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

Prawn Connery

Well-Known Member
I'm not going to read any more stupid shit about light intensity. The people who know what they're talking about are the people who know what they're talking about. And it's not the HPS crowd. I have nothing against HPS, but they are old technology and simply do not produce the same quality as LED. They have holes in their spectrum and are not very efficient. They produce buds alright – for 50% more energy consumed – and add unwanted heat to the grow room. Plus they have negligible UV and get pounded in cannabinoid tests commpared to UVA-enhanced LEDs.

I grew under HPS for 20 years, so why would I swtich to LED if I wasn't getting results? It's a bit disingenuous to assume that many LED growers are not already experienced HPS/CMH growers.

Here's some LED porn. All of these were grown under LED lights that I designed, FWIW.

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Rocket Soul

Well-Known Member
Hey Snakeywakey, good morning! Ill happily go next: heres some photos from my buddys grow, i built him the light. The light ran at 100w ans replaced a 400w hps and increased yield, both in absolute amount and in g/w. Diode per diode was it was at at 0.075w per diode, about 10 lums per diode. Thats what, intensity of a full moon? The screen on my phone if im trying to save batteries?
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If those lums dont add up how did he get buds like that? Its would be like flowering in the moonlight. He got about 350g total, so 50 per square foot. Please explain. Also maybe show a grow where you can get similar or better results with hps: ie show me a 4x4 lit by a 250hps and show me about 2 pound yield. Should be easy as you are working with such superior equipment.
 

Blue brother

Well-Known Member
Hey Snakeywakey, good morning! Ill happily go next: heres some photos from my buddys grow, i built him the light. The light ran at 100w ans replaced a 400w hps and increased yield, both in absolute amount and in g/w. Diode per diode was it was at at 0.075w per diode, about 10 lums per diode. Thats what, intensity of a full moon? The screen on my phone if im trying to save batteries?
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If those lums dont add up how did he get buds like that? Its would be like flowering in the moonlight. He got about 350g total, so 50 per square foot. Please explain. Also maybe show a grow where you can get similar or better results with hps: ie show me a 4x4 lit by a 250hps and show me about 2 pound yield. Should be easy as you are working with such superior equipment.
First off I just wanna say well done with that build it looks fantastic, also I want you to know that I am in no way bashing led tech, I use it, I love it, and I agree that it is better in almost every circumstance than hps.
The point I was trying to make is that while we can use multiple smaller sources of intensity(quantum board) rather than 1 source of intensity (hid) and add up the lux (ammount of light hitting a given surface) we cannot add up the lumens produced by each diode as lumens is a measure of how much light is produced by a single source and in all directions

I have a 350r in my 3x3 right now, if I add another and space them out, yes double the photons are hitting that surface, and also yes the canopy will be better lit. And yes we might even notice there is more light reaching further into the canopy, but this is because there are more angles, so where some spots deeper into the canopy are now receiving more light than before, this happens because there are more sources hitting that spot from different angles, often unobstructed vs 1 source having to penetrate through said obstructions.

so yes more lux but not more lumens.

I’m not unwilling to be wrong at all, in fact I thank @Kassiopeija for schooling me as he obviously knows more than I.

and also I’m not trying to be the stick in the mud I just don’t believe that we can add up lumens unless they all came from the exact same spot which is physically impossible. I’m currently awaiting a reply from an optical physicist I chat with from time to time. Hopefully he will shed some light on the matter (pun intended)
 

lusidghost

Well-Known Member
What I've taken away from all of this is that scrogging, lollipopping and defoliating are all probably beneficial to an LED grow. Defoliation would be the most debatable, scrogging would be the second most debatable and lollipopping would be almost undebatable.
 

Blue brother

Well-Known Member
I'm not going to read any more stupid shit about light intensity. The people who know what they're talking about are the people who know what they're talking about. And it's not the HPS crowd. I have nothing against HPS, but they are old technology and simply do not produce the same quality as LED. They have holes in their spectrum and are not very efficient. They produce buds alright – for 50% more energy consumed – and add unwanted heat to the grow room. Plus they have negligible UV and get pounded in cannabinoid tests commpared to UVA-enhanced LEDs.

