Ceramic Metal Halide (CMH)

[amoril]

What do you mean the HPS bud was puffed up and not natural?? How could a light make the bud become "Unnatural?"

Also, what do you mean the CMH should put the plant back to it's natural native state of light spectrum? That doesn't make sense, am I misunderstanding you?

My understanding is the only real difference between a CMH and HPS is that the CMH gives off more light that is usable to a plant in terms of photosynthesis, so it emits fewer lumens, but a higher percantage of it's emitted light is usable to a plant.

I agree with the portions I didn't quote....and just wanna give my on this piece

When I refer to CMH being a more "natural" indoor lighting choice, Im referring to the spectrum of light emitted. The sun, what we would define as THE natural lighting source (duh) emits light in all spectra.

A HPS or MH bulb only emits appreciable quantities of light in a limited spectra, whereas a CMH throws a relatively full and somewhat balanced spectrum.

The reference to "puffed up" is probably an observational property of the fact that the plant is only recieving half the spectrum, and as such not stimulating all of the photosynthetic processes.

Bud grown under a HPS will be hard pressed to even resemble outdoor grown bud, but CMH buds seem to be more in line with natures bud/leaf ratio and structure.

 

[etinarcadiaego]

I agree with the portions I didn't quote....and just wanna give my on this piece

When I refer to CMH being a more "natural" indoor lighting choice, Im referring to the spectrum of light emitted. The sun, what we would define as THE natural lighting source (duh) emits light in all spectra.

A HPS or MH bulb only emits appreciable quantities of light in a limited spectra, whereas a CMH throws a relatively full and somewhat balanced spectrum.

The reference to "puffed up" is probably an observational property of the fact that the plant is only recieving half the spectrum, and as such not stimulating all of the photosynthetic processes.

Bud grown under a HPS will be hard pressed to even resemble outdoor grown bud, but CMH buds seem to be more in line with natures bud/leaf ratio and structure.

No that makes sense. I've seen outdoor bud here and a couple of times in real life and noticed it's much leafier than the indoor I've seen. Thanks for the explanation!

 

[onegreenday]

Thanks Amoril. Exactly my thoughts.
We tuned bro...........

 

[onegreenday]

The Pl Light Systems comes next week
and I'll test for lumen output.
More CMH lumens more plants growth.
EDIT: if i go from 1800 to 2400 footcandle;
lumens matter.

Edit: My plan is 3 400's side by side to equal
a 1k horty in output or about .5 gram per watt
would be fine 4 me.

 

[onegreenday]

etinarcadiaego : A 400 watt HPS puts out 49,000 lumens, whereas a 400 watt CMH emits only 31,000 lumens, yet we all agree is a more effective light despite the reduced lumen count. Lumens mean nothing when it comes to how much light is used by a plant for photosynthesis. END

The HPS plants weigh more ; the CMH plants weigh less;

same clones. The CMH makes more

leafy growth and buds r different too.

More lumens ;more weight I think is still
the accepted truth.

 

[etinarcadiaego]

Hmm. Lumens mean nothing to plants. Which is why, EVEN THOUGH CMH has fewer lumens I feel it grow comparable weight. You say less weight, well that's alright too.


Regardless man, lumens mean nothing to plants. It's all about wavelength

 

[hoosierdaddy]

It's all about wavelength

Spot on...
but let's not forget that the plant must have the proper atmosphere, food source, and root zone, for the light energy to have a chance to do it's work and transform all of those into the optimum smokable bud.
Any one of those out of whack, and it's not a fair judge of the others.

 

[knna]

An optical watt (emitted light) of CMH only produces 285lm, vs 385lm of a typical HPS. So, its not the HPS emits more light, but more lm: the light they emits produces an higher brightness sensation for human, but not for plants.

1000lm of CMH (4200K) holds near 16 micromols of photons. While 1000lm of HPS holds 11.5-12uE.

So 31000lm of CMH=496uE

49000lm of HPS=563 to 588uE.

So, the HPS emits more photons, but there is way less difference than lm rating leads to think.

 

[etinarcadiaego]

Spot on...
but let's not forget that the plant must have the proper atmosphere, food source, and root zone, for the light energy to have a chance to do it's work and transform all of those into the optimum smokable bud.
Any one of those out of whack, and it's not a fair judge of the others.

Very true. Growing indoors seems to be all about maintaining a balance between each of the factors, and many of them are trade offs.

Good point though!

 

[hoosierdaddy]

...So, the HPS emits more photons, but there is way less difference than lm rating leads to think.

