3000k vs 4000k

Prawn Connery

Well-Known Member
Nice looking buds! What do you feed those girls?
The big room is fed a mixture of Hygen nutrients, including Budlink silica additive, and Monster Bud. It's actually a commercial grow run by a friend which I have a hand in. I designed and helped set up the room, did the clone selection (Paradise Seeds Wappa), and built the LED panels (2x QB324 per frame, each running 400W off a HLG-480H-C2100-A driver).

The tent grow is fed Candadian Xpress, which is a hybrid organic nutrient (micronutrient Part A and organic Part B), with Budlink under 400W of Samsung H-Series strips (x24) driven by 2x HLG240H-48-A drivers.
 

Prawn Connery

Well-Known Member
a hps or a cmh would be 10-15x better and u will save yourself bout 800 bucks
Hey nob333, I just had a look at your shit-stain gallery: https://www.rollitup.org/Journal/rob333.182056/

You're a fucking joke! Are you honestly proud of your pissant little chickenwire grow? What gives an amateur like you the authority to lecture anyone about grow lights? You couldn't grow to save your foreskin!

So here's nob333's efforts at growing plants. Or should that be noob333? Sorry, I can't help myself calling out wankers for what they are.
 

Humple

Well-Known Member
Hey nob333, I just had a look at your shit-stain gallery: https://www.rollitup.org/Journal/rob333.182056/

You're a fucking joke! Are you honestly proud of your pissant little chickenwire grow? What gives an amateur like you the authority to lecture anyone about grow lights? You couldn't grow to save your foreskin!

So here's nob333's efforts at growing plants. Or should that be noob333? Sorry, I can't help myself calling out wankers for what they are.
You mean you can't see that his results are 10-15x better?? He's clearly a master grower!

In all seriousness, I'm guessing he won't be back in this thread (though it would be entertaining if he actually tried to back up his claims now that he's been called out).
 

Flowki

Well-Known Member
Hey nob333, I just had a look at your shit-stain gallery: https://www.rollitup.org/Journal/rob333.182056/

You're a fucking joke! Are you honestly proud of your pissant little chickenwire grow? What gives an amateur like you the authority to lecture anyone about grow lights? You couldn't grow to save your foreskin!

So here's nob333's efforts at growing plants. Or should that be noob333? Sorry, I can't help myself calling out wankers for what they are.
Well he kinda did deserve a fire with fire approach, it rhymes with chicken wire so it must be true.
 

mauricem00

Well-Known Member
A bit beyond the numpties, but for anyone else this makes interesting reading. Also, no mention of LEDs.

https://www.researchgate.net/publication/233965860_INFLUENCE_OF_LIGHT_WAVELENGTHS_ON_GROWTH_OF_TOMATO
interesting that this study did not test 430nm, the chlorophyll A ps2 absorption peak. they only tested what LEDs can produce efficiently. many 1596215591458.pngcompanies use junk science to sell their products, I wonder who paid for this study? plants have close to 400 pigments and use a wide range of light
 

Prawn Connery

Well-Known Member
interesting that this study did not test 430nm, the chlorophyll A ps2 absorption peak. they only tested what LEDs can produce efficiently. many View attachment 4640340companies use junk science to sell their products, I wonder who paid for this study? plants have close to 400 pigments and use a wide range of light
I'm not sure I've seen that graph before. It is quite different to other, more common plant absorption graphs – though this one appears dedicated to cannabis and not other plant species. Where is it from? Is this total absorption of all combined photosynthetic pigments? Ie, Chl-A, B, Carotenoids etc?

This is an old thread, but the study I linked to is from 2012 so is pretty dated. I'm assuming the reason they chose the LED wavelengths they did is because they were the most common/economical/efficient LEDs available at the time. Things have moved on since 2012, but it is still commonly believed that total photons > spectrum, which is why efficiency is still regarded as > than spectrum.
 

f series

Well-Known Member
Fuck it I'ma jump on this old posting bandwagon, that dude said his plants suffer in flower under 4k vs 3k...... suffer?..
 

Prawn Connery

Well-Known Member
If you read through this thread I sound a bit harsh. But the guy posting the stupid shit about HPS being "10-15x better than LED" was at first thought to be a LED troll, but later discovered to be slightly off his rocker. If I'd known that then, I probably wouldn't have gone so hard on him.
 

mauricem00

Well-Known Member
I'm not sure I've seen that graph before. It is quite different to other, more common plant absorption graphs – though this one appears dedicated to cannabis and not other plant species. Where is it from? Is this total absorption of all combined photosynthetic pigments? Ie, Chl-A, B, Carotenoids etc?

