PAR measurement thread

[PhotonFUD]

Whatever useful information you feel you have to share is unlikely to be heard... cos you come across as a real arrogant douchebag. You might want to work on that if you want people to listen to you

Well if that's how you feel then by all means don't contribute. Science cares about the data, not feelings. In academia, it is generally positive when something new is discovered or an idea improved upon. Answering the unknown that is what drives research.

I don't see how anything I have posted would be offensive to anyone. That is of course unless they aren't capable of understanding, are ignorant or have some personal benefit at stake. There is at least one vendor (or former vendor, status unsure) that even exhibited all three!

All I have done is pointed to legitimate science and research information. Sure it conflicts with what some here believe but science really doesn't care much about things like beliefs and faith; it leaves those to religion. And as I have said before, if it works for you then great.

 

[MrTwist1]

Well if that's how you feel then by all means don't contribute. Science cares about the data, not feelings. In academia, it is generally positive when something new is discovered or an idea improved upon. Answering the unknown that is what drives research.

I don't see how anything I have posted would be offensive to anyone. That is of course unless they aren't capable of understanding, are ignorant or have some personal benefit at stake. There is at least one vendor (or former vendor, status unsure) that even exhibited all three!

All I have done is pointed to legitimate science and research information. Sure it conflicts with what some here believe but science really doesn't care much about things like beliefs and faith; it leaves those to religion. And as I have said before, if it works for you then great.

I'm not talking about science, I'm talking about the condescending tone in your posts.

 

[HydoDan]

I'm not talking about science, I'm talking about the condescending tone in your posts.

Yeah bud you argued your way onto my ignore list. You can't tell growers how to grow if you don't know how..
Now that is science!!

 

[a mongo frog]

Yeah bud you argued your way onto my ignore list. You can't tell growers how to grow if you don't know how..
Now that is science!!

Whats an ignore list?

 

[JorgeGonzales]

Check under your username top of page..

I think he meant: "Ignore lists are for pussies!"

 

[PhotonFUD]

I'm not talking about science, I'm talking about the condescending tone in your posts.

Well if you think it is condescending that means you are injecting your personal feelings into the discussion. Condescension is subjective; what you believe is condescending doesn't mean it is to others.

The sharing of information would only be considered condescending to the ignorant.

Now enough about hurt 'feelings' and get back to the topic.

 

[JorgeGonzales]

I don't see how anything I have posted would be offensive to anyone. That is of course unless they aren't capable of understanding, are ignorant or have some personal benefit at stake.

Buddy, sometimes condescension is objective. Wow.

 

[Rahz]

I'm not sure what we're arguing about. 400 PPFD is optimal if the goal is to be as photo-synthetically efficient as possible. With unlimited space it might make sense but I'm not sure anyone is going to shoot for 400. On the efficiency side with the space 600 PPFD makes notable yield gains with minimal efficiency loss. 800+ is for those looking to maximize their yield per foot. Most people will be aiming for the 800+ range.

 

[a mongo frog]

Whats a twat exactly?

 

[Abiqua]

Well if you think it is condescending that means you are injecting your personal feelings into the discussion. Condescension is subjective; what you believe is condescending doesn't mean it is to others.

The sharing of information would only be considered condescending to the ignorant.

Now enough about hurt 'feelings' and get back to the topic.

You have replied more times on hurt feelings then on the actual nuances of your theory. Which level do you think you ascribe to and which do you think is reality....down around the bottom is what I feel is more or less correct. Glib quotes notwithstanding....

 

[Abiqua]

Whats a twat exactly?

british for teabagging antiquing

 

[PhotonFUD]

I'm not sure what we're arguing about. 400 PPFD is optimal if the goal is to be as photo-synthetically efficient as possible. With unlimited space it might make sense but I'm not sure anyone is going to shoot for 400. On the efficiency side with the space 600 PPFD makes notable yield gains with minimal efficiency loss. 800+ is for those looking to maximize their yield per foot. Most people will be aiming for the 800+ range.

Finally something intelligent. With the amount of spam from the ignorant cult following, I was beginning to wonder if this forum was going to be beneficial in ways other than providing entertainment. It makes more sense now that governments want to maintain control of production if it is these kind of people who are producing medicine for others.

You need to drop space as we are concerned with the area being serviced by the light source. In any given space we can use a small area; we can also divide the space horizontally and vertically to increase area. What I have said and still maintain, is that the optimal intensity of light would be somewhere in the ~410-600 umoles range for the entire plant, not just the canopy. Bubble wrap your plant in warm, gentle light.