Agreed, and we need to also consider the UV emitted from each bulb.

 

[etinarcadiaego]

An optical watt (emitted light) of CMH only produces 285lm, vs 385lm of a typical HPS. So, its not the HPS emits more light, but more lm: the light they emits produces an higher brightness sensation for human, but not for plants.

1000lm of CMH (4200K) holds near 16 micromols of photons. While 1000lm of HPS holds 11.5-12uE.

So 31000lm of CMH=496uE

49000lm of HPS=563 to 588uE.

So, the HPS emits more photons, but there is way less difference than lm rating leads to think.

right we agreed that HPs emits more lumens, which is a standard created by people to measure as you mention, perceived light. Check this out, a great read about lumens and what they do and don't measure.

I followed the rest of your post, but it didn't really quantify the amount of photosynthetic reactive energy emitted by a particular bulb, though I don't think that's what you had in mind.

 

[knna]

right we agreed that HPs emits more lumens, which is a standard created by people to measure as you mention, perceived light. Check this out, a great read about lumens and what they do and don't measure.

I followed the rest of your post, but it didn't really quantify the amount of photosynthetic reactive energy emitted by a particular bulb, though I don't think that's what you had in mind.

Great link, its difficult to find pages that explain those concepts well.

Yeap, I did not wanted to enter into the conflictive topic of induced photosynthesis by different wavebands and light spectrums, but just state the actual light emission of both lamps in the unit meangliful for plants, micromoles of photons per second (uE).

But the photosynthetic response of plants is basically flat to all absorbed photons into the PAR range (400-700nm), irrespective of its wavelenght. There are differences, but they are small, and mainly produced by the different absorbance of each wavelenght, as one absorbed photon usually has the same potential of induce photosynthesis whatever wavelenght it is.

Its impossible to state how much photosynthesis induces photons of different wavelenght in the practice, due the adaptative nature of plants. But its possible to state some orientative figures, based on the data of botanist experiments, for unsaturated photosynthesis.

Using the Inada curve, which sum the effect of absorbance and quantum yield, the 4200K CMH result on a efficacy of 75%, and a typical HPS spectrum (phillips Son T), an efficacy of 78%.

Using the McCree curve and the cannabis absorbance of photons (thus, a more accurate way), it result on a efficacy of 74% (CMH) and 80% (HPS) respectively, when applied to the baseline of photon emission. But in the practice, difference is smaller. And when using high light levels, the efficacy of the bluiser CMH is way less affected (in the negative way) than its than of HPS. And the effect of higher UV (below 400nm), with reduced but positive photosynthesis induction narrow the edifference even more, as noted by hoosierdaddy

So resuming, there is little difference in efficacy of photons inducing photosynthesis for both type of lamps, and the photon output of each is a very good sign of their potential. And always take in mind that there are other things apart of photosynthesis, that are impossible to quantify (leaves to calixes ratio, production of resin, effects over cannabinoid profile...)

 

[etinarcadiaego]

Thanks for the info man! Very interesting!

But the photosynthetic response of plants is basically flat to all absorbed photons into the PAR range (400-700nm), irrespective of its wavelenght. There are differences, but they are small, and mainly produced by the different absorbance of each wavelenght, as one absorbed photon usually has the same potential of induce photosynthesis whatever wavelenght it is.

Hmm, just wondering, as I've read information to the contrary before on other forums (not technical data), where did you find this information? Though I've suspected it before, I have never found anything actually stating that photons of light, regardless of wavelength, stimulate the same photosynthetic response. I've read some things recently that seem to say this, but none seem to offer it as a final conclusion or state in clear not-uncertain terms, if you will. For instance, check this read out. I really liked it's description of the various processes and how each leads to another more in-depth reaction, though this goes FAR more in-depth than needed.

This here seems to support what you said, as it states that chlorophyll a & b, which as mentioned in the first link are there to aid one another so as to absorb as much light as possible, both begin a process which ends the same way, thus each has the same result . . .

Here is a brief quote "The different sidegroups in the 2 chlorophylls 'tune' the absorption spectrum to slightly different wavelengths, so that light that is not significantly absorbed by chlorophyll a, at, say, 460nm, will instead be captured by chlorophyll b, which absorbs strongly at that wavelength. Thus these two kinds of chlorophyll complement each other in absorbing sunlight. Plants can obtain all their energy requirements from the blue and red parts of the spectrum, however, there is still a large spectral region, between 500-600nm, where very little light is absorbed. This light is in the green region of the spectrum, and since it is reflected, this is the reason plants appear green. Chlorophyll absorbs so strongly that it can mask other less intense colours. Some of these more delicate colours (from molecules such as carotene and quercetin) are revealed when the chlorophyll molecule decays in the Autumn, and the woodlands turn red, orange, and golden brown."

