What specificly gives an HID lamp more penetration than an equivalant wattage CFL?

[Phaeton]

That inverse square only works bare bulb and point source.

Bare bulb: A board 1' away with 1" hole (.78 square inches) gets 1 watt total. A second board 2' away has a circle of light from the first hole. This circle of light is 2" across (3.14 square inches), 4 times the area. The 1 watt is still 1 watt, but spread over 4 times the area, 1/4 the intensity.

Reflector bulb: Depends on the reflector, but the focused light going through the 1" hole is not spreading the same. If the focus is over 2' then the light will get smaller by the second board and the intensity could multiply, hot spots they are called.

Large area emitters: A 2' circular light going through the 1" hole will make a 2' circle on the second board, still the same total watts as the 1" hole, 1/288 the intensity. The real world has infinite holes in the first board and the light falloff does not begin until an emitter diameter distance, 2' in the example. So what?

Reflectors & lights rim to rim: A 7' circle packed with overlapping +90 degree reflectors functions as a 7' diameter emitter with little to zero light falloff out to 7' from the lights.

What this means for penetration: The top of the plant is 3' from the 7' light, the bottom of the plant is 6' from the light. Instead of having 4 times the light, the photons per square inch of the upper leaves are no more than the photons per square inch of the lower leaves. Out to 7' the penetration equals the sun.
That was the hard part.

CFL lumens per watt are really close to standard HID. HPS puts out fully half again more light, nothing else comes close.

Yes, what isn't light is heat, CFL's spread this heat over a larger area, creating lower temperatures for identical heat loss wattages. Similar to lumen vs flux, it is measured differently.

 

[Phaeton]

I gotta start posting earlier, or stop posting late. Original question I first posted to address, forgot about it.

Yeah, why does equal lumen CFL have crappy penetration compared to HID?

That heat thing above. The temperature of the CFL is less, on the order of 1000 degrees (arc tube vs coil tube) less, I certainly put a cooler bulb a lot closer. Let's have a show of hands, how many put the CFL 12" or more from the plant?
Penetration is a multiplier, difference top to bottom of the plant vs the distance to the light source, regardless of brightness. A close light always has less penetration than a far one. The hard part is balancing penetration with intensity.

With a light 3" away, even at bleaching levels, the leaves 2' down are turning thin and colorless (still 1/8 light even with good reflector [LED]) from lack of light, that light would need repeated every 3" to be effective. Only leaves exactly in the sweet spot grow correctly, efficiency does not trickle down to the rest of the plant, the underlit parts have to be carried.

The implications of what's needed to work with this are horrid and best not thought about. That is the impression I get from locals I visit. MJ is almost impossible to kill and the top always smokes very well, thank you.
:kitty:

 

[Tony Aroma]

Actually it does. HID's produce more photons(aka light) per input watt than CFLs. Higher number of initial photons means a higher number of photons make it through the first layer of leaves(and the 2nd, and 3rd, etc), giving them deeper penetration.

I believe the question is: Same amount of light/photons from a CFL and HID -- why does HID penetrate better than CFL? You're answering the question: Do more photons penetrate further than less photons? The answer to that is yes regardless of the light source.

And "penetrate" doesn't refer to light going THROUGH leaves. Very little light of any intensity actually goes through leaves. Leaves are opaque and very good at absorbing light. That's their job. Penetration refers to light getting BETWEEN the leaves below the canopy.

 

[¿kama3]

It's all about spectrum darling ... A rainbow of colors

nicely said, more lumens means more spectrum to penetrate or absorb how the mr. likes to take this. of course i don't talk about the better crystal production that may come with improved blue spectrum in the warm white cfl nor even higher lumen outputs without the right spectrums from halogen or somewhere but we're all right here in that question

 

[¿kama3]

this is one smart plant, it takes the light from above and shares energy with it's lower nodes i think, i guess thats why the oldermen's say trees have their souls too!

 

[BasementBreeder]

Tony,

The OP states the question as this, "What about a 125w HID lamp allows it to penetrate the canopy better than a 125w CFL?"

The HID produces significantly more photons. End of story. That is the only reason it has greater penetration. I would be very surprised to learn that X umole/meter^2/sec from a CFL has significantly different penetration that the same quantity of light from a HID source.

My earlier post, when I wrote "through", I should have written "between". Thanks for pointing that out.

 

[Phaeton]

I try to use examples anyone can visualize, doesn't help some. Where did light going through leaves come from? WTF?

I do believe it came down to the same amount of photons coming out of the HID and the CFL was the latest way the question was formed. It is believed the CFL still has less penetration even with the same number of photons emitted from the bulbs.

