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cmh penetration vs hps

9

967

Active member
hi people, can't really find anything specific to vert on this subject, but i usually run a single 600W HPS with a 250w MH supplementary lighting and do ok - 4x4 tent (best was a touch under 22)

Thinking about making the switch to cmh but its ultra costly here in my neck of the earth ($620), which im prepared to pay if worth it, Just not sure about the penetration compared to 600W hps? Cant get any dual ballasts here either so thats out of the question or i would just run two 315w's

heat is always a slight issue and the plants usually get upset at first when introduced to much more intense light combined with a lot more heat (compared to when just under 250w MH). Thinking CMH might be the way to go to reduce such side effects...


Thoughts?

Basically i guess the question here is; Will a 315W CMH penetrate and spread light as well or better than a 600W HPS in a 4x4 vert setup? With less heat?

Cheers
 
R

Rab.C

hi there i have bought an adjustAwing hellion 315cmh and i am about too set it up
i was told the dont penetrate the canopy as good as 600watts
sorry i cant help you but there lots of people here using cmh so you should get the answers
your looking for all the best Rab
 
zachrockbadenof

zachrockbadenof

Well-known member
Veteran
i run '2' 315's with philips bulbs in a 4x3.5 tent - i have not run a 600w, but have run 1000w (in a room) and my feelings are the 2 315's i am running is not enough light, and the penetration is weak... if i can get a handle on the heat, next grow i will use the 1000w.. various opinions i read is that a 315 is equal to a 400w hps (some even say more)- i don't think so...
 
944s2

944s2

Well-known member
ICMag Donor
Veteran
zachrockbadenof said:
i run '2' 315's with philips bulbs in a 4x3.5 tent - i have not run a 600w, but have run 1000w (in a room) and my feelings are the 2 315's i am running is not enough light, and the penetration is weak... if i can get a handle on the heat, next grow i will use the 1000w.. various opinions i read is that a 315 is equal to a 400w hps (some even say more)- i don't think so...
Click to expand...

Hey zach,
I was told ,
,pretty much like you posted that a 315 puts out 520! and only half the heat ,,lol
These cmh units are expensive so the shops have to try and move them so a over exaggerated power output would look very attractive,
If you were not “ clued up “,,,
Naughty sales assistants :),,,s2
 
I'mback

I'mback

Comfortably numb!
zachrockbadenof said:
i run '2' 315's with philips bulbs in a 4x3.5 tent - i have not run a 600w, but have run 1000w (in a room) and my feelings are the 2 315's i am running is not enough light, and the penetration is weak... if i can get a handle on the heat, next grow i will use the 1000w.. various opinions i read is that a 315 is equal to a 400w hps (some even say more)- i don't think so...
Click to expand...
Although this link https://www.youtube.com/channel/UCSZwj4zGhH1yklVFxS54qdA "Migro" may seem biased, I found their comparative testing (using instruments) beneficial. e.g comparing apples to apples. Read the test data vs having preconceived decisions.

Folks say that LEDs do not pull "actual watts" from the wall. I would like to know what kind of watts they pull. LED watts? LEDs in general pull less than incandescent bulbs. e.g 23w equivalent to 60w, nearly consumes 1/3 less power. I guess the point of discussion should be how are they determining this?

That being said, not all apples are created equal and would I trust specs coming out of China? Absolutely not! But, the technology is heading in the right direction and, humans do not like change. It's coming around though and time to get on the bus or get left behind. ~ The future is bright, I gotta wear shades "biggrin:
 
R

Rab.C

944s2 said:
Hey zach,
I was told ,
,pretty much like you posted that a 315 puts out 520! and only half the heat ,,lol
These cmh units are expensive so the shops have to try and move them so a over exaggerated power output would look very attractive,
If you were not “ clued up “,,,
Naughty sales assistants :),,,s2
Click to expand...

think it comes down too the shop 944s2 i switched too 315cmh
because he said i would get less yield than a 400watt hps.but the
buds would be of a better qualty.and i was wanting less heat.so for
me in winter 2 x 315cmh would be great heat wise
 
I'mback

I'mback

Comfortably numb!
Great find Fred :) What about the Dark side of the moon? There will always be shadows where light doesn't penetrate. Would work on a rotating grow though :)
 
dank.frank

dank.frank

ef.yu.se.ka.e.em
ICMag Donor
Veteran
I run 2 x 315 in a 2.5' wide x 5' long room. Organic soil bed. Nothing but water. Pulled right at 20 with 3 plants from seed. First run in over 5 years.

