CFL penetration power

I've seen charts for HID-lamps that show how much foilage the light penetrates.

I would like the same for CLF's and T5's, because it's important information when dialing in your grow.
Can anyone point me in the correct direction please?

Also, WHY does CFL penetrate so little, it can't be as simple as lumens - or is it?
 

mipainpatient

Active Member
My understanding is that the INTENSITY (sheer lumen output) is what drives the HPS penetration. That and the fact that the wavelengths of light which are the largest spectrum output match some of the most reflected light (off of the canopy itself): Yellow and Green
So shoot tons of yellow and green at plant leaves and it will easily bounce around to the others. This is great if you are growing strains (including hybrids) which are adapted to higher ratios of green/yellow.
Intensity goes up with the wattage of the HPS, as your efficiency goes up, maxing at the 1000W afaik, off the top of my head I think i've seen like 160 lumens/watt---great return.
CFL is less intense, and a different spectrum of light, depending on the phosphor blend (2700K etc are approximates of the output)

That help?
MPP
 

mipainpatient

Active Member
An addendum:
since lumens are a measure of visible light ("visible" to humans has an efficiency peak in the yellow/green) yes it is all about lumens/watt for "penetration". However methods like SOG and SCROG which try to focus the growers attention at the very top of the canopy often are accompanied by defoliation practices to ensure ventilation of the canopy which end up ridding you of your popcorn anyways. (both work great for t5/cfl)
as for the penetration of the fluorescents, you want to look at their spectral output
the more green/yellow---the more penetration
However, the more Red/Blue---the more photosynthetically useful energy there is, so it is a tradeoff. My advice is to invest in a reflection strategy, or--with CFLS just keep the reflective surfaces close as hell
again, hope this helps too
MPP
 
Thanks.

A friend growing with HPS knows exactly how many inches the bulb is effective for, so he can make the most out of his vertical setup.
I want to do the same with CFL, I guess I'll have to experiment.
 

mipainpatient

Active Member
Check this, friend:
Take a test plant, and two 26w CFLs, one at the exact same height, equal distance from each other---maybe start with 4" just for kicks, at a height slightly above the top of the plant. After two weeks or adequate time for the plant to grow so the top is in between the bulbs, move one of them away or closer, but the other has to stay still. If the plant turns/reacts to the closer bulb substantially, Id say put your bulbs closer---up until the point you see leaf burn. In cold enough grows you pretty much need the leaf to touch the bulb to burn, if its warmer you might want to stay at 1/2" but that requires constant moving as the plant grows towards the bulb. You can avoid this by using low K bulbs for the lower canopy as they should be closer to the normal light types coming through the canopy and the plants shouldn't stretch to them as much as the 6500K or thereabouts bulbs.
peace,
mpp

p.s. if you try the test, you may see stronger leaning/stretching results if the two bulbs are slightly away from the plant in the first place, causing it to stretch in a slight angle deviating from "straight up"
I say this because the lower available light should cause the plant to show the phototropic (plant light-seeking growth-based movement) effects more
 
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