[Wiggs Dannyboy]

Hey everybody,

I've been looking and searching for some specific info on how far LED light penetrates past the canopy down into the the lower bud/leaf areas.

This info exists for the other kinds of light used to grow weed...cfl's have about 10" of penetration before becoming somewhat useless for growing, the HID lamps have expected penetration listed depending on the size of the buld. But I can't seem to find any info on LED lights about penetration.

The closest I've come so far is the mention that if you keep the higher powered lights to close to the canopy you will bleach out your canopy. Some have said they must keep the light 16" above the canopy to avoid bleaching. This suggests to me that they must have pretty good penetration past the canopy, but some things...too many things, actually, end up being counter-intuitive.

Can somebody point me to an article or other information source that speaks to the degree of light penetration when using LED lights?

Thanks for any help you can provide.

LED's are definitely growing some good weed, that much of my research has shown for sure.

[Phychotron]

That's too broad of a question, different beam angles, secondary optics, power draw, spectrum, diodes used, etc.

each fixture uses a combination of these variables, so your better off looking at a light by light analysis.

https://www.youtube.com/watch?v=DAw13w9eFxY

[PaullyHighBred]

The reason there isnt a light penetration index for leds like hps/cfl/mh is because with leds we're dealing with more variables.

Which leds? Cree, Osram, Ledengin, Bridgelux, epistar ect.
What power are they being driven at? 1 watt, 3 watt, 10 watt ect.
What kind of optics? 60, 90, 120 degrees or no optics at all
How many Leds over how large an array?

Without optics using top binned leds I get about 12 inches of effective light penetration for flowering. Buds still form well below that but are fluffy and larfy.

With Carclo optics (80degree) on Cree XPG, XT-E, XP--E leds I get solid bud formation down about 18-24 inches from top of the canopy


hope this helps

-PHB

[Weezard]

Photons are photons.
EMR is EMR.
The ISL applies
But, lensing will surprise.

I find that a 90 - 60 degree lens give excellent "penetration"
with leds.
Add a good fan and shadows from upper leaves are no longer a factor.
My lights are rigged to move when the cooling fan cycles so I get good, hard buds all the way down.

"all the way down" = about 4 feet.

Aloha,
Weeze

[Wiggs Dannyboy]

Thanks everybody...looks like I need to dig a little bit deeper on the LED research.

[Amanita]

Good post Weezard.

[siddhartha]

A light mover with a high powered LED gives plenty of "penetration". As stated before, a photon is a photon, more photons in the right spectrum is "penetration". So if you get an LED that pulls 710 real watts, with a good spectrum you will see dense nugs deep down. My current Sour Kush grow the plants are stupid tall and have good nugs all the way down.
Sidd