It's both reflectivity and dispersion. You're entirely correct about loss of intensity, and it drops off quickly, just not as fast as you'd think. My calculations showed that headroom under a dispersed source is roughly equal to the productive canopy depth. If the top of the canopy gets 1000-1200 umols, then at twice the depth it should get about 500 umols which is the low end if the productive range.

So if you have one foot of headroom and the top is 1200 umols, a foot deep into the canopy it's down to 500. If you want a deep canopy you need deep headroom.

Kinda counter-intuitive. :hmmmm:

:cheesygrinsmiley:

OK...this is very counter-intuitive and not sure I understand. :hmmmm:

Let's use your example:

So if you have one foot of headroom and the top is 1200 umols, a foot deep into the canopy it's down to 500. If you want a deep canopy you need deep headroom.

Are you saying if you raised the light to two feet above the canopy you'd get two feet of productive depth into the canopy and if you raised the light to four feet above the canopy you'd be productive four feet down into the canopy??? o_O

Surely, as you're raising the light the umols are decreasing at both the top and as you penetrate into the canopy. I don't see how you can be more productive deeper into the canopy with the lights farther away.

What am I missing??? :hmmmm:
 
What I didn't point out is that if you increase headroom, you'll need more power. :cheesygrinsmiley:

But my point is that if you're satisfied with the intensity at the top of your canopy, and you're running at a foot of headroom, you don't have much productive canopy depth. (not you specifically - just an example).

When I ran lights with less intensity, I had my plants closer to the lights. But I got a lot of airy swag below a foot. Now I have more than enough light and run 2 feet of headroom. That gave me another foot of canopy depth and increased my harvest by 30%+.

The top of the canopy can only take so much intensity without cooking and that's 1000-1200 umols, and the bottom needs 500 umols or more, and twice the distance is roughly 1/2 the intensity. Canopy depth grows as you move the light source away (and increase power to compensate). A foot of headroom is not a good thing to have.

So the instinct should be to find ways to increase headroom while still getting enough intensity to the plant, ie dispersion, spread, reflection, etc. We're dumping all those photons into the space to rattle around. We want to use them efficiently, and that's not always to concentrate them into a smaller area.

:bongrip:
 
Ya, but that's single source.

Multi-LED panels are a lot different than the 6 inch bar on a HID lamp. Unless the HID moves, a lot of the leaf surface will never see direct light. With a wide spread of LEDs across the sky, far more leaf gets direct exposure to the light source. Intensity is spread throughout the plant canopy.
 
OK...this is very counter-intuitive and not sure I understand. :hmmmm:

Let's use your example:



Are you saying if you raised the light to two feet above the canopy you'd get two feet of productive depth into the canopy and if you raised the light to four feet above the canopy you'd be productive four feet down into the canopy??? o_O

Surely, as you're raising the light the umols are decreasing at both the top and as you penetrate into the canopy. I don't see how you can be more productive deeper into the canopy with the lights farther away.

What am I missing??? :hmmmm:
Your not missing anything Krip, especially if you believe no matter what lighting it is, the above pics rules will apply..footprint will just change and intensity with distance...
you arw correct.
 
I guess as you raise the light the readings at the edge of the tent would go up....to a certain point, and then they would start to read less there as well. Would that be the sweet spot for a given grow space.? The point where the edge of the space received the maximum amount of light?

Usually it loses about 10% - 20% each bounce. In a reflective tent it can be as low as 5%. The reason it doesn't appear as bright at the tent wall is that the walls usually don't see the maximum power of the fixture, and they are textured, reflecting the light in many directions. At 45° off center most LEDs emit 70% at an equal distance. At 60° the light is down to 50%, and at 90° off center there is no light.
 
What I didn't point out is that if you increase headroom, you'll need more power. :cheesygrinsmiley:
OK! Well, that's a pretty major thing to leave out! :rofl:

You have the ability to really dial up the power with your QB setup. Most lights don't have that capability.

With the XL1000, I can dial power up/down, at least up to 630 w, or so. The secondary lenses on the XL1000 also really help increase the canopy penetration.
 