Running 8 this round, I expect I'll come closer to 2 with proper canopy management.

If you read my posts in the various CMH threads, or just breeze through my thread, the penetration of the lights was one of my biggest concerns. They aren't a 1k and you shouldn't expect 1k numbers. They do, however, absolutely crush an old 400w HPS, my opinion.

I say 14" is the peak of their penetration through a dense canopy. Below that, the flowers start getting a bit more open. You can go to about 18-20" and safely have no real larf, but you'll have some smaller nugs most would toss into the trim bin. Those flowers produced though, do not look like flowers grown from small wattage bulbs. They look every bit comparable to 1k flowers in quality. I never thought I'd say this, but it's the truth.

This pic was last round at 59 days - but was taken for the exact purpose of showing penetration of the lamps and the density of the flowers produced. The colas in the picture are about 11-13".

picture.php



I went with Growers Choice all in one units with 3100k red enhanced bulbs. Very glad I made the upgrade for the new grow.

I know this question was addressed for a vertical setup, but 14" is 14" regardless the direction the light is moving, I figure.



dank.Frank
 
I'mback

I'mback

Comfortably numb!
dank.frank said:
I run 2 x 315 in a 2.5' wide x 5' long room. Organic soil bed. Nothing but water. Pulled right at 20 with 3 plants from seed. First run in over 5 years.

Running 8 this round, I expect I'll come closer to 2 with proper canopy management.

If you read my posts in the various CMH threads, or just breeze through my thread, the penetration of the lights was one of my biggest concerns. They aren't a 1k and you shouldn't expect 1k numbers. They do, however, absolutely crush an old 400w HPS, my opinion.

I say 14" is the peak of their penetration through a dense canopy. Below that, the flowers start getting a bit more open. You can go to about 18-20" and safely have no real larf, but you'll have some smaller nugs most would toss into the trim bin. Those flowers produced though, do not look like flowers grown from small wattage bulbs. They look every bit comparable to 1k flowers in quality. I never thought I'd say this, but it's the truth.

This pic was last round at 59 days - but was taken for the exact purpose of showing penetration of the lamps and the density of the flowers produced. The colas in the picture are about 11-13".

View Image


I went with Growers Choice all in one units with 3100k red enhanced bulbs. Very glad I made the upgrade for the new grow.

I know this question was addressed for a vertical setup, but 14" is 14" regardless the direction the light is moving, I figure.



dank.Frank
Click to expand...
I buy that as light is not affected by gravity :tiphat:
 
L

Leaflet

Active member
I'mback said:
Folks say that LEDs do not pull "actual watts" from the wall. I would like to know what kind of watts they pull.
Click to expand...

You either misheard or they told it wrong. They aren't advertised with "actual watts."
Here's the deal:
Good LED manufacturers tell you the actual watts their lights draw.
Not-so-good (like the no-name Chinese blurple lights that are all over Amazon) LED manufacturers will (for example) call a light a "600W."
Note that it says "W" and not "watt." Further down in the ad, you will see that it says proudly, "Only draws 108 watts!"

The way they come up with the deceptive "600W" is this:
If the light has 60 LED bulbs with a potential (which is never even close to realized) of 10 watts each... 60*10 = 600, which is how they come up with the name 600W. In reality those LED bulbs are drawing 1.5 watts each.
 
H

Horselover Fat

Member
Veteran
Leaflet said:
Not-so-good (like the no-name Chinese blurple lights that are all over Amazon) LED manufacturers will (for example) call a light a "600W."
Note that it says "W" and not "watt." Further down in the ad, you will see that it says proudly, "Only draws 108 watts!"
Click to expand...

W is the symbol for watt.
 
