How far to keep your LED's / Quantum Boards from the canopy?

hybridway2

Amare Shill
The fundamental key to using tightly clustered, high powered
, HE, Qb's is Diffusion. Just like the laws of a greenhouse. I know this because I've tried it sbs. Light losses are minimal while plant health & yields are major. 70% frosted has shown up to a 30% increase in yields in most crops, including tomatoes.
I personally am building a suspended, pixilated, diffusion cover (cheep HomeDepot) made for a drop ceiling.
The qb 96's were what I used for my small test.
Aside from that, 28"-36" In flower for your standard 550 or 600 HLG, QB.
 

Blossom21

Active Member
Sorry lol ,
I'll mess around with my lights and see how the leaves respond, so far so good but i'm sure they want more light :cool: It's been a while when i saw the leaves reach for the light like that, but i wasn't sure if that would be a good or bad thing at later flowering so i stopped paying attention to them a long while ago.
The fundamental key to using tightly clustered, high powered
, HE, Qb's is Diffusion. Just like the laws of a greenhouse. I know this because I've tried it sbs. Light losses are minimal while plant health & yields are major. 70% frosted has shown up to a 30% increase in yields in most crops, including tomatoes.
I personally am building a suspended, pixilated, diffusion cover (cheep HomeDepot) made for a drop ceiling.
The qb 96's were what I used for my small test.
Aside from that, 28"-36" In flower for your standard 550 or 600 HLG, QB.
Sorry i don't understand some of the shortened words and things like "70% frosted", i'm not familiar yet with all the growing terms and other words people use here so bear with me. English isn't my first language either, so making things little easier to understand would be nice.

I just have my 4 boards fairly balanced around the 4x4 tent, both drivers turned to max i get around 520W's of power when i tuned and measured them with a multimeter. 28"-36" seems a little high when i'm averaging 15" per board (and turned at 80% power) at the moment, not the mention my buddy who keeps his 240w board (same lights, just a different driver and 288pcs x2 of lm301b's in one long heatsink/board) even closer from the tops with full power. Any thoughts?
 
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hybridway2

Amare Shill
I'll mess around with my lights and see how the leaves respond, so far so good but i'm sure they want more light :cool: It's been a while when i saw the leaves reach for the light like that, but i wasn't sure if that would be a good or bad thing at later flowering so i stopped paying attention to them a long while ago.

Sorry i don't understand some of the shortened words and things like "70% frosted", i'm not familiar yet with all the growing terms and other words people use here so bear with me. English isn't my first language either, so making things little easier to understand would be nice.

I just have my 4 boards fairly balanced around the 4x4 tent, both drivers turned to max i get around 520W's of power when i tuned and measured them with a multimeter. 28"-36" seems a little high when i'm averaging 15" per board (and turned at 80% power) at the moment, not the mention my buddy who keeps his 240w board (same lights, just a different driver and 288pcs x2 of lm301b's in one long heatsink/board) even closer from the tops with full power. Any thoughts?
Oh, I see, my bad. If you have x4 ,288 boards evenly spread through out your 4x4 then 18"-24" is optimal.
I've seen charts using x4 boards in that array & for the most even coverage or ppfd it was somewhere between those 2, 18-24". Gives like a 950 ppfd at 550w i think. Don't quote me on that. Will see if I can find the charts.
Diffusion applies to some with limited hight or the standard x4, 288 boards on one fixture per HLG Sizing.
 

Blossom21

Active Member
Oh, I see, my bad. If you have x4 ,288 boards evenly spread through out your 4x4 then 18"-24" is optimal.
I've seen charts using x4 boards in that array & for the most even coverage or ppfd it was somewhere between those 2, 18-24". Gives like a 950 ppfd at 550w i think. Don't quote me on that. Will see if I can find the charts.
Diffusion applies to some with limited hight or the standard x4, 288 boards on one fixture per HLG Sizing.
Would be nice to see the charts if you can find them, where to look at if i try to search for 'em too?

And btw what did you mean by the 70% frosted comment if i may ask that too.
 

MoroccanRoll

Well-Known Member
The fundamental key to using tightly clustered, high powered
, HE, Qb's is Diffusion. Just like the laws of a greenhouse. I know this because I've tried it sbs. Light losses are minimal while plant health & yields are major. 70% frosted has shown up to a 30% increase in yields in most crops, including tomatoes.
I personally am building a suspended, pixilated, diffusion cover (cheep HomeDepot) made for a drop ceiling.
The qb 96's were what I used for my small test.
Aside from that, 28"-36" In flower for your standard 550 or 600 HLG, QB.
Diffusion is an excellent idea however you'd be better off with one of the clear prismatic lenses from your home improvement store. The frosted lenses use opaque pigment which will reflect or absorb incident light instead of transmitting it. Your losses will be a lot greater than you expect. I used to design camera and LED flash lenses which required transimissivity in excess of 98%. Even with optical glass that's not an easy task. Are you okay with 20%-30% losses?
 

hybridway2

Amare Shill
Diffusion is an excellent idea however you'd be better off with one of the clear prismatic lenses from your home improvement store. The frosted lenses use opaque pigment which will reflect or absorb incident light instead of transmitting it. Your losses will be a lot greater than you expect. I used to design camera and LED flash lenses which required transimissivity in excess of 98%. Even with optical glass that's not an easy task. Are you okay with 20%-30% losses?
70% is only 5-7% over a clear cover which is 3-6% over bare, laser diodes.
Bought the clear Prizmatic from HomeDepot though.
So a 9-11% light loss in exchange for fully engulffed lit plants that are happy, not as sensitive to hight restrictions & up to a 30% higher yield. Ill have it.
 