This seems to state pretty clearly that light is absorbed by one or the other chlorophyll, depending the wavelenth as shown here:

And that the light is absorbed and begins a chain reaction, REGARDLESS of the wavelength it was absorbed at or by which chlorophyll. That fascinates me for one reason, which would be that it implies that I could grow a plant under a single light source emitting light at one specific wavelength, provided either chlorophyll a or b could absorb it (wouldn't matter which), and that I'd get a healthy plant as a result.

I don't know that to be untrue, but it certainly seems contrary to the beliefs of many who claim that MH which emits light at a shorter wavelength, lead to shorter, squatter plants with tighter inter-node spacing versus HPS with light at longer wavelengths which can lead to stretch. Unless it would be a result of the bluer MH light have greater intensity because of its shorter wavelength and thus greater energy (inverse relationship between wavelength and energy, right?) . . .

In spite of this evidence, I've read elsewhere on this site (wish I could find the thread) that shows an image with depicting various wavelengths of light and what each will lead to in terms of plant-growth response. Is this wrong then? I'm not sure where it came from, only that i've seen it and what it claimed . . .

There are differences, but they are small, and mainly produced by the different absorbance of each wavelenght

What are the differences? Based on the above chart, does this mean that a & b are in fact different in terms of beginning the photosynthetic process?

Using the Inada curve, which sum the effect of absorbance and quantum yield, the 4200K CMH result on a efficacy of 75%, and a typical HPS spectrum (phillips Son T), an efficacy of 78%.

Using the McCree curve and the cannabis absorbance of photons (thus, a more accurate way), it result on a efficacy of 74% (CMH) and 80% (HPS) respectively, when applied to the baseline of photon emission. But in the practice, difference is smaller. And when using high light levels, the efficacy of the bluiser CMH is way less affected (in the negative way) than its than of HPS. And the effect of higher UV (below 400nm), with reduced but positive photosynthesis induction narrow the edifference even more, as noted by hoosierdaddy

So what you're saying here is that the data actually favors HPS in terms of plant-usable-light emitted per watt of electricity used, though you go on to mention that the difference in real-life performance may be substantially less noticeable. What would cause that to be the case?

And when using high light levels, the efficacy of the bluiser CMH is way less affected (in the negative way) than its than of HPS.

I'm not sure I follow. Are you saying that when using more light (multiple sources, stronger point sources???) the CMH actually performs a little better?

You also mention that the UV light emitted by the CMH adds to making the difference less noticeable. I've read that the amount of UV emitted by a 400 watt CMH is nominal, is that incorrect?

Also, what you would attribute the difference in bud structure to plants (clones) grown under HPS vs CMH? I ask this in part because if the data does suggest that the photosnythetic response is not wavelength dependent, what would cause the structural difference, or is there none?

 

[knna]

In order to no highjack the CMH thread, Ive opened a thread about this topic, that I think deserves it:

Effects of light quality (spectrum) on plants

 

[DonkDBZ]

Could I hang my 400w Retro White Horizontal bulb Vertically?

 

[love?]

Anyone know an online store which operates within the European Union that sells 250W CMH bulbs (220V)?

 

[coxswain]

Anyone know an online store which operates within the European Union that sells 250W CMH bulbs (220V)?

No! At least not the Philips one. We've been there. Oh and bulb needs a ballast. Voltages relate to ballasts.

 

[love?]

So you're saying I could order a bulb meant for the States just as well?

 

[coxswain]

So you're saying I could order a bulb meant for the States just as well?

The bulb itself doesn't care what voltages are in the main power grid. It gets fed by an aditional unit (ballast + switch/starter).

From what I've learned so far you would be perfectly fine with a magnetic ballast + starter. It's more reliable and cheaper then electronic/digitall ballasts. For example Vossloh Schwabe 250@ ballast and 250 Philips CMH light that you can purchase from advancedtechlighting.com.

 

[love?]

Right, that's good to know. Thanks for the info.

I'm running a 250W HPS setup with a magnetic ballast so all I would need is the bulb, will have to consider whether or not the experiment is worth the customs paranoia involved with ordering stuff from outside the EU tho.