25% more yield with a diffused LED ?

[Ca++]

This heat radiation talk is irrational. Just put your hand there. The whole reason LEDs are efficient, is because they waste much less power making heat. People are adding extra one's specifically to add heat radiation. They are warming their rooms more to make them work.

If there is a connection to heat, it's a lack of heat. Photosynthesis leads to moisture loss. So more light will lead to more water loss. If there was heat, the plant might actually close up it's pores a bit. Limiting this water loss. It's dehydration of the guard cells that slows moisture loss. K is often connected with water regulation by existing here. Lately drought stricken areas have relied on Cl to reduce water losses. If growing in 20% RH and finding increased photosynthesis leading to water loss, then it's worth looking at. Most LED users find themselves much more concerned with temp and RH than ever before, as they battle to keep transpiration in line. Finding losses too great in a 20% RH room isn't surprising. Owning LEDs and thinking there is a heat radiation problem is though.


The speed with which peoples plants go pale and drop is really something when it happens. It has similarities to P toxicity. I would love to see tissue samples. Though it may be just bleaching, as processes collapse. Boy, do they collapse sometimes. RH is the real key to slowing moisture loss. It's one of the few controlling factors we can work with.

I have cobs I might cover. They always end up too close anyway, and have power in reserve to overcome any losses. It's almost off topic though.

There seem to be two schools here. One looking at diffusers to increase the number of angles the light comes from. Another want's to mix the colours more.
If we use a lens to add divergence, we have any satisfied the former. The latter may be made worse.

 

[GoatCheese]

By adding calmag and epsoms didnt the whole npk profile change due to the ratios between the elements?
I mean most of calmag have N and some also Fe, i can understand how N P and K isnt the same as Ca and Mg but since us adding them the ratios are different so the profile should be different? Did the question is stil wrong?
Some say B help moves Ca in the plant, did you ever tried it? I ask even tho you use Biobizz because it should work the same.

Also since the the temp and rh affects the vpd and it should be in balance with the lights and also the nutrients i think its normal they suffer, the parameters are wack for what they need.

Again, i dunno what leds Dr. Bugbee did is trials with healthy growing seedlings with high ppfd like flowering, but he did said all the parameters should be in check with that, lower ppfd and same parameters as high ppfd i guess they suffer and the other way around so in my newb curious mind we are missing just the balance for what they need at the different spectrums, either food, vpd, co2, air exchange etc etc..

Any opinions?
Again dont take me as a smart ass, i dunno squat, just curious learbing from all of you.

Peace

Well, Fe, Mg, Ca and B aren’t part of the NPK profile - nitrogen (N), phosphorus (P) and potassium (K)

You mean i use more nitrogen now with leds cause i use calmag compared to when i didn’t use calmag during HPS days?

I have dropped my N levels since those days in general – less BioBizz Grow in bloom – and i have started using PK13/14 to replace some of that N in late bloom, so i feel my N levels have actually still gone down from the HPS days growing the same cuttings.- They yellow out earlier nowadays in late bloom because of the lower N levels.
I also stop using calmag when i stop giving my plants BioBizz nutes weeks before harvest. Then they only get BioBizz TopMax and plain water for the last 5-ish weeks before harvest.


And now i have given my soil and coco plants the same amount of calmag during led times, so the only difference is the moisture content in the plant’s system that keeps the coco plants in better shape than my soil-plants.

-

-

I’m not directing this at only you, Sampas92, so don’t take offence, bro.

..but you guys seem want to talk about everything else regarding leds than the TOPIC of this thread which is diffuser-materials and modern leds.

I’m gonna come back when i have set up those diffuser sheets under my veg lights, i just don’t have any interest in light movers or nutrients+leds talk (been there) or explaining to people how it’s possible they can breath in their grow rooms.

Peace. Later..

 

[Koondense]

No need to explain anything, nobody is asking really

 

[Sampas92]

Well, Fe, Mg, Ca and B aren’t part of the NPK profile - nitrogen (N), phosphorus (P) and potassium (K)

You mean i use more nitrogen now with leds cause i use calmag compared to when i didn’t use calmag during HPS days?

I have dropped my N levels since those days in general – less BioBizz Grow in bloom – and i have started using PK13/14 to replace some of that N in late bloom, so i feel my N levels have actually still gone down from the HPS days growing the same cuttings.- They yellow out earlier nowadays in late bloom because of the lower N levels.
I also stop using calmag when i stop giving my plants BioBizz nutes weeks before harvest. Then they only get BioBizz TopMax and plain water for the last 5-ish weeks before harvest.


And now i have given my soil and coco plants the same amount of calmag during led times, so the only difference is the moisture content in the plant’s system that keeps the coco plants in better shape than my soil-plants.

-

-

I’m not directing this at only you, Sampas92, so don’t take offence, bro.