I just put it out there to see if anyone else would pick up on it. A couple have and a few other people have contributed positively to the conversation. There are quite a number of journals showing successful side and vertical growing methods in use so the results are out there for all to see. But more importantly it is how you figure it out to work best for your environment.

At least now I have a better idea who is intelligent and who is not. It is best to avoid fools; it is even better when they self-identify.

 

[wietefras]

Incorrect. PPF would be photons emitted at source, so going out. In order to fill that 10 liter bucket, it would have to catch all of the light.

It's emitted in a closed room with reflective walls. So yes, it's all in there. Minus wall losses (and reflector losses, but they should have been processed in the PPF already)

Come on man!

You are even wrong about wall losses - with the same light source and all other things being equal, a larger room will have more total wall loss than a small one. That is just simple math.

Again, come on man! It's relatively less of course. People who design grow rooms use correction factors for wall losses and they are smaller for larger rooms. Actually they use software that calculates the PPFD over the whole surface based on the PPF of the lights, walls and distribution of the fixtures.

As to your comments regarding the text published by Cambridge University Press, its speaks volumes about your character and ignorance. Cambridge is the world's second oldest english language university and a world leader in plant research. Stephen Hawking is a professor there. Any normal person would consider it to be an expert source for factual information.

There is nothing wrong with the University or it's books. The problem is that YOU don't understand that chart. It's used to show schoolkids the general principle of light response. Yet you interpret it as the holy grail of light response curves. As if there is only one and the saturation point is at 400umol for all species.

 

[wietefras]

What I have said and still maintain, is that the optimal intensity of light would be somewhere in the ~410-600 umoles range for the entire plant, not just the canopy. Bubble wrap your plant in warm, gentle light.

No, a quick search for ~400umoles shows that you have said:

Target for ~400umoles as uniform as possible.

That is where the ~400 umoles comes from. It is the amount needed to maximize the rate chlorophyll can perform photosynthesis.

an accredited university which happens to show a chart where the photosynthetic rate increase peaks ~400 umoles.

The documentation I have referenced finds that photosynthesis has a saturation point at ~400 umoles which if applied to an entire plant would have the potential to reach optimal photosynthetic efficiency.

DLI is what we should be using. 18-25 mol/d is a good target. (which is 400 to 600umol/s/m2)

It's also in your avatar for Pete's sake.

You even said that adding more COBs to create a PPFD of 600umol/s/m2 would give you the same yield as 400umol/s/m2.

Over and over and over you keep claiming 400umol is the maximum that a plant can usefully process. Sometimes you cop out and admit maybe up to 600umols might work or you add some vague nonsense about "whole plant" needing to be in the same light, but clearly plants can go well over that and even up to 1500umol/s/m2 with increasing yields. There is no saturation point at 400 or 600umol

The Chandra chart was based on tests on leaves. A single leaf having more photosynthesis with more light up to 1500umol/s/mw also. So you cannot hide under your "the light goes through to the other leaves and creates 400umol there". If you had ever grown cannabis plants you'd know this is nonsense BTW

Which brings me to the other claim you make:

1. Find the saturation point of your plant.

If you look at the charts, aiming for the saturation point is daft. Everybody picks a spot on the curve where the efficiency starts to come off the straight angle. That's what professionals aim for. Not the maxium light level that the plant can handle. Which would be 1500umol/s/m2 for Cannabis plants.

In fact people tend to aim for half the light of the saturation point. So based on your holy chart of light response, 200umol should be your aim for maximum efficiency

 

[PhotonFUD]

It's emitted in a closed room with reflective walls. So yes, it's all in there. Minus wall losses (and reflector losses, but they should have been processed in the PPF already)

Come on man!

Again, come on man! It's relatively less of course. People who design grow rooms use correction factors for wall losses and they are smaller for larger rooms. Actually they use software that calculates the PPFD over the whole surface based on the PPF of the lights, walls and distribution of the fixtures.

There is nothing wrong with the University or it's books. The problem is that YOU don't understand that chart. It's used to show schoolkids the general principle of light response. Yet you interpret it as the holy grail of light response curves. As if there is only one and the saturation point is at 400umol for all species.

Ok then, compromise, I shall clarify - all plant and algae species that use chlorophyll to perform photosynthesis.

 

[wietefras]

Ok then, compromise, I shall clarify - all plant and algae species that use chlorophyll to perform photosynthesis.

Still bullshit. Get it through your head that there is not one light response curve for all plants and even for all leaves on a plant.

