Did someone post on a thread that 315 Watt CMH cut a week out of veg?

[wietefras]

I already answered this. You might also be 40% off. Quantity within PAR range is clearly not all that matters or it would imply a pure 699nm SPD is ideal. There's nothing inherently more useful about using PPF over power other than the fact that plants don't want more than 20% blue.

Well as you already understood, it can be 40% more accurate to use PPF rather than efficiency. If anything efficiency figures are useless. There is no benefit to using them instead of PPF/W and they are a lot less accurate. Just use PPF/W.

 

[churchhaze]

Keep repeating the misconception that PPF is somehow more accurate than power despite them being functions of each other. Just fill your grow with red leds to tweek PPF/W ...and... You've beat the system. (Typical stoner logic)

One last time, PPF only seems more important because of how little blue you need. If plants needed 80% blue, people would instead mistakenly believe that power is more accurate than PPF.

People insist on using PPF because it makes them seem cooler or more educated, but it provides no advantage over power and efficiency.

 

[churchhaze]

Things that will reduce accuracy:
Instrumentation error: Yes, this will reduce accuracy
Human error: Yes, this will reduce accuracy.
Multiplying by a constant: No, this will not affect accuracy in any way.

 

[wietefras]

Keep repeating the misconception that PPF is somehow more accurate than power despite them being functions of each other.

It's not a misconception, it's a fact. Them being a function of each other is a gross oversimplification. It's a summation of 300 functions each with their own constant. It's NOT a single constant as you try to pretend.

Just fill your grow with red leds to tweek PPF/W ...and... You've beat the system. (Typical stoner logic)

Oh wait, it gets worse. Reductio ad absurdum really is your thing huh?

People insist on using PPF because it makes them seem cooler or more educated, but it provides no advantage over power and efficiency.

Advantages of umol/s/W:
1) All horticultural lights and components report umol/s/W figures. Easy to obtain figures without the need for digitizing SPDs and calculating LERs
2) In horticulture, light intensity is measured with quantum sensors reporting photon counts.
3) Plants deal with photons, not with radiated energy
4) PPF works correctly both for blue leds and for red leds. If you want to use a 8:2 ratio of R:B you are getting nowhere with PAR W figures. You cannot simply use 80 PAR W red and 20 PAR W blue. For each wavelength used you would need to calculate the appropriate correction factor to photons. When you have an x umol/s/W blue and y umol/s/W red led, then you can simply compare the two on photon counts and quickly calculate the watts needed for each from the umol/J figures readily available.

Advantages of PAR W / efficiency:
1) churchhaze thinks this makes him look cooler or more educated

 

[PurpleBuz]

3) Plants deal with photons, not with radiated energy

excuse me ? that's utter nonsense plants deal with light.

"Photons" or "Energy" or "Waves" are human models to deal with something that has properties of each

 

[Olive Drab Green]

You guys understand that PPF and PPFD are somewhat different, right? Like, PPFD would probably be a more accurate measure than PPF.

 

[Olive Drab Green]

excuse me ? that's utter nonsense plants deal with light.

"Photons" or "Energy" or "Waves" are human models to deal with something that has properties of each

Photons are not human models. They are the light energy units studied in Quantum Physics.

“A photon is a type of elementary particle, the quantum of the electromagnetic field including electromagnetic radiation such as light, and the force carrier for the electromagnetic force (even when staticvia virtual particles). The photon has zero rest mass and always moves at the speed of light within a vacuum.”

 

[PurpleBuz]

Photons are not human models. They are the light energy units studied in Quantum Physics.

quantum physics is a human model

 

[Olive Drab Green]

quantum physics is a human model

No, it’s a physical, observable science. One photon is physically observable and has a physical effect. You need to be more properly educated.

 

[Olive Drab Green]

Photons within the PAR (Photosynthetically Active Radiation) spectrum are the weighted particles of light the plant actually uses for photosynthesis. Photons are also how solar panels work

 

[PurpleBuz]

you are totally missing my point. step back from the trees and see the forest.

 

[Olive Drab Green]

you are totally missing my point. step back from the trees and see the forest.

Alright, I can see what you mean, and as an Advaitin, I agree with you, but in this situation where we’re discussing the science behind optimal plant growth indoors, where there is no forest or sun, we need to investigate the human concept.

