25% more yield with a diffused LED ?

[Kimes]

First, this is what I mean by diffused led:

From here:



There are studies online that diffused light is better compared to ones without...

I am no expert, but would love to hear from others whether they benefitted from diffusing lights, especially LED´s.

I have noticed that plants generally feel happier and dont stress so much... Also less need for calmag compared to non-diffused... Others..?

 

[Switcher56]

 

[SuperBadGrower]

One thing is for sure: you don't need a lens or other kind of covering to diffuse the light when it comes to spread out bar-style LEDs

In fact, many bar fixtures released today might even "benefit" from some way to slightly focus the light, because it shoots out at a very wide angle.

Anyway, diffusion is probably not the purpose of those coverings in that video. If you look at 28:15, you'll see one fixture without its covering, right next to Mr. Canna Hat. It has exposed wiring on the canopy side and, honestly, looks like a bit shoddy DIY, sorry to say. (Hey it was 2018)
They would have had to cover them up to keep the LEDs and construction safe from water and damage...

edit: FWIW it does look like the material on the redder lights is more diffusing, and since they use 4x 50w strips per light, there might be a bit of hotspotting to remedy. Its not an optimal construction at all. Modern lights in the same style use way more diodes at lower intensity

I used to have a study about light diffusivity in greenhouses but I can't find it anymore. Diffusing the light improved plant performance (yield) in it. most of those studies are about sunlight in greenhouses and it makes for a less than ideal comparison.

IMO diffusion of light is better, but as I said, if you use a bar style light, or most LEDs in general, its already diffused. The leaves at the edge of the area should be pointing up, unlike with HID lights where the leaves at the edge will be pointed towards the light source (the middle of the area)

 

[Sampas92]

In all my newbiness, but purely logical. If the ppfd levels are the same from difused to not difused and get improvements, than yes maybe its better, if the ppfd of them covered is lower, shouldnt they be better just because they were only being push less?

Peace

 

[f-e]

My browser denies me the video, but they look like some old bulkhead fittings. Likely reclaimed from a skip and converted to LED.

Is there some before and after like yield comparison?

Them older covers are blocking lots of light. Even the polycarb one's are blocking quite a lot. What does come though is helping to light the walls better. It's a lot like knocking the diffuser off a domestic lamp. Gains are seen in the 25% range, not losses. It's been seen by growers far and wide, many times. Enough to call it solid proof.


@Sampas92 good call. Reducing light has certainly helped many people that didn't realise they had too much to handle.

 

[Koondense]

Diffusing a light source(-s) with some kind of lens will only lower the total light output(also the ratio of wavelengths, like IR and UV).
In my opinion it's not logical to expect more yield with this, would expect the contrary.
It's more about canopy management in relation to the light intensity gradient.

Cheers

 

[GoatCheese]

I think light defusing could help, cause getting rid of hot spots (concentrated light beams) creates less stress for the plant –and modern high intensity leds seem to be a big stress factor unless you have near perfect enviro conditions in your grow space and use extra CO2.

Sure there are diffusers and then there are diffusers, so if people are going to use something they should use good quality stuff. Good quality diffusers take only few % off the light intensity.

It would be cool to see a side by side grow

 

[Volcanna]

Diffusing a light source(-s) with some kind of lens will only lower the total light output(also the ratio of wavelengths, like IR and UV).
In my opinion it's not logical to expect more yield with this, would expect the contrary.
It's more about canopy management in relation to the light intensity gradient.

Cheers

But it might allow you to run higher wattages with out the damage from over intensity.

 

[Volcanna]

Fohse leds get the giant yields and they have some proprietary diffuser lens on their diodes.

 

[Koondense]

But it might allow you to run higher wattages with out the damage from over intensity.

But what is the point to use more watts for less light?
Would only work well with small colas and would still be better to just lower the total watts and not use diffusors.

 

[Switcher56]

But it might allow you to run higher wattages with out the damage from over intensity.

... bigger is not always better.

 

[GoatCheese]

Lowering wattage won't get rid of hot spots (concentrated light beams), they just become less intense

 

[Volcanna]

whats gonna yield more 1500w with diffusers or 630w with bare diodes?

