HPS vs. LED Grow Lights — Which is Better for Growing Weed?

Prawn Connery

Prawn Connery

Well-Known Member
Blue brother said:
But it’s not the electrodes In an hid lamp that are the source it is the arc which is a single source.
Click to expand...
Which part of the arc? And how do you quantify your "single source" theory when in fact the emissions along the arc are not linnear due to the fact the hottest part of the sodium gas is near the electrode – hence why double electrode HPS arcs are more efficient than single.

You also do know that the "arc" is not the source of the light: it is the electrons from the individual sodium atoms that rise and fall to a new state, releasing a photon as they fall that is the source of the light – and your "lumens".

So your "single source" is not the HPS lamp and it is not the arc and it is not even the sodium vapour or plasma – it is the individual charged electrons or ions.

How do you explain your theory now?
 
Prawn Connery

Prawn Connery

Well-Known Member
Blue brother said:
My secondary point was that seeing as the single source will have a hotspot in the Center then more light will pass THROUGH (not around) the leaf under this hot spot than it would if there were multiple sources delivering the same number of photons more evenly across the canopy
Click to expand...
Firstly, it depends on the translucence of the individual leaf. Even if the leaves are somewhat translucent, your light might only be able to penetrate one leaf before it is blocked by the second leaf.

This also assumes that the light intensity is such that it is able to pass through a leaf without causing irrepairable damage to the cells as the light imparts heat energy as it passes through. Just how long those leaves would survive without burning would depend on the variety of plant.
 
Horselover fat

Horselover fat

Well-Known Member
Blue brother said:
This doesn’t seem irrelevant to me, are you taking into account Rayleigh scattering. And also there is so much more reflection happening with a rail fixture hung high than say a cob or hid. Most peoples grow linings are less than the initial 98% claim which doesn’t take into account contaminants that are statically collected on said lining.
Click to expand...
Athmospheric scattering is irrelevant in a grow. Distances are much too short for it to have any effect. Wall losses are a thing. I would want to see reflectors on led fixtures.
 
Kassiopeija

Kassiopeija

Well-Known Member
Blue brother said:
This doesn’t seem irrelevant to me, are you taking into account Rayleigh scattering. And also there is so much more reflection happening with a rail fixture hung high than say a cob or hid. Most peoples grow linings are less than the initial 98% claim which doesn’t take into account contaminants that are statically collected on said lining.
Click to expand...
it is because the light will loose only a tiny fraction of its energy but ultimately each photon will still drive photosynthesis equally as it only needs 680nm or 700nm even 780nm to do so
Blue brother said:
I’ve had no option but to argue the same point for so long which makes me look like a mad man or someone with an agenda. But that’s because I believe what I initially said to be the truth. The point I made certainly doesn’t warrant the amount of times I’ve had to defend myself about it. I stand by it, and I’ll say it again lumens can’t be added because they come from a single source only lux can be the cumulative value.

I’ve also said many times that cobs are closer to single source than qb panels and qb panels are closer than qb strip rail fixtures. But it’s not the electrodes In an hid lamp that are the source it is the arc which is a single source.

It certainly makes me look like an idiot to newcomers of the thread, who are just reading a couple pages with other peoples reply’s which insinuate I’ve bashed led vs hps when I’ve never at any point done that.
Click to expand...
Plants are 3-dimensional though leaves may be appromixated to a 2-d plane.
A singular point light-source is 1-d.
So it's when the light reaches a leaf area where the relevant action is happening. How that light was generated or how a simplified formulae tries to desribe its generation is irrelevant as, all things considered, it's not a realistic representation of the world.
But it may work in the way humans work with it. It's basically like in our worldly situation the Newtonian laws of gravity are still true though you already cannot truely calculate the orbit of Mercur with it. There's an error within it and the greater the dimension we use it breaks down at some point. Same with lumens, it's an ideal formulae. A HPS light-origin is no point either it's a rod. My luxmeter shows different numbers at various sides but at the same distance. It's without reflector.
 