PAR & PPFD INFO ON THE XL1000

Here is the PAR & PPFD info on the XL1000. Note that the readings are taken at 36" above the canopy:

Kind LED Grow Lights PPFD readings

PAR: Photosynthetically Active Radiation
PAR measures the total energy within the spectral light range from 400-700nm (nanometers) at which photosynthetic organisms are able to use light energy for the process of photosynthesis.

PPFD: (Photosynthetic Photon Flux Dentisy)
PPFD measures the actual number of photons contained within PAR that are actually reaching your plant's surface.

Why PPFD Matters
Since photosynthetic receptors in plants are activated by the photon itself, not the energy contained within that photon, PPFD is the best way to evaluate how well a grow light will perform and has become the most popular method for comparing indoor grow lights. Higher PPFD readings facilitate better, faster growth, and deeper canopy penetration.

kindparppfd.jpg

kindppfd.jpg

Results
In a side-by-side comparison with the industry's top grow lights, Kind LED came out on top, scoring both the highest overall PPFD reading (720.25) and the highest PPFD average (531.07).

Conclusion
Kind LED has a perfect tunable spectrum including both Infrared and UV diodes. IR and UV are not contained within a PPFD reading as they fall outside of the 400-700nm range, however plants have a significant non-photosynthetic response to these wavelengths that promote heightened oil and crystal development, producing superior quality harvests and greatly improving the flavor profile.

This most recent test demonstrates how KIND provides faster growth, better root development, greater quality harvests, and more efficiency. Secondary optical lenses increase canopy penetration by up to 200%. This, matched with a spectrum that gives plants exactly what they need at each wavelength over the photosynthetic spectrum at an unmatched intensity, is the reason Kind LED Grow Lights test better than any other light on the market.

Happy Harvests!

K
 
Mornin Krip......tell me...why can't u just turn the light up to full power , leave the settings ,timers and the 'fluff' alone and put it as high in the tent as u can.... done....finished.....no more messin with it......unless of course u like playing with it.
IMO......and its just mine.....all that extra 'fluff' the light has is really NOT needed and is a waste of resources and money that could have been used better elsewhere ......like higher quality parts/diodes.
With Budmaster2 ...their now old tech with their GOD series of lights ......They recomend putting them as high in the tent/grow space as possible.
This is because of very high quality diodes and drivers.
These lights are also 4 years old now......when Budmaster/Cropmaster release their new line of Pro lights they will shake up the world. . . Their technology is far superior to most other manufacturers.
They have even figured out how to completely remove 'bleaching ' too.....cheers.
 
Mornin Krip......tell me...why can't u just turn the light up to full power , leave the settings ,timers and the 'fluff' alone and put it as high in the tent as u can.... done....finished.....no more messin with it......unless of course u like playing with it.
IMO......and its just mine.....all that extra 'fluff' the light has is really NOT needed and is a waste of resources and money that could have been used better elsewhere ......like higher quality parts/diodes.
With Budmaster2 ...their now old tech with their GOD series of lights ......They recomend putting them as high in the tent/grow space as possible.
This is because of very high quality diodes and drivers.
These lights are also 4 years old now......when Budmaster/Cropmaster release their new line of Pro lights they will shake up the world. . . Their technology is far superior to most other manufacturers.
They have even figured out how to completely remove 'bleaching ' too.....cheers.
I COULD do exactly that. However, if I have the light closer to the plants, I they get the same PPFD at lower power, or more PPFD at the same power.

You can see by the PPFD chart posted, at 3' above the canopy, directly under the light gets 720 umols. I'd rather get closer to something like 1,000 - 1,200 umols at the top of the canopy and by keeping the lights closer to the plants, I can do exactly that.

The real advantage of the adjustable power settings, IMHO, is during veg when you don't need to run the lights at full intensity and, when the plants are small, you can get the light very close to the plants and cover all the area needed. So, there's some great power savings in veg for those that want to take advantage of it.

In flower, I'm a BIG believer in getting the most light possible to the plants, so I'll be running all channels at full power throughout just about all of the flowering phase, although I'll likely dial down the blues in the last couple of weeks. So, once again, the closest I can get the lights to the plants without the plants complaining, the better, IMHO.
 
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