Here is another easily done demo.
Incandescent light put out 1/8 the light of CFL or HID per watt, I hope that isn't controversial.

Get a 55 watt CFL at the local department store, now get a reflector, high bay polished would be good, but anything you want, price no object, design doesn't matter.
Go outside on a dark night in a driveway. Plug in the light and have someone walk away until they are hard to see.
Now turn on 1 one a car's 55 watt headlights, 1/8 the photons being emitted campared to the CFL in your hand pointed at the person at the end of the driveway.
Holy shit. The person could read a book by the light hitting him.
The big fuzzy CFL does not focus, the waste light is so great that even 8 times the photons will not light up the target as well as a puny little point light with focus.
It does not penetrate as well because less light makes it to the plant. The concept is simple and straighforward, the more light that hits the plant, the more light the plant can absorb. This is not rocket science. 1+1=2, every time..

There is some honest misunderstanding happening, but mostly not. To those who like to act plain stupid, hey, maybe it is not an act.

 

[mrwags]

Man you guys are talking like the Organic Folks To keep this simple so that us hill jacks can understand let's say the leaves are solar panels that through the day soak up energy from the lights. No light doesn't go through leaves (giggle giggle) but at night when the lights go out all that energy is sent down to the roots with all the days produced starch's and sugars and that where the magic happens.

A light mover is a good way to show you how moving the lights allows for the lights to hit the leaves as it moves back and forth. Just like the guy saying he used 10 4000's instead of 4 1000. His ability to get light to where otherwise he could not allowed for his new found growth and so others find the same damn thing by using a light mover myself included.

As far as different lights ONE word. SPECTRUM The ability to replicate the sun. You can grow MJ with a freakin flashlight if you change the battery's enough they just won't be those think plump buds your looking for done by those who keep it simple and use the right equipment for the job.


My Penny
Mr.Wags

 

[moonwalker]

Condence cfl lighting element into the size of hid and you'll get similar penetration out of it. Thats what high intensity means. Cfl's are just as efficient as hid's but their intencity is lower hence the spread. How many u-turns on cfl 125? Whats the total area of lighting element? Compare with hid. Both can yield similar weights but spread/intensity must be taken into account determening grow style (trees or sog etc)

 

[ganzuul]

If I remember the sciency bits right, lumen is measured at 555nm, which is green light at the wavelength the eye is most sensitive to. As growers we don't want green light since plants are green, meaning they don't absorb but rather reflect that light. Under a good LED grow lamp the plants should appear black since all other radiation is absorbed.

I made this image manipulation to illustrate that:

I inverted the colour of the image and then enhanced the reds to make it look like a LED lamp for flowering while preserving the hues. A lot of the blue on the upper image to the right is lamp power which won't get absorbed. Essentially it is wasted.

To me, penetration means how far down into the canopy the light reaches while still providing the reds and blues. I think the most effective way to achieve this is with more lights and mylar on the walls. The way to experience what the plant 'feels' in these light is to make goggles with a white ping-pong ball cut in half and look at the light sources. - This is how a lumen meter works, but only in principle at 555lm while your eyes see the entire rainbow spectrum.

 

[knna]

Penetration itself depends of more factors than just the lighting used.

So I answer to the question of why a HID emits with far higher intensity than a CFL of equal wattage.

Two reason for that. One has been already noted, HIDs are more efficient, emits more light for each watt burned, whatever in lumens or photons or PAR watts you measure light.

The other is the light emitting area size. Very small for a HID, which is not all the bulb, but just the discharge arc. From some mm to some cm, in general no more than 1" long and linear. Very large for a CFL, where the light emiting area is all the surface of the tubes. This reason account for the largest part of the difference in intensity between HIDs and CFLs.

 

[nukklehead]

Does depth of penetration really matter? Is there anything to be said for modest penetration?

Thats what I keep trying to convince my ole lady but she still says no

Good discussion

 

[Phaeton]

I purchased color meters for setting up my grow. Hundreds of dollars each for red, blue, UVB, and PAR. Whoa, no green meter?
The green is covered by a $40 lumen meter, as mentioned in a previous post, lumens are green/yellow.

I also aquired some 60 degree beam LED lights. The penetration with them is close to double the HID system they replaced.

I'm giving the comparison in umols of PAR from the top of the plant to the lowest branch I get bud from. Roughly 26" on average.

9 X 400 w HID, 1000 on top, 400 on bottom. 10" to 12" from lights, lights are rim to rim with 23" reflectors.

5 x 460 w LED, 1000 on top, 700 on bottom. 14" to 16" from lights, light does not overlap.

Measuring the output, a 120 degree beam has 4x the light falloff as a 60 degree beam, this makes all the difference that can be.