I grew under HPS for 20 years, so why would I swtich to LED if I wasn't getting results? It's a bit disingenuous to assume that many LED growers are not already experienced HPS/CMH growers.

Here's some LED porn. All of these were grown under LED lights that I designed, FWIW.

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Would absolutely love to see some gla on the market in the U.K. is this something that might happen soon?
 

Horselover fat

Well-Known Member
First off I just wanna say well done with that build it looks fantastic, also I want you to know that I am in no way bashing led tech, I use it, I love it, and I agree that it is better in almost every circumstance than hps.
The point I was trying to make is that while we can use multiple smaller sources of intensity(quantum board) rather than 1 source of intensity (hid) and add up the lux (ammount of light hitting a given surface) we cannot add up the lumens produced by each diode as lumens is a measure of how much light is produced by a single source and in all directions

I have a 350r in my 3x3 right now, if I add another and space them out, yes double the photons are hitting that surface, and also yes the canopy will be better lit. And yes we might even notice there is more light reaching further into the canopy, but this is because there are more angles, so where some spots deeper into the canopy are now receiving more light than before, this happens because there are more sources hitting that spot from different angles, often unobstructed vs 1 source having to penetrate through said obstructions.

so yes more lux but not more lumens.

I’m not unwilling to be wrong at all, in fact I thank @Kassiopeija for schooling me as he obviously knows more than I.

and also I’m not trying to be the stick in the mud I just don’t believe that we can add up lumens unless they all came from the exact same spot which is physically impossible. I’m currently awaiting a reply from an optical physicist I chat with from time to time. Hopefully he will shed some light on the matter (pun intended)
Lux is lumen per area. Like umol/s vs ppfd. The total output of the lamp is one thing and what lands on a given spot is another. It doesn't matter how many sources there are. What matters is how many photons you produce and manage to direct to your grow area.
 

Blue brother

Well-Known Member
Lux is lumen per area. Like umol/s vs ppfd. The total output of the lamp is one thing and what lands on a given spot is another. It doesn't matter how many sources there are. What matters is how many photons you produce and manage to direct to your grow area.
are you saying you can add lumens up? If you had 10 3lm bulbs would you say you have 30lm? So would 10 3lm bulbs at the same height as a 30lm bulb penetrate to the same depth as the 30lm source?
 

Blue brother

Well-Known Member
are you saying you can add lumens up? If you had 10 3lm bulbs would you say you have 30lm? So would 10 3lm bulbs at the same height as a 30lm bulb penetrate to the same depth as the 30lm source?
@Horselover fat
And if so, then why does a rail fixture need to sit closer to the canopy than a hps to achieve desired results?
When we use a rail type Led we are essentially spreading out the hot spot to more evenly cover a flat plane, but we can’t have it both ways, it can’t simultaneously penetrate as deep as the hps with its central hotspot and evenly spread that hotspot around the area we are trying to light. It has to be one or the other.
 
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Horselover fat

Well-Known Member
are you saying you can add lumens up? If you had 10 3lm bulbs would you say you have 30lm? So would 10 3lm bulbs at the same height as a 30lm bulb penetrate to the same depth as the 30lm source?
I think it makes more sense to talk about photons instead of lumen. But, yes, ten times the light is ten times the light. The light is then spread to an area. Changing the area the light lands on changes the intensity (lux/ppfd). If you take the multiple sources further from each other you increase the area the light lands on, which decreases intensity. Same thing happens if you light up a larger area using a single source.
 

Blue brother

Well-Known Member
I think it makes more sense to talk about photons instead of lumen. But, yes, ten times the light is ten times the light. The light is then spread to an area. Changing the area the light lands on changes the intensity (lux/ppfd). If you take the multiple sources further from each other you increase the area the light lands on, which decreases intensity. Same thing happens if you light up a larger area using a single source.
Right I’m following what ur saying, so when we use a rail type fixture we’re increasing the uniformity of intensity across the canopy?
but if we use a single source we’re increasing the intensity in the Center?
So if there’s more intensity in the Center would it not be fair to say that we are penetrating deeper into the canopy at that point than we would with multiple sources that all total the same power value?
 
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