doesn't mention the newer bulbs.
If your climate doesn't exclude the heat from HIDs, I would say the likes of Philips and Eye Hortilux have that technology fully sussed now. Comparable LED systems are still megamoney, to me, but they will be affordable in the foreseeeable future.
 
  • Like
Reactions: 423

LiberalThinker

Well-Known Member
I think the problem is it's one of those things that someone says, and then people say it because they think it sounds right, and then the next thing you know it turns into something that's gospel. But is it fact? I don't know of any side-by-side comparisons that are referenced, or even any at all to look at. The problem is that no one has really done it controlled, you know with clones, same grow media etc. There's tons of anecdotal evidence of people that say they think they yielded more or less from CMH, but I think the reason that all the grow sites say that HPS still gets better yields is for the simple fact that CMH growers are trying to compare the CMH levels at 630 W with HPS at 1000 W and they're simply not equivalent. But in addition to that, I think most places just tend to copy cat that type of information and so unless you see some actual data showing otherwise, I wouldn't believe it. You're definitely not going to yield as much with a 630 W CMH as with a 1000K W HPS, but you will match the yield of a 600 W HPS and have better quality to boot.

The reason just comes down to PAR. I'm sure you're familiar. Lumens mean nothing. PAR is what the plant wants, etc. But what is the best PAR? Well, as far as I'm aware, the McCree curve.

The McCree curve & HPS vs CMH for flowering - Help!

I think HPS still has its place but if your goal is better light quality and energy efficency, CMH is definitely the way to go. As for CMH vs LED, I don't think the answer is quite so clear. I think LEDs are technically able to get better quality light since you simply have more control over the spectrums available, but as far as the price-point, reliability and other factors go, I think CMH is far simpler to get into.

If you want to look around at my journals, my Panama x Malawi was grown with both HPS and CMH. The grow media changed though, so I don't think the yields are comparable, but you can take a look at the bud growth of the CMH vs the HPS.
My mind is completely open on CMH. Philips don't claim their 315 CMH bulbs are better than 600 watters but they do say they are more productive than 400 watters and better quality. That's good enough for me. I'm used to 400w and single plants, so anything that improves on that suffices for me. I have a 600w dimmable HPS system as well, so will be able to compare eventually.
 

Lowrider72

Well-Known Member
In the video below you will see the facts. 50%. Chuckle. PAR is a umoles measurement. And it doesn't matter what light meter you use COB's will come out on top.

Well the figures he give are flawed, how is it he says cmh and lec is 1.29 uMol/watt when mine has been tested at 1.72 uMol/watt.
Some pissy little meter is not a light test.
Go online like the good little video watcher you are and look at Gavitas test area for lighting and you will find handheld meters are a joke.

And yes, a 315cmh is 50% more efficient than hps at 600w. Can cover the same area just as well.
Im totally in agreement with Fert.
 

LiberalThinker

Well-Known Member
Yea, thats the reason i got into dwc in the 1st place @Lowrider72 I HEARD faster growth and better yeilds once your dialed in... its just alot of waste water using an RO filter (1gal of ro = almost 4gal of waste water) trying to be stealthy but my landlord may see a water increase... How does just tap water work? I believe my ppm of my tap is right at 200 out the faucet
200ppm is nothing to worry about; use it. Mine's 300 - 350ppm. I ph my water first to 5.5 -5.8 with nitric acid, before adding GH nutes, and that converts the hardwater calcium to plant-usable calcium nitrate, My final pH stays in that zone, so it isn't necessary to pH again after adding the nutes. Use hard water version of whatever nutes you use and forget about it.
 

LiberalThinker

Well-Known Member
Well the figures he give are flawed, how is it he says cmh and lec is 1.29 uMol/watt when mine has been tested at 1.72 uMol/watt.
Some pissy little meter is not a light test.
Go online like the good little video watcher you are and look at Gavitas test area for lighting and you will find handheld meters are a joke.

And yes, a 315cmh is 50% more efficient than hps at 600w. Can cover the same area just as well.
Im totally in agreement with Fert.
Philips 315 are 1.9 uMol/sec
 
Last edited:

kentboy1296

Well-Known Member
200ppm is nothing to worry about; use it. Mine's 300 - 350ppm. I ph my water first to 5.5 -5.8 with nitric acid, before adding GH nutes, and that converts the hardwater calcium to plant-usable calcium nitrate, My final pH stays in that zone, so it isn't necessary to pH again after adding the nutes. Use hard water version of whatever nutes you use and forget about it.
Ok cool, thanks for the tip, if i let the water sit for a day or two with an airstone it drops a little bit. But thats what im gonna try then, cuz im running GH flora trio and just gotta order the hardwater. I feel much better trying it now thanks a bunch mate
 

LiberalThinker

Well-Known Member
Ok cool, thanks for the tip, if i let the water sit for a day or two with an airstone it drops a little bit. But thats what im gonna try then, cuz im running GH flora trio and just gotta order the hardwater. I feel much better trying it now thanks a bunch mate
Here's a schedule with it. There's 5ml to a teaspoon.

Recirculating-Nutrient-Schedule-custom.jpg

Ignore the flush part if you don't want to do that and halve the dosage of the 'ripen' row in the chart to finish off. To reduce the risk of deficiencies you could start your pH at 5.5 and the let it rise to 6. 3 before correcting it back down again... if it gets that far before a full change in water is due. The idea is that the pH will be optimal for each of the nutrient components at some point in time as it rises and you are not adding too much in the way of extra nutes with adding acid or alkali too often. The idea is to check it everyday but don't adjust everyday. You'll eventually get a feel for it and avoid over-fertilising, which is a very common problem.
 
Last edited:

bluenoserjoe

Photo of the Month: May 2019
Hi all. Just finished reading through this thread. Very interested as I currently have six dim-able Sun System using Phillips 3200k 315cmh bulbs. Love the dim-able system paired with this bulb, really allows lowering the light early on. Can't compare them with anything else as this is the first go around with them. As for final weight we shall see as this grow is in a 48 hour dark cycle as we speak.



 

LiberalThinker

Well-Known Member
315w Philips Master CDM Lamps

These state-of-the art lamps generate a greater level of useable plant light (photosynthetically active radiation) and run with a blinding intensity that's immediately apparent to the naked eye. The lamp is full-spectrum so it will produce the goods in both veg and flower – expect to see increased growth rates, tighter internodes, an improvement in overall vigour and an increase in final weight. It also has an increase in the red spectrum which gives a definate boost during flowering.

Philips GreenPower 930 Elite Agro CDM Lamp – full spectrum lamp with an increased red spectrum
Philips MasterColour 942 Daylight CDM Lamp – full spectrum lamp with extra blue light for veg
Run at blinding intensity that's clearly visable with the naked eye
Ideal to give your plants a boost during flowering to increase yields
Highly efficient Philips 930 Agro puts out 1.9 micromole (umol) per watt of electricity
Highly efficient Philips 942 Daylight puts out 1.7 micromole (umol) per watt of electricity
Extremely high PAR levels on both lamps

 
Top Bottom