 

[SuperBadGrower]

put your hand between a light and the plants, does it cast 1 solid shadow? No ... congratulations, you already have diffuse light


count the light sources in your grow (A diode is a light source)
Is there more than 1 light source. Congratulations, you have diffuse light (Unless they are crammed into 2 inches like a COB obv)

 

[GoatCheese]

^^^^

Maybe you’re confusing a ‘ray of light’ vs a ‘beam of light’?

Surface of single led/light emitter is larger than a single photon, so it does not emit only a single ray of light but several of them at a time which is called a beam.

What is the difference between light ray and light beam?

The light traveling in any one direction in a straight line is called a ray of light. A group of light rays given out from a source is called a beam of light.

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Direct and diffuse light

https://www.stemmer-imaging.com/en/knowledge-base/direct-and-diffuse-light/

Direct light has an uninterrupted path between the source and the target. If the source of the light is a point source, as is the case for LEDs, this will cause a light spot or brighter patch in the middle of the object which is normally not desired. While this can be compensated later in software, it is easier to produce even illumination from the start.

In this diagram, light has passed through a translucent diffuser which softens and disperses the light, creating a more even illumination. The only down side when using a diffuse light is that the intensity is often reduced. Most suppliers of illumination products for imaging purposes will supply different versions of their lights either with or without diffusers.

In this diagram, light has passed through a translucent diffuser which softens and disperses the light, creating a more even surface illumination.

 

[Kimes]

All very interesting comments. Thank you all. Really liked the @GoatCheese image, this is exactly what I had in mind. Light movers achieve this, but cost may be too much for some growers, hence the diffusion film etc. can come handy if desired.. Especially if they just scatter not block so much... idk

Hope this topic does stay civil.. Enouff fighting in the world...

 

[Sampas92]

I still maintain the same opinion, if they yield more then either they werent in a proper feed or lacking something else.
Raising watts on covered leds you spend more for the same ppfd without the covers.

I remember when people started using cobs..one per 60x60 tent..more cobs in a bigger tent would give hotspots..i remember people raising them..until the lens come around, spreading the light more, reducing the ppfd where it was stronger and raising it where it was lower..

I guess is the same logic when people are burning plants under leds and they reduce the light power, the plants got better and they yield more, but just because all of the other variables, feed, environment etc becoming rught to that lower light scource..so the problem is the light or the rest?

Not like hps and closed hoods tho, temps got lower and people get the light closer for the same output, there the yield increased but the problem was the heat..problem with leds seems to be environment and the feed requirement.

I mean, im nobody in the growing scene, hobby whatever you guys can call it..but this grow, im on coco for the 1st time, powder salts..my fce3000 on a 1mx1m tent is at 100%, distance of 20cm of the highest tops, ppfd ranging from 1000 to 1300, of course lower on the sides
They are not the best grown plants for sure, im just newbin, but i never got them that healthy under that much light in flowering, and this ones are middle of preflower

So the problem seems its not the leds intensity or difusion, i mean, there are studies where seedlings where getting huge ammount of light for that stage, the other requirements for such light output where on pair and the seedlings growed normaly, so (Dr. Bugbee on Youtube)

Peace

 

[Koondense]

Imo, GoatCheese's picture should be corrected like this:

The key is average ppfd or total lumens or whatever.
It is lower when a diffuser is applied, if you measure the light intensity you'll see it dropping faster with distance compared to a naked cob or "point light source".
As I said before, canopy management and knowing your light is key to get the most out of the space.
Intersetingly, I use cobs and QBs and prefer cobs for my grows. The QB's have a higher output per watt but their LES(light emitting surface) is way too large for my taste, the light cone of cobs gets better through the canopy compared to QBs.

Cheers

 

[f-e]

The individual beam becomes lost when many LEDs are used to light up every point of the grow.

 

[SuperBadGrower]

f-e's is the correct analysis. IN essence it is a moot discussion. The only growers who have a non-diffuse light in 2022 are HPS growers with 1 light and outdoor growers who use the sun. Literally everybody else is on diffuse lights, whether they are bars, QBs, or even blurples or multi-cob fixtures from yesteryear.

(using multiple HPSes creates diffusivity in the sense that photons arrive at a similar point from multiple angles instead of only one... like big COBs... maybe those don't count )