B

Blueback

New member
315's aren't the best penetrating light but I run 2 on a 4'x4' with a 4' 6 bulb T5 for side lighting. Works out great rock solid nugs from top to bottom. The resin production can't be beat.
 

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Lost in a SOG

Lost in a SOG

GrassSnakeGenetics
There are a lot of garbage low wattage diode poor penetration led rigs out there just shifting yesteryears tech afap.

After looking at cmhs with a par meter i sidelined them,, the light spread is just too uneven for my liking, a bit too intense just off center and too weak around the edges. Still much better quality than hps ever produced for me though.
 
SuperBadGrower

SuperBadGrower

Active member
The hps vs cmh discussion is almost worthless because HPS systems are different. The best hps system is >50% better than the worst one!

CMH elite agro: 1.44µmol/j
CMH 4100K: 1.34µmol/j
400w HPS (Sunlight Supply): 0.93-1 µmol/j
1000w HPS (sunlight supply, parsource): 1.02-1.15 µmol/j
1000w PARsource GLXII 1000w: 1.3 µmol/j
Gavita Pro, ePapillon 1kW: 1.7 µmol/j

Sources: Nelson, Jacob A. and Bugbee, Bruce, "Supplemental greenhouse lighting: Return on Investment for LED and HPS fixtures" (2013). Also: "Economic analysis of greenhouse lighting: light emitting diodes vs. high intensity discharge fixtures" (2014).


So if a 1000w DE could be dimmed down to 315w without losing efficacy it would still put out more light than a CMH. Yet the CMH absolutely dumps on the 400w magnetic HPS.

Penetration.... well.. If you take the lens off of a flashlight and shine it into the woods you're not going to see very far away. If you put the lens back on and shine it again you get a beam of light that reaches very far. The reflectors do the same. You increase the "penetration" by either increasing a light's power or changing the shape of the reflector / lens... Or, if you have multiple light sources, density equals intensity (i.e. COB led). If the sun had a giant reflector orbiting it we would be fucked.

The other thing about a light that might influence its "penetration," at least in plant terms, is the amounts of green and far red light which penetrate the canopy more easily than B/R. And what does HPS happen to have that CMH doesnt? (1) a 490-500nm peak (2) a majority of light in 560-590nm. Finally the peak at 830nm is bigger than CMH but afaik there is no evidence that this translates to better plant growth. (While there is evidence for 730nm supplementation)

if you look at it this way, it seems logical that a HPS system is the best if you are growing tall plants and concerned about quality of lowers. it has a very deep reaching spectrum. A blue/red LED would have relatively poor penetration.
 
H

Horselover Fat

Member
Veteran
Relative distance and the inverse square law should be taken into account too. Light A puts out X lumens at 50cm and light B produces the same X lumens at 25cm. The tops of the plants are 50cm and 25cm from the lamps respectively, and recieve the same ammount of lumens. One meter down from light A lumen count drops to 1/4X while for light B 1/4X is already at 50cm.
 
SuperBadGrower

SuperBadGrower

Active member
O yeah, that is important to keep in mind too, I completely forgot it. If there was 5000w hps and you managed to hang it so high that the tops get 1000 PAR you would still have really intense light at the ground.

that subject gets mostly interesting with LEDs where you can spread the power over an area easily. You can distribute 200w in such a way that your plants need to be 5cm close to the light. It would have to be a pretty big grow light with lots of small leds.

Regardless, what you said is completely true also between HID sources. I guess you could say that theoretically a CMH penetrates better and worse than a magnetic 400w HPS; better because it emits more light and is more intense, but marginally worse by spectrum (very hard to test this as a hobby grower of course)*. The 600w and 1000w HPS systems probably beat CMH on penetration with their intensity alone.

*of course the cmh has an objectively better spectral quality to humans and probably plants too, just talking about canopy penetration here
 
H

Horselover Fat

Member
Veteran
Yes, and then there are reflective walls and so many other things. There should be more studies and actual measurements to find out how things really work.

Different grow styles also have different requirements. Someone who grows trees in a warehouse needs different lighting than a closet scrogger. People often just think about their own grow and what suits it, without realizing that someone else has different needs... And endless arguments about the best lights ensue :biggrin:
 
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