 

[whazzup]

there is a lot to be said though for overlapping lamps, specifically if you consider crop penetration and uniformity. The inverse square law you can forget with CFL: it applies at a distance about 5 times the length of the light source. Even for a HID lamp that can be as far as 3'.

 

[yoss33]

you do know HID stands for High Intensity Discharge right?
HID's (HPS specifically) have have a high LPW (Lumen Per Watt) rating, so you get alot more lumens out of your HID than your CFL for every watt you put in. lumens are a measurement of visible light intensity(i.e. penetration power), not the amount of light. lumens do not add, so 2 bulbs that are casting off 90,000 lumens right next to each other still only add up to 90,000 lumens. so basically the hid's are brighter, duh.

to be honest, photosynthetic activity of specific light nm wl (nanometer wavelenght) also comes into play with "canopy penetration" but not so much with your question. the benefit of CFL is lack of heat, so a CFL can be placed closer to the canopy, thereby increasing its efficiency.

Hi man,
I think you have the idea about lumens wrong. Lumen is the unit of luminous flux, which IS the amount of light, but only the amount visible to the human eye. Two lamps of 1000lm each, DO have a total output of 2000lm, as their luminous flux is additive.
I think you mistake lumens for candelas - candela being the unit of luminous intensity. Or maybe you mean luminous emittance, measured in lux (i.e. lumens/m2), which is still different than lumens. Whatever you mean by "brightness", it's either cd/m2, or lm/m2, but NOT lumens.

 

[T_B_M]

I understand lumens PAR etc., that isn't my question. My question is why does light from an HID lamp (be it MH or HPS) travel further (therefore penetrating better) than CFL light of equivalent wattage? Or if you guys prefer why do HID's penetrate better than CFL even if lumens or par ratings are equal? To be clear i'm not arguing for or against using either, i am simplily curious as to how the mechanics of the bulbs differ to produce greater penetration.


For the record lumens are terrible way to measure a bulbs worth for growing plants.

Lumens are a decent indication as to what you are giving the plant though. Getting the PAR rating is near impossible unless you spend the money on equipment to measure it. So your point on lumens is moot since all the manufacturer gives us is lm rating. Terrible is the wrong word there.

Sodium, mercury, and whatever else is in the HPS emits brighter and stronger than CFL. Wikipedia could have told you this....

150W is just the input wattage, the lamp takes that and converts it to light. Some lamps just do this better than others. But the drawback is more heat introduced the brighter the light gets. The photon density and radiation is greater in HPS.

 

[machine77]

Tbh i don't think anyone has answered the question and i don't want to be insulting anyone but all the answers are really more questions everyone has put forward lumens par watts etc but the answer lies in the design of each light the cfl produces light by exciting gases with a small electrical discharge where as an hid produces light with a high temperature arc it basically burns light thowing of huge amounts of photons but using up lots of energy in production of light by drawing up energy in greater amps ie using more current you cannot compare 250w cfl light against 250w hids you can only compare like for like ie 250w cfl vs 250w cfl they are essentially completely different animals due to the high operating temps of hids the photons have greater weight and therefore more energy and as with anything in nature that with more weight travels further than that with less when leaving source at same speed the light from the cfl does not have the same operating temp as an hid but uses less energy when doing so that is the energy saving part but the hid is the most effecient light form an engineering point of view as it produces the most light with the greater energy but uses more electrcity to produce it a 250w cfl is a 250w cfl due to the design of the light it physically cannot produce the the amount of photons that an hid does e=mc2 ie energy is equal mass multiplied by the speed of light squared a photon from an hid has more mass therefore more energy and can exicite the cells of ther plant deeper into canopy

 

[rives]

I gave up about half way through. Please use some punctuation.

 

[Hydro-Soil]

Penetration itself depends of more factors than just the lighting used.

So I answer to the question of why a HID emits with far higher intensity than a CFL of equal wattage.

Two reason for that. One has been already noted, HIDs are more efficient, emits more light for each watt burned, whatever in lumens or photons or PAR watts you measure light.

The other is the light emitting area size. Very small for a HID, which is not all the bulb, but just the discharge arc. From some mm to some cm, in general no more than 1" long and linear. Very large for a CFL, where the light emiting area is all the surface of the tubes. This reason account for the largest part of the difference in intensity between HIDs and CFLs.

And Knna, the light guru, pegs it again. Thank you Knna Good to see you around.

Stay Safe!

Yes, the question has been answered. Edit: To put it in layman's terms, Same garden hose, same water pressure (wattage)... but the small nozzle has a very strong stream and the shower head fitting has a gentle flow.... both have the same amount of water coming out.

 

[Iraganji]