HID vs CFL

[Hagbard Celiene]

directly from http://en.wikipedia.org/wiki/Photosy...tive_radiation

PAR measurement is used in agriculture, forestry and oceanography. One of the requirements for productive farmland is adequate PAR, so PAR is used to evaluate agricultural investment potential.

The expression Photosynthetically Active Radiation, often abbreviated PAR, designates the spectral range of solar light from 400 to 700 nanometers that is useful to terrestrial plants in the process of photosynthesis.

don't tell me about what is important, you don't even seem to know that light IS radiation.

[JackdaWack]

Well you seem to be the expert enlighten me, lights is not defined by radiation either, uv rays are radation, and our ozone stops i belive 98% of that radiation. so if you can get skin cancer from 2% of the uv light that makes it to earth, im sure that any one who makes and distributes lights knows what leveles to use. Your talking about radiation that in the buisness world is taken very seriously and is of standards on all lights. nanometers in Par calculates for the difrent kinds of light that you can and cannot see, such as infrared. this can be understood in simpler terms as light color. So to answer your question you wold be looking for 550 to 700nm PAR (Red Spectrum).

[JackdaWack]

Your question is just what is light. the PAR level stands for the range of wave. In the 400 to 700 range it is visible light, if it were another it could be a microwave, radio wave, x-ray..etc.

[JackdaWack]

So you would think that every bulb you buy is going to be between 400 to 700nm, becuase anything else will not even be light. So it is irrelavent like i stated. if your question is what color light, then for veg. you want to use an even amount from 400 to 700nm covers all ranges of visible light, and then 550 to 700 for flower. cfl's reffer it as cool light and warm light, hps- red light and mh-blue light

[Hagbard Celiene]

actually, seeing as how floruo's use MV to create UV radiation, which exites phosphorus on the inside of the glass, which in turn creates usable light, i doubt if all of the radiation is given off as visible light. the visible light spectrum is what is used to guage Lumens, where as the light spctrum that a plant 'sees' is different from what a human sees, which is why there is a difference between lumens and PAR.

[JackdaWack]

Par is the specrum level of white/visible light. Lumens is a measure of the perceived power of light. So Fluorecent lights do use UV but it is not emitted. It is absorbed and turned into visible light, which can then be stated to be PAR which is visible light, there the same thing. They dont emit radiation. Obviously lumens and par are different. And yes plants do use the same visible light we see. I can see my light bulb turn on and off. And clearly see it is in the red spectrum(550-700nm) in the PAR range. and 400wtts tells me it has about 30,000 lumens. No radiation is emmited in hps becuase they produce only visible light. the source power refers to the ammount of lumens.

[Hagbard Celiene]

violet 380â??450 nm
blue 450â??495 nm
green 495â??570 nm
yellow 570â??590 nm
orange 590â??620 nm
red 620â??750 nm

obviously, if PAR is between 400-700, lumens wouls not be an exact representation of the plant useable radiation a plant can use. and PAR is exppressed in a value, its actually PAR lumens...

[4x5]

Use those cfls in your house to offset the cost of growing with hids. wiring up 20 cfls will cost more in power bars and sockets than the 2 hid's I'm using now, cfls require constant adjustment when growing, sometimes they fall over into your plants, also adjusting 20 cfls takes hours per week; lifting my hood takes 12 seconds.
"Anyone who tells you cfls don't work is an idiot, anyone who compares cfls to hid's is a fool"

[JackdaWack]

i dunno man this kid just wont listen to what any one is saying. lumens are a measure of the perceived power of light, that is its god damn deffinition. Stop trying to be technical. PAR is a freakin term some jack ass wanted to invent all it stands for is the visible light. PAr is not expressed in a value. it is a value it exactly whaT U SAID IT WAS. 400-700. What is the problem here. Every thing this kid says contradicts the last.

[JackdaWack]

stop reading shit off google and thinking your going to understand it.