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DungenessDank said:
What really is important is what is the plant itself using to produce its energy. I think spectrum and coverage matters much more for marijuana than the overall light a bulb produces. How much of that light is going to waste vs how much light is the plant using.

Not to change the debate, but this MJ cultivation

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Harry_Ba11sach said:
even amongst the scientific community theres a grand debate over photosynthesis and artificial lighting. In one camp they say that plants utilize the full spectrum from high frequency ultraviolet all the way down to far infra-red and that growing without the full broad-spectrum will yield deficient results. The other camp looks at graphs of peak photosynthetic efficiency and claims that since chlorophyll, xanthophyll and carotenoids all have their specific peak wavelength that putting energy into producing light at any other wavelength is just a waste of energy. I wish I had an answer for you, but professional biologists and botanists haven't even agreed on an answer yet.

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Carotenoids, xanthophyll and chlorophyll are merely the pigments within the chloroplasts (photosynthetic organelles) that absorb the light. scientists have figured out down to the single nanometer exactly which wavelengths are absorbed best by each of these pigments. this is the "PAR" that kine referred to, PAR standing for Photosynthetically active radiation. 
The problem here is that although there are certain peaks where the pigments absorb best, they still do work at other wavelengths. just because they're best at one color doesn't mean that all the other colors are useless see this graph for an example.


Lumens are useless in this debate anyway since they in no way have any bearing on the activation of photosynthetic organelles. the only necessary measurement is the intensity of the light source.

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Too make it more difficult, is it possible that marijuana has special photosynthetic organelles that other plants do NOT have because they are used by Cannabis spp. in the production of the psychoactive resin in the female flowers. I mean, the fact that a plant can make crystalline solids on its leaf surface, that when vaporized to the point of combustion, there are psychoactive in mammals (reptiles?). I mean, what other plant can such an unusual task.

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You are absolutely correct, very good inference   From the little research that's been done it's been speculated that UV-B is the specific wavelength for catalyzing production of THC but unfortunately until MJ gets classified in a schedule that allows medical research nothing concrete can be published

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TrueHerbCrystal said:

Anyway, that's another debate: Why does female marijuana flowers produce crystalline Resin on their surface? What function does it have for the plant itself?

Harry, You are the smartest guy I Currently know.
~ TrueHerbCrystaL ~

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TrueHerbCrystal said:
"Pest deterrent" huh...interesting...natural nature is amazing!

That explains why its psychoactive: its likely a poison to non-mammal animals such as worms or chiggers (can alligators get stoned? Komoto Dragons? Anyone?).

"Sunscreen" too....what is it protecting? The sites here the pollen is picked up?

~ TrueHe4bCrystaL ~

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So can you give me an example of unnatural nature? 

But yes; alligators and komoto's can get stoned (we got my friends bearded dragon stoned often lol)... why couldnt they?  It'd be the same if they ate mushies... but somehow i doubt alligators and komoto's are weeds natural predators that the THC helps protect against...

And as sunscreen its to protect the plant itself entirely.  This is why you get trichs on stems as well.  UV rays are harmful in everyway.  While humans; and plants both need small ammounts of UV; the sun puts out more then enough! (Humans only need like 15 min/day)  So without the trichs; all those UV rays would harm the plant.  So the trichs absorb some of that UV ray.  Then the other trichs act as bug trap (thats why its all sticky icky icky)...

And yes, lux and lumens are retarded confusing.

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DungenessDank said:
So is the current accepted theory that the trichome absorbs the UV radiation from the sun? I remember hearing something about this and the creation of THC-V (?) but I didn't know if this was hearsay or a widely accepted thing.

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TrueHerbCrystal said:

Too make it more difficult, is it possible that marijuana has special photosynthetic organelles that other plants do NOT have because they are used by Cannabis spp. in the production of the psychoactive resin in the female flowers. I mean, the fact that a plant can make crystalline solids on its leaf surface, that when vaporized to the point of combustion, there are psychoactive in mammals (reptiles?). I mean, what other plant can such an unusual task.

I mean, a "flower" is used by plants for pollination by either insects or wind, and this plant produces a sticky resin in that same area as the psychoactive flower. Whats that resin flower for anyway? Is it to capture the pollen flying in by the wind? Makes sense, but that its psychoactive, whaaaa....

Anyway, that's another debate: Why does female marijuana flowers produce crystalline Resin on their surface? What function does it have for the plant itself?

Harry, You are the smartest guy I Currently know.
~ TrueHerbCrystaL ~

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201 "beams" of cobalt-60 gamma radiation are focused on the region to be treated. The beams go through the skull in different spots, with each beam too weak to hurt normal tissue. However, when they all come together in the area to be treated, they are then strong enough to destroy the tumor. It is a type of single-fraction radiosurgery.