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MoroccanRoll

Well-Known Member
Good call. Diffusion films have the advantage of improving uniformity of illumination or illuminance. That's where you're getting your improvements.
 

FakePres

Member
All help is welcome of course, but i'm sure how cannabis reacts to light has been studied already pretty well, so for example someone could maybe hit me up with some good links or videos that i could/should watch, i would appreciate.
There are some pretty good videos and great cannabis growing info from Dr Bruce Bugbee at Utah State University where they have a license and lab to study cannabis. I believe one of his vids addresses light requirements/spectrum vis-a-vis Mary Jane. I've seen these same YouTube vids referenced here on the forum as well. Give em a view, I'm sure they'll be of help to you. Happy Growin' ;)
 
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Blossom21

Active Member
There are some pretty good videos and great cannabis growing info from Dr Bruce Bugbee at Utah State University where they have a license and lab to study cannabis. I believe one of his vids addresses light requirements/spectrum vis-a-vis Mary Jane. I've seen these same YouTube vids referenced here on the forum as well. Give em a view, I'm sure they'll be of help to you. Happy Growin' ;)
You can edit your post and delete the last one so there's no damage done or extra space wasted, just a tip :eyesmoke:. Also thanks for the recommendation, will definitely go check out the videos!
 

hybridway2

Amare Shill
Good call. Diffusion films have the advantage of improving uniformity of illumination or illuminance. That's where you're getting your improvements.
I've posted several studies proving that diffusion is the key to using QB's (tightly knit), COBs, Pucks & almost all led. When diodes are ran soft & are spread FAR apart, the diffusion isn't really needed.
It's funny cuz the China Copy-Cat designs are basically making these Much needed improvements before the Pemium Led Horticultural companies whom are more concerned with umol/j. Same goes for spectrum.
My buddy linked me this
 

Blossom21

Active Member
I've posted several studies proving that diffusion is the key to using QB's (tightly knit), COBs, Pucks & almost all led. When diodes are ran soft & are spread FAR apart, the diffusion isn't really needed.
It's funny cuz the China Copy-Cat designs are basically making these Much needed improvements before the Pemium Led Horticultural companies whom are more concerned with umol/j. Same goes for spectrum.
My buddy linked me this
BRB going to tape some baking paper under the QB's :D. But really would that work, or has anyone even tested different materials on LED's and how well they work in comparison? I'm now wondering what material i should get and how to attach them/it to the board (without fire hazard and how close the material should be for maximum effect). So many things are starting to make sense to me now!
 

MoroccanRoll

Well-Known Member
BRB going to tape some baking paper under the QB's :D. But really would that work, or has anyone even tested different materials on LED's and how well they work in comparison? I'm now wondering what material i should get and how to attach them/it to the board (without fire hazard and how close the material should be for maximum effect). So many things are starting to make sense to me now!
This would not work. The purpose of a diffusion film is to scatter light in multiple different directions. This reduces the shadowing effect of leaves. Great for a greenhouse where solar radiation arrives from a single direction (the sun). Some light passes through and is scattered by the diffusion film however the film also absorbs light (and converts it to heat) and reflects light (back toward the sun or the LEDs). The net effect of using a diffusion film with a quantum board style led array would be to decrease the amount of light actually reaching your plants. Quantum boards and other LED arrays are an attempt to simulate a planar source of radiation where every point an equal distance from the board has roughly the same illuminance. If you're curious, you can google point source, line source, and plane source of radiation for more information.
 

ComfortCreator

Well-Known Member
Not sure why there hasn't been mention (besides the OP) of a decent light meter.

Dr. Meter, about $30, is all you need.

Imo you are right to be curious but ask the wrong question. I would ask, what is the optimal amount of light for a plant?

Your question is tactical...how do I, vs strategic...why should I

There is an optimal spectrum and intensity for lighting. It varies based upon many factors, but the general ranges are well specified.

Now lets say you know the optimal range. Can you use it, with your setup? If your setup allowed you to be at 18" vs 12", which would you choose? Why? Now if you had to be at 12" to be optimal and it burns your plants, which is more important...max lighting or the highest quality product?

What grow method do you use? Are they growing naturally or trained? As mentioned in earlier posts, there is intensity, and there is spread.

There is no need for additional diffusers with QBs. They diffuse well especially at recommended heights.

Your friend gets no points for how close he runs his lights...only for having a great product. See my point?

Get a meter. Dont guess.
 
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