Kassiopeija

Kassiopeija

Well-Known Member
Prawn Connery said:
Firstly, it depends on the translucence of the individual leaf. Even if the leaves are somewhat translucent, your light might only be able to penetrate one leaf before it is blocked by the second leaf.

This also assumes that the light intensity is such that it is able to pass through a leaf without causing irrepairable damage to the cells as the light imparts heat energy as it passes through. Just how long those leaves would survive without burning would depend on the variety of plant.
Click to expand...
though there is some merrit to his point as leaves can be somewhat flexible and react to the light environment. for example, there have been studies comparing leaf chlorophly content indoor vs outdoors and outdoors had way less, so a leaf would allow more light to transmit through. which, considering outdoor the sun is way more harsh, is a method of protection when still being able to run photosynthesis at a max speed

but still, the higher you blast the tops the more will be lost as heat that's why a uniform spread is way better than hotspots coming from individual strong lightsources
 
Prawn Connery

Prawn Connery

Well-Known Member
Kassiopeija said:
Horselover fat said:
I 'm not sure I follow. I would think a point source radiates in a sphere to all directions.
Click to expand...
this is in response of his claim about "but lumen not lux"... like you posted correctly pages ago "lux is lumen over area". he still doesnt get it and is transfixed at a very base formulae that does nowhere correctly describe the situation as is
Click to expand...
If he is talking about a "single source" then the only "true" single source of light must be a single photon emitted by a single atom/molecule – all other sources of light are a combination of photons emitted from a cluster of atoms/molecules. Each of those atoms/molecules occupies a different position in space/time, so therefore these clusters cannot all be from the same SINGLE SOURCE.

To wit: a single photo emits in only one direction.

Addendum: a single photon may have a wavelegnth that falls outside 400-700nm, so is not even guaranteed to be counted in terms of "luminous flux".

If you are going to stick to the dogma of "single source" then you have to be true to its definition. An arc tube, by definition, emits multiple photons from multiple sources of individual ions. Each of those ions is a "single source" of light (electromagnetic radiation).

@Blue brother – what are the parameters of your "single source" argument?
 
Prawn Connery

Prawn Connery

Well-Known Member
P.S. If you are going to hold to your ideals in the face of overwhelming evidence to the contrary, then unfortunately it will appear that the world is ganging up on you. The world is not ganging up on you; your argument simply falls outside the consensus of human logic and current understanding.

It's nothing personal.
 
Blue brother

Blue brother

Well-Known Member
Prawn Connery said:
If he is talking about a "single source" then the only "true" single source of light must be a single photon emitted by a single atom/molecule – all other sources of light are a combination of photons emitted from a cluster of atoms/molecules. Each of those atoms/molecules occupies a different position in space/time, so therefore these clusters cannot all be from the same SINGLE SOURCE.

To wit: a single photo emits in only one direction.

Addendum: a single photon may have a wavelegnth that falls outside 400-700nm, so is not even guaranteed to be counted in terms of "luminous flux".

If you are going to stick to the dogma of "single source" then you have to be true to its definition. An arc tube, by definition, emits multiple photons from multiple sources of individual ions. Each of those ions is a "single source" of light (electromagnetic radiation).

@Blue brother – what are the parameters of your "single source" argument?
Click to expand...
Single source = single source of excitation i.e arc vs multiple sources of excitation I.e many semiconductors

and like I’ve said many times, I know lumens and lux are for humans, not plants. I’m not the one who started using this si. Ppf ppfd are not perfect (if we consider phytochrome triggering by wavelengths outside of the par spectrum) but much better suited to growing plants than lumens. In fact I’d find that a W/S @ specific λ would be a far more useful measurement that we just don’t see in horticulture except in the y of spectral analysis graph.
All I said is we can’t add lumens together from different sources because by definition lumens are measured from a single source. We can add up the lux as it is a measure of light recieved by something. Look at our testing methods, a single hid in an integrating sphere and a single diode in an integrating sphere.
That’s why each diode has its own value and each hid has its own value
 
Last edited:
Blue brother

Blue brother

Well-Known Member
Kassiopeija said:
this is in response of his claim about "but lumen not lux"... like you posted correctly pages ago "lux is lumen over area". he still doesnt get it and is transfixed at a very base formulae that does nowhere correctly describe the situation as is
Click to expand...
I totally understand it, we all know that reception is cumulative. I made one point and yes it was lexically semantic, but I only said it once, more of an fyi. Somehow you either think that lm is the same as lm/m2 or you wanna hang me for being semantic. Which is it? What don’t u think I get?
 