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chucklehead said:

ON TOPIC

Regardless of the distance of the lights or their position in space relative to the surface what matters is the light that reaches that fixed surface.  So given that the additional lights can reach that same surface the lux (the light that does reach the surface) will add up in a linear way.  I think the hang up here is people are mixing up lumens and lux and thinking light output = light received by the surface.  The example that comes to my mind is me standing outside on a clear night.  I look up into the sky.  I can see lots of stars at the same time when I look at a fixed point in space.  Which means beams of light from those stars that are light years away from me are hitting my retinas at the same time.  Obviously all of the light being output by those stars isn't reaching me.  Otherwise chucklehead would be vaporized.  So with each additional star more light from far away points in space is getting to the surface of my retinas (a relatively small fixed surface area very far away from the origin of the light). 

Another example I think about is the gamma knife.  Since I lack the skill to describe it well myself I'll provide this link and a quote

http://survivethejourney.blogspot.com/2009/03/gamma-knife-radiosurgery.html

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201 "beams" of cobalt-60 gamma radiation are focused on the region to be treated. The beams go through the skull in different spots, with each beam too weak to hurt normal tissue. However, when they all come together in the area to be treated, they are then strong enough to destroy the tumor. It is a type of single-fraction radiosurgery.

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Also who is arguing CFLs are as good as HIDs?  This argument is about adding more lights (no matter the type) and what effect that will have on light received by a fixed surface area near by.

Bottom line for me is this.  Is the addition of more lights better for my plant?  Looks to me like the answer is yes.  More light gets to a given surface area and more surface areas are receiving light.

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Irradiance
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Irradiance, radiant emittance, and radiant exitance are radiometry terms for the power per unit area of electromagnetic radiation at a surface. "Irradiance" is used when the electromagnetic radiation is incident on the surface. "Radiant exitance" or "radiant emittance" is used when the radiation is emerging from the surface. The SI units for all of these quantities are watts per square meter (W/m2), while the cgs units are ergs per square centimeter per second (erg·cm−2·s−1, often used in astronomy). These quantities are sometimes called intensity, but this usage leads to confusion with radiant intensity, which has different units.

All of these quantities characterize the total amount of radiation present, at all frequencies. It is also common to consider each frequency in the spectrum separately. When this is done for radiation incident on a surface, it is called spectral irradiance, and has SI units W/m3, or commonly W·m−2·nm−1.

If a point source radiates light uniformly in all directions and there is no absorption, then the irradiance drops off in proportion to the distance from the object squared, since the total power is constant and it is spread over an area that increases with the square of the distance from the source.



[edit] Technical details
The irradiance of a light wave is given in terms of its electric field by

,
where E is the complex amplitude of the wave's electric field, n is the refractive index of the medium, c is the speed of light in vacuum, and ε0 is the vacuum permittivity.

Irradiance is also the time average of the component of the Poynting vector perpendicular to the surface.

[edit] Solar energy
Irradiance due to solar radiation is also called insolation. The global irradiance on a horizontal surface on Earth consists of the direct irradiance Edir and diffuse irradiance Edif. On a tilted plane, there is another irradiance component: Eref, which is the component that is reflected from the ground. The average ground reflection is about 20% of the global irradiance. Hence, the irradiance Etilt on a tilted plane consists of three components: Etilt = Edir + Edif + Eref.[1]

The integral of solar irradiance over a time period is solar irradiation. Irradiation is measured in J/m2 and is represented by the symbol H.[1]

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Light is measured with two main alternative sets of units: radiometry consists of measurements of light power at all wavelengths, while photometry measures light with wavelength weighted with respect to a standardized model of human brightness perception. Photometry is useful, for example, to quantify illumination intended for human use. The SI units for both systems are summarized in the following tables.

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The photometry units are different from most systems of physical units in that they take into account how the human eye responds to light. The cone cells in the human eye are of three types which respond differently across the visible spectrum, and the cumulative response peaks at a wavelength of around 555 nm. Therefore, two sources of light which produce the same intensity (W/m2) of visible light do not necessarily appear equally bright. The photometry units are designed to take this into account, and therefore are a better representation of how "bright" a light appears to be than raw intensity. They relate to raw power by a quantity called luminous efficacy, and are used for purposes like determining how to best achieve sufficient illumination for various tasks in indoor and outdoor settings. The illumination measured by a photocell sensor does not necessarily correspond to what is perceived by the human eye, and without filters which may be costly, photocells and CCDs tend to respond to some infrared, ultraviolet or both.

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