..but you guys seem want to talk about everything else regarding leds than the TOPIC of this thread which is diffuser-materials and modern leds.

I’m gonna come back when i have set up those diffuser sheets under my veg lights, i just don’t have any interest in light movers or nutrients+leds talk (been there) or explaining to people how it’s possible they can breath in their grow rooms.

Peace. Later..

Bro no offense dont worry, like i told you im a newb knowing nothing but i like to think and learn and discuss and even if the thread diverged a bit from the topic i think all of this chat between all of you is correlated somehow.

Of you dropped you N levels but added Calmag that have N then the NPK profile may be the same.
What i was saying about the ratios is because as you know higher or lower ppm of x element affects the avaiability of y element, while the profile may not changed for us in paper for the girls it is.

While you are saying you dont see a food problem, @Ca++ said that heat raditation made the spores close more, retaining moisture and less dehidratation, so if the problem is them sweating too much and we know that we need to adjust the feed higher or lower as they sweat/drink more or less, but they also are more hungry because leds makes them push harder so more food they need
It seems the problems are not the leds and is us not getting the parameters right for the leds ence some people seem to be getting good plants feeding them hard, being in coco hydro or organics.
I remember some user in ic talking about 421 ratio of K to Ca to Mg that works wonderfull under leds but at higher ec's, 2+.

If stronger feed works how can the problem be the leds?

Peace

 

[Sampas92]

No need to explain anything, nobody is asking really

Bros dont get "angry" at each other, ic historically was know by a bunch of people with an healthy arguing reaching conclusions, the contrary of other forums.

I feel everyone somehow seems right just missing the links between.

Peace

 

[Cerathule]

I love photobiology. This is were we will still see great improvement developing during the next +30 years.

An excerpt from the attached study:

"Far-red light was projected from above onto the leaf through a diffuser, so that a circular leaf area with a diameter of 4 cm or greater was uniformly lighted. The incident far-red light intensity was measured using a silicon power sensor (S140A; Thorlabs, Newton, NJ) connected to a power meter (PM100; Thorlabs, Newton, NJ). The measured power was converted to photon flux density (PFD) based on the amount of energy contained per mole of photons at different wavelengths and the area of the power sensor sensing area."

>> It stands to reason that a non-uniform lighting of a leaf could result in locale distortions of the photosynthetic process, ie. when excess light is gradually quenched more via heat emission or fluorescence. It's the basis to not measure fluctuative data.

The idea of a large surface from which photons emerge is intriguing, it's what makes t8 so easy to use, plus plants there develop nicely. But any lost photon still us lost (to heat) and that is opposite of what LED technology seems to aim for.
Increasing diode count is another way to more diffuse radiation. Think: underdriven diodes everywhere. The associated hardware costs will come down with time.

Another way to make the most out of it could be, as the study did confirm, to use a light-recipe consisting of colours that will increase carbon-fixation more than "just white light", and numerous studies all confirm the very same thing, that this is with far-red light.
They narrow it down to a region directly after the famous 'red drop' that is 700-730nm where Photosystem I prefentially gets excited much more than Photosystem II.

There are many other benefits of having farred on board, photoprotection (less bleaching, heat reduction, phytochrome effect, strong penetration into the mesophyll or lower parts of the plant and a potentially very economical way to generate these wavelengths once the technology follows up on science.

 

[Ca++]

I have seen a number of Far red experiments with cannabis specifically. Non have born fruit. Cannabis just likes light. Lots of it. It's desire for even amounts of each, like sunlight, suggest Both IR and UV should be as sunlight levels. Cannabis just seems to see the same as we do though.

People keep trying to separate their product from the next mans. So these UV and IR tests will continue. Some of looked closely at weight and at secondary metabolites. Used them in ways the sun will of never done, in efforts to get a response. People really want it to work, but Cannabis..... lazy.

 

[goingrey]

I love photobiology. This is were we will still see great improvement developing during the next +30 years.

An excerpt from the attached study:

"Far-red light was projected from above onto the leaf through a diffuser, so that a circular leaf area with a diameter of 4 cm or greater was uniformly lighted. The incident far-red light intensity was measured using a silicon power sensor (S140A; Thorlabs, Newton, NJ) connected to a power meter (PM100; Thorlabs, Newton, NJ). The measured power was converted to photon flux density (PFD) based on the amount of energy contained per mole of photons at different wavelengths and the area of the power sensor sensing area."

>> It stands to reason that a non-uniform lighting of a leaf could result in locale distortions of the photosynthetic process, ie. when excess light is gradually quenched more via heat emission or fluorescence. It's the basis to not measure fluctuative data.