 

[Olive Drab Green]

you are totally missing my point. step back from the trees and see the forest.

 

[wietefras]

excuse me ? that's utter nonsense plants deal with light.

"Photons" or "Energy" or "Waves" are human models to deal with something that has properties of each

Plants deal with light in the form of photons. For a plant it doesn't matter that one photon carries 47% more energy than another. So that's why horticulture focuses on photons and not energy.

 

[Olive Drab Green]

Plants deal with light in the form of photons. For a plant it doesn't matter that one photon carries 47% more energy than another. So that's why horticulture focuses on photons and not energy.

Certain photons carry more weight, of course, but I agree. And using a full daylight spectrum is much better than using a blurple board. Watts and electrical energy is a form of input. It’s what the light uses, not the plant. The photons are the output energy.

The reason a 200-250w COB will perform like a 600w HPS is because HIDs are incandescent, meaning they use heat to create light by design. Everyone should easily recognize that heating an element up consumes quite a bit of electricity. COBs use electroluminescence, whereby a current is passed over a phosphor chip creating light. This is how COBs can put out the power of HIDs with less than half the wattage and minimal heat without breaking the Four Laws of Thermodynamics.

 

[PurpleBuz]

For a plant it doesn't matter that one photon carries 47% more energy than another.

That is not exactly true. That has only been shown to correlate in terms of gross quanta. Nobody has been able to prove that the energy of one photon is actually irrelevant, in fact the opposite. There are holes in that theory because of the array of different pigments which feed photosynthesis.

 

[Olive Drab Green]

That is not exactly true. That has only been shown to correlate in terms of gross quanta. Nobody has been able to prove that the energy of one photon is actually irrelevant, in fact the opposite. There are holes in that theory because of the array of different pigments which feed photosynthesis.

Right, which is what I said. I think he means the amount of input energy used to make one output photon.

 

[wietefras]

That is not exactly true. That has only been shown to correlate in terms of gross quanta. Nobody has been able to prove that the energy of one photon is actually irrelevant, in fact the opposite. There are holes in that theory because of the array of different pigments which feed photosynthesis.

Photosynthesis works on photons. The photosynthesis systems need a certain amount of photons for a certain reaction to trigger.

Saying there are "holes in that theory", is this like saying evolution is just a "theory" and should not be taken too seriously.

McCree RQE? Based on photon counts. Not on energy. Quantum meters? Measure photon count and not energy. Etc etc etc. There is a reason for that.

 

[PurpleBuz]

Photosynthesis works on photons. The photosynthesis systems need a certain amount of photons for a certain reaction to trigger.

Saying there are "holes in that theory", is this like saying evolution is just a "theory" and should not be taken too seriously.

McCree RQE? Based on photon counts. Not on energy. Quantum meters? Measure photon count and not energy. Etc etc etc. There is a reason for that.

the mcree example is an observed measurement because that's how we can measure light. irrelevant.

Your original statement is absolutely false:

For a plant it doesn't matter that one photon carries 47% more energy than another.

This statement is more accurate
Higher energy photons like 420 nm light are not as photosynthetically efficient as 680nm light (absorption peak of chlorophyll a), but the energy difference between 420 nm light and 680 nm light is not all lost to photosynthesis

to understand this try reading up on photosynthesis light harvesting complexes.

 

[wietefras]

Your original statement is absolutely false:

No it is not. Look up how photosynthesis actually works. It works on photon counts.

http://hyperphysics.phy-astr.gsu.edu/hbase/Biology/antpho.html

Of course some pigments will absorb blue photons and others red, but in the end only photon count is important to plants. Hence the use of photon counts throughout the industry.

This statement is more accurate
Higher energy photons like 420 nm light are not as photosynthetically efficient as 680nm light (absorption peak of chlorophyll a), but the energy difference between 420 nm light and 680 nm light is not all lost to photosynthesis

That's completely irrelevant to this discussion and I never said the energy difference was lost either.

McCree's RQE chart working with photon counts IS relevant. If it was energy that mattered then they would have used that. There is also an energy weighted McCree photosynthesis efficiency chart which nobody uses.

So are you just playing some annoying semantics game or are you seriously saying energy and photon count are the same thing?