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

[Mister_D]

Been helping a fellow grower that uses CFL lighting and it got me thinking. What about a 125w HID lamp allows it to penetrate the canopy better than a 125w CFL?

 

[dizzlekush]

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.

 

[LittleAmsterdam]

Lumens ! HID, HPS, MH all put out a lot more lumens then CFL, T5, or T8

 

[BigDawg]

i've read that plants don't receive lumens or something..

 

[187020]

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

 

[187020]

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

 

[dizzlekush]

plants receive alot of the light that is measured in lumens. lumens are not an accurate way to tell how much light your plants are getting. PAR (photosynthetically active radiation) ratings or reading are the best way to tell how much usable light your plants are receiving.

 

[LittleAmsterdam]

Lumens is a measurement of how much light a build will put out.

 

[Mister_D]

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.

 

[HempHut]

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.

HID's deliver "more light per watt," for simplicity sake.

Inverse square law kicks the amount of light available in the balls the further distance you move away from the light source.

Therefore, if you begin with "more light" by using a HID you can go further away from the light source (penetrate) and still maintain decent light levels than if you began with "less light" (a CFL).

 

[LittleAmsterdam]

Two bulbs with the same wattage can give off different lumens i.e. 250watt HPS would give off more lumens than 250watts of CFL

Same wattage but one bulb is preferred because it gives off more lumens.

 

[LittleAmsterdam]

"why does light from an HID lamp travel further than CFL light of equivalent wattage? "

Lumens !

 

[Mister_D]

Ok finally clicked for me. I feel completely retarded now that has sunk in. Must be smoking too much lately....... anyway thanks guys I was having a serious brain fuck for a minute there.

 

[LittleAmsterdam]

I / we've all made a fuck up or two learning this stuff. It doesn't come easy.....

I'm glad you turned the light on and saw the difference

 

[Mister_D]

I knew the answer already, just wasn't clicking for some reason. Like I said serious brain fuck for minute there.....

 

[Tony Aroma]

I believe it mostly has to do with an HID bulb being closer to a point source, as compared to a CFL which spreads the light source out over a larger area. Two identical lights putting out the same amount of light energy, the one with the smaller surface area will have better penetration because of less spread. Inverse square law explains this.

HID putting out more light (lumens or PAR or whatever) per input watt than CFL explains why they are more efficient. Or brighter. Not why they have better penetration.

 

[BasementBreeder]

I believe it mostly has to do with an HID bulb being closer to a point source, as compared to a CFL which spreads the light source out over a larger area. Two identical lights putting out the same amount of light energy, the one with the smaller surface area will have better penetration because of less spread. Inverse square law explains this.

HID putting out more light (lumens or PAR or whatever) per input watt than CFL explains why they are more efficient. Or brighter. Not why they have better penetration.

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.

 

[Nyfiss]

So what's the answer here? More energy of light in the right spectra with a HID?
Where does the rest of the energy go with a CFL? Heat, or light with a non/less-usable wavelenght?

 

[grow101]

A photon of a specific wavelength (e.g. 660nm) has always the same energy, regardless of it's source, the energy is what makes it's wavelength. Penetration on the other hand comes from more photons. Roughly: more lumen per watt equals more photons per watt, just so you can compare what vendors usually publish about their products.

PPFD (or short PDF, in µmol/m²s) is the right measurement for light in plant research and horticulture. You get those values for Philips GreenPower and Osram Plantastar HID lamps and maybe more vendors.

 

[Phaeton]

I use 10 x 400w instead of 4 x 1000, it isn't any brighter but has way more penetration, feeds the leaves from ten different directions, allowing more hits. Also allows overlapping spectrums, but not in this thread.