 

[PhotonFUD]

No, a quick search for ~400umoles shows that you have said:











It's also in your avatar for Pete's sake.

You even said that adding more COBs to create a PPFD of 600umol/s/m2 would give you the same yield as 400umol/s/m2.

Over and over and over you keep claiming 400umol is the maximum that a plant can usefully process. Sometimes you cop out and admit maybe up to 600umols might work or you add some vague nonsense about "whole plant" needing to be in the same light, but clearly plants can go well over that and even up to 1500umol/s/m2 with increasing yields. There is no saturation point at 400 or 600umol

Which brings me to the other claim you make:


If you look at the charts, aiming for the saturation point is daft. Everybody picks a spot on the curve where the efficiency starts to come off the straight angle. That's what professionals aim for. Not the maximum light level that the plant can handle. Which would be 1500umol/s/m2 for Cannabis plants.

It is a range. And more specifically a range over an effective distance (crudely referred to as penetration) at the leaf surface. Unless you want to 'pancake' your plant there is no way you are going to get it completely uniform. Mind you there are some pictures of vertical grows with sun cloaks that are pretty close.

As this has been going on way too long I am just going to jump right to the point. Uniformity is important, far more important than is given attention to. Everyone seems content with smashing their plants from above with as much light as they can and neglecting the other areas of the plant. If you redistribute some of that light power to become more uniform to the plant, you will get much better results using the same amount of power and lights. If running high wattage it will also help with thermal management. And you will like this one, you can adjust the light sources to take advantage of reflectivity.

However most people are stuck on 'as much as possible at all costs' to the canopy and aren't willing to reduce intensity at the canopy to improve side lighting. I just put the photosynthesis rate out there as boundary to show how low you could go. You still need to get that light to the lower leaves that are getting less than 200 umoles so I am not saying to give less overall light.

Another thread is picking up on the efficiency being higher in the ~400 umoles region compared to 800. Just wait, you guys might get there.

Besides, if you could increase production just by placing your lights better, wouldn't you? That is that matters to anyone and it is probably worth your time and effort to look into.

 

[PhotonFUD]

Still bullshit. Get it through your head that there is not one light response curve for all plants and even for all leaves on a plant.

For photosynthesis they do.

You can disagree with that all you want, it still won't change it

 

[wietefras]

How do you think we will fall for your "for photosynthesis" cop out? You literally claim not to hang more than 400umol/s/m2 over our grows. There is no "oh but I'm only talking photosynthesis guys" bullshit there. You have been show over and over that the plants can deal perfectly fine with much higher light intensities like 1500umol/s/m2. Not just the plants, but individual leaves also.

You are simply wrong. No vague goal post moving is going to save you from this. Stop with the trolling already.

That 400umol chart you use is one light response curve. By the looks of it, it's for a shadow leaf. Now look up a light response curve for a sun leaf and you will see that indeed those can go up to 2000umol/s/m2.

Another thread is picking up on the efficiency being higher in the ~400 umoles region compared to 800. Just wait, you guys might get there.

Yeah I posted that chart. Yet you claimed there is zero gain from going from 400 to 800umol. Or sometimes you seem to know you are wrong (a bit) and admit maybe from 400 to 600 there is a tiny gain, but then going to 800 there is no gain

Well the cannabis related charts show you are wrong in both cases

 

[PhotonFUD]

How do you think we will fall for your "for photosynthesis" cop out? You literally claim not to hang more than 400umol/s/m2 over our grows. There is no "oh but I'm only talking photosynthesis guys" bullshit there. You have been show over and over that the plants can deal perfectly fine with much higher light intensities like 1500umol/s/m2.

You are simply wrong. No vague goal post moving is going to save you from this. Stop with the trolling already.

That 400umol chart you use is one light response curve. By the looks of it, it's for a shadow leaf. Now look up a light response curve for a sun leaf and you will see that indeed those can go up to 2000umol/s/m2.

Cop out? Quit making assumptions, that is what stupid people do. I have not changed anything with my position. And you are free to believe in whatever you want to, whether it is right or wrong.

This is somewhat tiring trying to educate you. I thought you had potential but you are just as dumb as the other ignorant cult followers. The rest of them are falling backwards over themselves posting distracting information about their 'feelings' in a science discussion. Quite comical actually.

Anyhow my advice to you is to go get some real education. If you still don't understand then maybe horticulture isn't for you. And there isn't anything wrong with that, some people aren't good with plants. Or numbers. And sometimes even with irrefutable facts.