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

[PurpleBuz]

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

I am being sincere and even the link you gave backs up what I am saying, Use your brain and read more and surely something more than a biology 101 summary. try this on for size. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3899860/

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

that is EXACTLY what your statement says:

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

and that's exactly what I'm bitching about.

 

[wietefras]

that is EXACTLY what your statement says:

No it isn't I never said anything about energy lost. The blue absorbing pigment absorbs 4 photons. Regardless of energy. So the plant doesn't care about energy, but about photons.

and that's exactly what I'm bitching about.

So, annoying semantics it is. Great And ignore it is too.

 

[PurpleBuz]

No it isn't I never said anything about energy lost. The blue absorbing pigment absorbs 4 photons. Regardless of energy. So the plant doesn't care about energy, but about photons.

So, annoying semantics it is. Great

sorry that's not semantics hi energy photons are less efficient because energy is lost as the energy transfers to the chlorophyll molecules. BUT NOT ALL OF IT IS LOST WHICH IS WHAT YOU SAID. The conversion rate varies greatly depending on the light absorbing pigments involved.

another idiot that just can't admit that they are wrong .... boo hoo

 

[Olive Drab Green]

sorry that's not semantics hi energy photons are less efficient because energy is lost as the energy transfers to the chlorophyll molecules. BUT NOT ALL OF IT IS LOST WHICH IS WHAT YOU SAID. The conversion rate varies greatly depending on the light absorbing pigments involved.

another idiot that just can't admit that they are wrong .... boo hoo

I wasn’t technically wrong, you were just applying Nondualistic principles to an irrelevant situation. That said, I wasn’t trying to be rude.

 

[PurpleBuz]

I wasn’t technically wrong, you were just applying Nondualistic principles to an irrelevant situation. That said, I wasn’t trying to be rude.

I wasn't responding to you I understand what you were saying.

 

[Olive Drab Green]

I wasn't responding to you I understand what you were saying.

Gotcha.

 

[ANC]

quantum physics is a human model

A quantum is one moll of photons also called an eisntein unit.
What is important is how many μmol m−2 s−1 hits the canopy and how full the canopy is. so that it can effectively receive the light.

 

[wietefras]

A quantum is one moll of photons also called an eisntein unit.
What is important is how many μmol m−2 s−1 hits the canopy and how full the canopy is. so that it can effectively receive the light.

Exactly. We can argue semantics about what happens inside the plant with different energy levels per photon of different wavelenghts, but that's irrelevant to the discussion about using PAR W instead of PPF.

The point is that when you have say 100 PAR W of light you get a difference of 47% in the number of photons comparing blue and red leds. That's not a small inaccuracy and especially not something that should compel to stop using the industry standard metrics.

 

[Olive Drab Green]

Exactly. We can argue semantics about what happens inside the plant with different energy levels per photon of different wavelenghts, but that's irrelevant to the discussion about using PAR W instead of PPF.

The point is that when you have say 100 PAR W of light you get a difference of 47% in the number of photons comparing blue and red leds. That's not a small inaccuracy and especially not something that should compel to stop using the industry standard metrics.

PAR W is input energy, not output. Technically, it’s an efficiency thing, regarding how much wattage is used to produce PPF and PPFD. So, it’s irrelevant to plant-side of things.

 

[wietefras]

PAR W is input energy, not output. Technically, it’s an efficiency thing. So, it’s irrelevant to plant-side of things.

No, that's the radiated watts output in PAR spectrum.

Although churchhaze could technically also be talking about all radiated energy, but that would make even less sense and I'm not like PurplePus, purposefully looking for incorrect interpretations of what people write to start a semantic whine fest about it.

 

[churchhaze]

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.

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


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

Well good luck trying to maximize for PPF at the expense of a compromised SPD rather than an increase in power. I'm sorry but it's not a fallacy. Without changing the spectrum (toward red), you're breaking the first law (beating the system). There's only one way to increase PPF without changing SPD, and that's increasing power.

3) Plants deal with photons, not with radiated energy

You do realize what the whole point of photosynthesis is, right? Plants don't just store the photons in buckets. Those photons are radiated energy.

 

[churchhaze]

The point is that when you have say 100 PAR W of light you get a difference of 47% in the number of photons comparing blue and red leds. That's not a small inaccuracy and especially not something that should compel to stop using the industry standard metrics.

What makes something inaccurate is error.... Dividing by a constant factor will never be a source of error. Instruments could be calibrated poorly, or humans could make mistakes. Those are sources of error. Even luminous flux has the same accuracy as PPF. The only reason not to use lumens is it's not intuitive for our purposes.

 

[wietefras]

What makes something inaccurate is error.... Dividing by a constant factor will never be a source of error. Instruments could be calibrated poorly, or humans could make mistakes. Those are sources of error. Even luminous flux has the same accuracy as PPF. The only reason not to use lumens is it's not intuitive for our purposes.

Yes it is an error. Both produce 100 PAR W, but one produces 47% more photons.

 

[wietefras]

3) Plants deal with photons, not with radiated energy

You do realize what the whole point of photosynthesis is, right? Plants don't just store the photons in buckets. Those photons are radiated energy.

Yes that is exactly what they do. The systems needs a couple of photon sized pumps to trigger a reaction. It's based on distinct photon counts.

 

[churchhaze]

@wietefras , your argument implies that blue photons have the same effect as red photons, just with more wasted energy per photon.