The idea of a large surface from which photons emerge is intriguing, it's what makes t8 so easy to use, plus plants there develop nicely. But any lost photon still us lost (to heat) and that is opposite of what LED technology seems to aim for.
Increasing diode count is another way to more diffuse radiation. Think: underdriven diodes everywhere. The associated hardware costs will come down with time.

Another way to make the most out of it could be, as the study did confirm, to use a light-recipe consisting of colours that will increase carbon-fixation more than "just white light", and numerous studies all confirm the very same thing, that this is with far-red light.
They narrow it down to a region directly after the famous 'red drop' that is 700-730nm where Photosystem I prefentially gets excited much more than Photosystem II.

There are many other benefits of having farred on board, photoprotection (less bleaching, heat reduction, phytochrome effect, strong penetration into the mesophyll or lower parts of the plant and a potentially very economical way to generate these wavelengths once the technology follows up on science.

A lot of the new LED lights do have some far right diodes. Maybe all of them? Not quite sure if enough for real or just marketing benefits.

This is the spectrum of the lamp I'm using.

 

[Koondense]

Hi Cerathule,
nice post.
I remember in 2015 when the cob led mania started on the forums, there were many camps on how to utilize the cobs and what kind of fixtures should be used for cannabis.
Some were in favor of more is more, so more efficient cobs were used, later side by side experiments confirmed the idea that spectrum or main colors ratios were more important than just lumens.
Some went in the direction to build a huge cob with additional mono LEDs...

To keep it short...
I opted for the naked design, no optics and just cob on heatsink. It still works excellent like the first day I made them.
The idea was and still is to simulate diffuse lightning with many underpowered big cobs,the biggest at the time were Cree cxb3590 which were then surpassed in efficiency by the Samsung smd line used in so called quantum boards.
The point is, diffused light is good but not if made with sacrificing efficiency.
The light fade gradient should still be lowered by more beams(many cobs, later many smds) but the overall system efficiency remained high(2,3 umol/J). Diffusers can easily lower it by 5-15%, even regular lenses lowered it by 2-5%.
So yeah, I get it that diffusers are a kind of cheap solution but I'm not really a fan of it.
One of the important parts of growing is canopy management and using cobs and qbs requires some manipulation of tops, which is another interaction between grower and plant, it lets you know them better.
Oh yeah,far red... It is in fact a solution to low CRI white LED systems. We know low cri LEDs are cheap so adding some more cheap for monos is adding value to overall light quality, but are there benefits for cannabis? Hard to say,my opinion is no. Since I use just white cobs and get excellent results, what can be the point to add reds which will even more elongate my sativas? In a way it's a waste of electricity

The lightning evolution still goes on and I'm eager to see what will be on the market in 2025 and beyond...
Meanwhile diy rules,especially when you experiment with it...

Cheers

 

[Cerathule]

Thanks for kind responses, hope I'm not derailing this thread.

The phytochrome farred excitation will only result in the Hyper-Intensity-Reaction/etiolation if no stronger 660nm is present, which causes a photoconversion. The HIR has several fluence levels, and dependant on the Pr-to-fr-ratio plus the luminous flux of the farred radiation in the total spectral power different reactions can occur. Also the bluelight-receptors can partially mitigate this effect, esp. if the blue manages to reach a tad deeper into the canopy.

So we need to differentiate strongly between red and darkred as these 2 do different things for the plant although they are quite close together. It can get confusing sometimes as various branches or systematics use different terms for the same color, e.g. "photored" "red" "bright red" for 660nm diodes or farred for darkred or N-IR 730nm.

The 660nm diode is currently the most efficient with a quantum efficacy of ~4.3umol/J. A strong 660nm spike sets the precondition for even a wider shift into farred, either through low-CRI diodes (lm301h-ONE) or monochromatics.
Both is viable, though monochromatics give the possibility to do a 730nm end-of-day on a separate channel, which will increase flowering hormone levels and some tests show also budding out & ripening time.

Many studies proof that farred light beyond the red drop (-780nm) is still photosynthetically viable and may even act "like a catalysator" in the presence of white light (360-680nm). This was first found by Emerson but later forgotten as the phenomenum not understood due to the general lack of knowledge in this field.
Bugbee et al tested this recently and found increased carbon fixation gains in the range of 200-500%, measured for each quanta of farred vs the PS1 light (white or RedBlue).
This means you put a 730nm diode up that may deliver up to 3umol/J but its benefit is like the equivalence of 6-15umol/J of generic white light.

Lots of arguments for efficiency...
Well, if one were to diffuse light using wasteful screens or lenses it stands to reason to use wavelengths that are tendential more "easy to massproduce" and then, more readily absorbed (as the leaf looses some form of control of regulating its input e.g. via the Sieve-mechanism in dicots based on chloroplast translocation)

Another way to cause light diffusion is by integrating colors that have a higher reflectance or transmittance, and this is farred, green (and UVA). It's just to saturate places where blue or red won't reach much, deeper into the leaf mesophyll, some of that bounces internally (Detour-effect) though the photon may as well be deflected or transmitts to just be absorbed somewhere else.