This is an old thread, but the study I linked to is from 2012 so is pretty dated. I'm assuming the reason they chose the LED wavelengths they did is because they were the most common/economical/efficient LEDs available at the time. Things have moved on since 2012, but it is still commonly believed that total photons > spectrum, which is why efficiency is still regarded as > than spectrum.
in this video half the photons produce more growth due to better spectrum
the graph is from Columbia.plants have close to 400 pigments.this graph shows absorption for all of them. this belief is more bro-science plants can adapt to any form of light but provide better taste and potency with an SPD that LEDS and HPS can not produce some growers supplement these lights with UV bulbs with the right SPD plant can flower well with only 2500 lumens/sqft
and
 

Prawn Connery

Well-Known Member
in this video half the photons produce more growth due to better spectrum
the graph is from Columbia.plants have close to 400 pigments.this graph shows absorption for all of them. this belief is more bro-science plants can adapt to any form of light but provide better taste and potency with an SPD that LEDS and HPS can not produce some growers supplement these lights with UV bulbs with the right SPD plant can flower well with only 2500 lumens/sqft
and
Your videos don't appear to dispute what I wrote. For a start, the UVB bulb could well be throwing out 3x the photons of the test bulb, but we will never know, because they used a standard PAR meter that does not read anything above or below 400-700nm.

Also, your reference to "2500 lumens per square foot" could mean anything when the spectra you are using is not weighted towards 550nm, where lumens peak, and may or may not fall outside the visible range, or may be weighted towards either end of the PAR range. I would count wavelengths outside 400-700nm in the PAR range, but that's another story.

I don't know if you're going to convince anyone that fluorescent bulbs can outperform LED. Their efficiency sucks and the only way to tune the spectrum is with phosphors.

Is that what you're trying to tell us? That fluoros are better than LED? Apologies if that is not what you are saying, but that's the way i read it.

BTW, LEDs can produce any spectrum fluoros can: it's just a matter of cost, efficiency and mixing the right LEDs. I guarantee those LEDs will last longer than those fluoro bulbs, too, which will start to degrade in performance almost from the time you turn them on.

We've done a bit of research into spectrum also, so note I am not saying spectrum is not important. And I didn't say PAR > spectrum – I said "photons > spectrum" and it is a generalised comment when talking about reasonably comparative lights. Obviously hitting plants with a high source of blue is likely to be more detrimental than hitting them with a lower does of full spectrum. It's about perspective.
 

mauricem00

Well-Known Member
just providing evidence that spectrum matters. the power veg provides half the photon output of a standard bulb with better growth. for a low budget PU MMJ grower T5s work well. they outperform cheap ebay LEDS
 
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wietefras

Well-Known Member
just providing evidence that spectrum matters. the power veg provides half the photon output of a standard bulb with better growth. for a low budget PU MMJ grower T5s work well. they outperform cheap ebay LEDS
Bugbee did some tests and he saw that greens would benefit from more blue in the spectrum (something like 10% more yield). Whereas flowering/fruit bearing plants would yield much better (up to 25% more yield) with less blue in the spectrum. So spectrum does matter indeed.

That PowerVEG light seems to put about half of the SPD in the under 400nm Category. Maybe that confuses things.
 

Oakiey

Well-Known Member
Heck for veg I wouldn't even put anything lower than 5000k over a fish tank.

I've got a brand new 400,w 4000k bulb in a drawer, I swear my plants just almost shutdown underneath it...
 

xxEMOxx

Well-Known Member
For veg ive always used 6500k t8 or t5 flouros for the extra blue and it works well.

For LED i tend to prefer a 2:1 ratio of 3000k to 4000k. So basically 2 3k boards 1 4k board. I personally think this balance has been the most productive.

Also this whole HPS vs LED isn't true anymore, it takes about 450ishwatts LED to equal my 600hps in magnum hoods. But so far the quality, density, and yield has been just as good if not a little better then my HPS produced, and depending on your led light design can produce much better coverage footprint.
 

mauricem00

Well-Known Member
You are confusing absorption with photosynthetic efficiency.
if the plant is absorbing the light I assume they are using it for something. UVA helps plants absorb calcium from the soil which may explain the cal-mag deficiency seen with LEDs. the 365nm LEDs I found on amazon have an efficiency of 4.5% (1200mw input 55mw output) with an instant start ballast a T5 HO has an efficiency of 30% even in the UV range.high end LEDs have an efficiency of 40% the new 301 can achieve 50% with 4000k to 5000k and 46% with 3000k or 43.7% with a meanwell driver high quality LEDs are outside my budget T5s are cheap and effective.for a large scale grow I would use CMH
 

Oakiey

Well-Known Member
I'm not sure about the cmh, it got like 17000 fewer lumens than a 400w HPS

How in the hell is it supposed to replace a real 600 wat light?
 

Rocket Soul

Well-Known Member
if the plant is absorbing the light I assume they are using it for something. UVA helps plants absorb calcium from the soil which may explain the cal-mag deficiency seen with LEDs. the 365nm LEDs I found on amazon have an efficiency of 4.5% (1200mw input 55mw output) with an instant start ballast a T5 HO has an efficiency of 30% even in the UV range.high end LEDs have an efficiency of 40% the new 301 can achieve 50% with 4000k to 5000k and 46% with 3000k or 43.7% with a meanwell driver high quality LEDs are outside my budget T5s are cheap and effective.for a large scale grow I would use CMH
High end leds are over 50% efficient for a few years now. you can even get 365nm LEDs that are close to 50%: https://www.digikey.es/product-detail/es/new-energy/LST1-01G01-UV01-00/1672-1123-ND/7926550 .
 
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