Your theory that only quantity matters suggests that blue photons are wasteful, but the reality is that plants need 10-20% for optimal growth. You can't just replace all higher energy photons with photons that have just enough energy to produce photosynthesis while still expecting healthy growth. Your theory also implies that green, yellow, and orange photons are wasteful for having more energy than needed.

Sorry, but the only viable way to up PPF is to up power.

 

[Stink Bug]

@wietefras , your argument implies that blue photons have the same effect as red photons, just with more wasted energy per photon.

Your theory that only quantity matters suggests that blue photons are wasteful, but the reality is that plants needs 10-20% to stay healthy. You can't just replace all higher energy photons with photons that have just enough energy to produce photosynthesis while still expecting healthy growth.

Sorry, but the only viable way to up PPF is to up power.

Yep. There are different forms of chlorophyll and pigments in plants that react to different wavelengths of light. Even light in the green band has been shown to be used by plants.

 

[wietefras]

@wietefras , your argument implies that blue photons have the same effect as red photons, just with more wasted energy per photon.

Yes and no. I'm not saying the energy is wasted. I'm saying there are less blue photons per PAR watt and the plants systems react on photons. So yes it matters that you get the photon counts correct. PAR watt or radiant watt is not an accurate measure of the number of photons. When comparing 450nm and 660nm photons, you are off by 47% when using par W.

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. PAR W is easily 47% off.

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

 

[churchhaze]

Yes and no. I'm not saying the energy is wasted. I'm saying there are less blue photons per PAR watt and the plants systems react on photons. So yes it matters that you get the photon counts correct. PAR watt or radiant watt is not an accurate measure of the number of photons. When comparing 450nm and 660nm photons, you are off by 47% when using par W.

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. PAR W is easily 47% off.

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

There is no such unit as PAR W. Watts are watts. There isn't a different unit for different types of energy. That would be like calling a jeeps speed jeep miles/hour while a honda has honda miles/hour.

Once again, efficiency more intuitively tells you how well your system is performing relative to the theoretical maximum. Energy is how you measure what comes out of your wall and what you pay for. umol/J on the other hand does not intuitively make this clear.

It's also more intuitive to measure the fuel in your car based on volume of gasoline rather than the quantity of C-H bonds.

 

[wietefras]

Once again, efficiency more intuitively tells you how well your system is performing relative to the theoretical maximum. Energy is how you measure what comes out of your wall and what you pay for. umol/J on the other hand does not intuitively make this clear.

You might feel it's more "intuitive", but it's much less incorrect and no one else uses it. You might as well use lumen/lux instead.

There is NO BENEFIT for using efficiency or power. It takes just as much work to divide lumen by a lumen to PART conversion factor (which is LER/QER) as it does dividing lumen by LER. If you need to calculate it at all since often the PPF/PPFD is already known. So it's in fact LESS work to get the PPF/PPFD.

Why on earth would you use an inferior metric when everybody else provides you with the more correct PPF/PPFD numbers or if you need to calculate it you might as well get the right one right away? It just makes no sense. If anything it's much more "intuitive" to compare your figures with actually comparable figures everybody else uses.

It's also more intuitive to measure the fuel in your car based on volume of gasoline rather than the quantity of C-H bonds.

Funny how that example applies much more to your suggestion. Everybody gas station and car manufacturer etc etc measures gasoline in liters. It's the industry standard. Yet you insist on using some other metric which you need to calculate yourself and which is easily 47% off for what you really get out of that fuel. Potentially even 75% off if you take it to extremes. Even comparing white COBs you can be off by 5%.

So you make up a non-standard unit which gives highly inaccurate readings and yet you insist this is better. Yes brilliant.

 

[churchhaze]

You might feel it's more "intuitive", but it's much less incorrect and no one else uses it. You might as well use lumen/lux instead.

There is NO BENEFIT for using efficiency or power. It takes just as much work to divide lumen by a lumen to PART conversion factor (which is LER/QER) as it does dividing lumen by LER. If you need to calculate it at all since often the PPF/PPFD is already known. So it's in fact LESS work to get the PPF/PPFD.

Why on earth would you use an inferior metric when everybody else provides you with the more correct PPF/PPFD numbers or if you need to calculate it you might as well get the right one right away? It just makes no sense. If anything it's much more "intuitive" to compare your figures with actually comparable figures everybody else uses.

Funny how that example applies much more to your suggestion. Everybody gas station and car manufacturer etc etc measures gasoline in liters. It's the industry standard. Yet you insist on using some other metric which you need to calculate yourself and which is easily 47% off for what you really get out of that fuel. Potentially even 75% off if you take it to extremes. Even comparing white COBs you can be off by 5%.

So you make up a non-standard unit which gives highly inaccurate readings and yet you insist this is better. Yes brilliant.

Yes, it is more intuitive for the purposes I keep listing. You keep forgetting to list the pros when you weigh the advantages. As a consumer, I want to know how much light energy I will need, how much electrical energy that will take, how much heat energy I will have to deal with, and how much that will cost. Power and efficiency quickly tells me this.

Also, please learn what accuracy means. It would clear up a lot for you. (with more than just lamps probably)

As for cars, some of them are pure electric and are charged in kWh, a unit of energy. The only reason non-electric cars use volume is because liquid comes out of the pump. If gas was a solid, it would be sold by weight in the us and by mass everywhere else. While 30miles/gallon might give the driver a good idea of what to expect from a gallon of gas, it does not tell him/her what he could be getting with an ideal engine.