Yeah well there are quite a number of SPDs out there already harnessing both 660 & 730nm with success, plus the sun also has a massive 1.2:1 R:FR-ratio, though a tropical Sativa may need way more blue and is used to high irradiance in its natural habitate.
Here, LED still need some major technological advances in the form of efficient broadband blue or white diodes that cover the whole cryptochrome/phototropin/ZTL absorption specs ~~ 340-590nm.

 

[Koondense]

That's great info Cerathule, I'll dig deeper in it one day.
Keep it coming

Cheers

 

[GMT]

Sorry to revisit this but this caught my eye. I should have turned another light off to photo this, but......
Light exiting a wavey air vent is wavey on the floor, even though the light source is rigid and not in a direct line of sight.

 

[Three Berries]

 

[Koondense]

It's amazing what human minds can do!

https://arxiv.org/pdf/1509.02890.pdf

Cheers

 

[Cerathule]

If I place a quantum sensor at a leaf it measures a specific value. But unlike the leaf, the sensor isn't able to catch the diffuse photons coming also from left, right, front, below etc pp.
Shouldn't those all add up realistically?

 

[Ca++]

A lot of the new LED lights do have some far right diodes. Maybe all of them? Not quite sure if enough for real or just marketing benefits.

This is the spectrum of the lamp I'm using.

This pic is almost generic. A typical output of many lights, at a glance.
The orange/red peak is too far ahead of the blue and green. As we ramp up the power, this becomes damaging to the point where the plant can't keep up repairs. It's not like the flat-line plot of the sunlight plants evolved to use. Tests are suggesting that lowering that peak would increase yield, even though it's less light.

What am I saying? How can we, here, start to accommodate that idea into what we know.
Lets look back at sodium lighting. It was a lot of orange. It was much more capable of growing the albino bud that raised red leads to. Once the plant can no longer make repairs. An act that was itself a waste of growing time.
What else does our time with sodium show us? Well the change to LED had peoples yields increase, even with less light. Even before LED we had the short lived 315 era. Again, less but better balanced light yielding more.
There is a volume of evidence we can both read about and seem that tells us too much red leads to a plant wasting time on repairs, that ultimately leads to failure if we push hard enough.

When we again look at the light falling upon the wall, painting red stripes, it's easy to see how some plant material has red that much more than 40% of the overall illumination. It might even be better to not have that red light and the repair bill it brings.

My next QB boards will not have reds unless paired with the 301-EVO.
I like the QB lights, as this will be my third set of 288 boards for some, as I learn what I actually what.

 

[Ca++]

If I place a quantum sensor at a leaf it measures a specific value. But unlike the leaf, the sensor isn't able to catch the diffuse photons coming also from left, right, front, below etc pp.
Shouldn't those all add up realistically?

This is very true. I have more lights than the one's above. For me, it's not just about some scatter a light meter misses, I have entire light units being missed due to the directivity of the sensors in use. However, these are just rough ideas these meters offer us. A way to get near industry averages, before getting where we want to be. Then importantly, find our way back their. When we look at the true accuracy of them, we shouldn't pay too much notice to what they say anyway. It's just one of many useful guides we have. Like the PPM meter. It's close enough to be useful.

 

[sshz]

I would think the easiest form of diffusion would be to raise the LED up higher.

 

[Ca++]

I would think the easiest form of diffusion would be to raise the LED up higher.

Seems logical, but look at the red spots on the floor. Why are we seeing them at all, and more height just makes them bigger. It doesn't erase them. The light just keeps going in straight lines. So the height isn't actually mixing the light better at all.

It's very odd. I'm sure the explanation will seem obvious when we have it, but explaining it won't make it go away


Edit: On my most recent panels, I didn't get the latest reds as the divergence angle was quite tight. Not 120 degrees, but something way tighter that I forget. It made me not buy them though. It's conceivable, that raising the lights will diverge the white much faster than the red, if it has a tighter beam angle

 

[goingrey]

Seems logical, but look at the red spots on the floor. Why are we seeing them at all, and more height just makes them bigger. It doesn't erase them. The light just keeps going in straight lines. So the height isn't actually mixing the light better at all.

It's very odd. I'm sure the explanation will seem obvious when we have it, but explaining it won't make it go away


Edit: On my most recent panels, I didn't get the latest reds as the divergence angle was quite tight. Not 120 degrees, but something way tighter that I forget. It made me not buy them though. It's conceivable, that raising the lights will diverge the white much faster than the red, if it has a tighter beam angle

The radiation pattern for the red diodes in question is narrow?

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