Blue brother

Blue brother

Well-Known Member
Kassiopeija said:
though there is some merrit to his point as leaves can be somewhat flexible and react to the light environment. for example, there have been studies comparing leaf chlorophly content indoor vs outdoors and outdoors had way less, so a leaf would allow more light to transmit through. which, considering outdoor the sun is way more harsh, is a method of protection when still being able to run photosynthesis at a max speed

but still, the higher you blast the tops the more will be lost as heat that's why a uniform spread is way better than hotspots coming from individual strong lightsources
Click to expand...
I totally agree and haven’t ever and would never say anything to the contrary
 
Blue brother

Blue brother

Well-Known Member
To be honest there was a post I made at daft o’clock with a belly fulla rum n ginger beer. That makes no sense at all. And I’m more than willing to point this out as it makes me cringe when I read it back lol

Blue brother said:
Yes I concede. When we talk about intensity as our perception of how many photons hit given surface in a certain amount of time then that is correct and yes we can add this up and we do measure for his in lux (how many photons we can perceive hit our eyes) What I am referring to is the intensity of the wave. The unit is watts/steradian. Energy flux is determined By the output and also the ability of light to move through something, in our case air or leaves. The intensity of the wave is directionally proportionate to the square of its amplitude (sure I’ve got that right… haha it’s been a while). So unless we change the amplitude, we cannot change the intensity. Yes different frequency waves carry more or less energy at the same amplitude but not more intensity. When we add another identical source all we are doing is adding more waves, not changing the amplitude or intensity of the wave.
When we look at luminous intensity all we are doing is counting the number of photons/space/time and forgetting about the wave. We must concerntrate on the wave if we want to determine the power of the light which directly correlates with the distance it can travel or depth it can penetrate.

although I am an optical engineer by trade this was a very long time ago so someone may be able to point out a mistake I’ve made, but I’m pretty sure what I’ve said is solid.

imagine 4 400ppf sources hung 1m above a canopy vs 1 1600ppf source, the amount of photons that hit the be canopy will be very similar resulting in similar luminous intensity (photons/space/time as we perceive) but the stream of photons is not more intense, just the way we perceive them hitting the surface is. There is no way the 4 250s have the intensity to penetrate or “shine” as deep or as “far” respectively as the 1000.

EDIT: I’ve edited this like 4 times since I posted it haha, I am rusty.
Click to expand...
A3CF7582-7FC4-4DD4-B30A-3F0338AA55FC.png
 
Blue brother

Blue brother

Well-Known Member
I am getting tired of this now, so much debate over semantics, I feel I’ve made my point clear. And seeing as there is nothing to be gained by furthering this argument, I’m going to withdraw it. The fact that I’m receiving reply’s with comments like “hardly matters” “for the most part” “irrelevant in a grow” “might only penetrate one leaf” shows an unwillingness to look at my claims in an absolute sense. I never said hid was better than led, quite the opposite actually. I simply stated physical functions of light and also abit of semantics when it comes to the definition of lumen.

It seems everyone just wants to hear leds are better in every sense and hid is shite. No one wants to take into account the physical function of light in absolute terms.
 
S

snakedope

Well-Known Member
Blue brother nailed it better then I can ever do, some folks here don’t like the truth, and it shows and hurts them for whatever reason.

That’s ok with me though, reality don’t lie, ages of knowledge (Blue Brother) can’t be overrun by kids who play with diodes for couple of years
This tech will improve in time I think, for now sticking with HPS/CMH will give the best results, as far as I’ve seen.
 
You must log in or register to reply here.
Top