how important is CRI

i was looking at cfl's and noticed different cri color rendering index i think
i see alot of 85 and what not but i found a buld that has a 6700k and a cri of 98 just wondering how important cri is and realy whats it for

color rendering index (cri ), Is really only usefull for people. It is how accurately the bulbs show color from the objects the light hits.

Daylight cri 100.

The higher the number the closer the colors appear to a natural sunlight condition.

Plants, however don't have eyes and the don't care what the light looks like as long as the correct wavelengths are there, cri is not important for them.

your plants will look nicer to you tho... with a higher cri!

cool i guess thats not a bad thing then as long as its producing the right color temp and such what do you think of these for veg the 2.0 version

Exo Terra : Products : Compact Fluorescent Bulbs

they should work just fine, i would save the money and go get a 6500k or 6400k daylight bulb at walmart or wherever, i imagine those reptile lights are expensive.
If you have some, use them and let us know They look like they have a pretty good intensity in the red spectrum area too as well as blue and some uv. But for veggin i see no problems with them. except maybe cost.

ive got a 2.0 and a 10.0 the 10.0 is a bit scarey in the uvb spectrum ill try the 2.0 on my seedlings and see what happens

You should avoid buying tubes if they do not have a CRI rating of at least 80%, as they may be cheap tubes intended for office buildings. These only use a single phosphor that leaves large gaps in the spectrum of light. They have a CRI as low as 50%, which tends to give people's skin a sickly look, and colors just don't look right. These give energy saver bulbs don't normally have a bad name, but are greatly out-performed by modern, fluorescents with a high CRI.

good point chronic, A higher cri and a newer bulb has a better spectrum spread generally.

High pressure sodium bulbs range from cri 22-35 or so (i think) and they seem to work just fine for flowering.

That's because hps lights emit thousands of more lumens than cfl's.

moreover hps has the correct spectrum for flowering, the point is cri does not matter to the plant.

Of course if your using a fucking hps the cri doesnt matter because the light is emitting anywhere from 45 to 120K lumens depending on the watts, but who gives a shit about hps, this is CFL GROWING. Not HPS GROWING. So go post that shit where it matters. Now when you talk about CFL lights that are emitting, 1,600 - 15,000 lumuns tops, then yes it does matter how well the light render's it's color....

alka said:

moreover hps has the correct spectrum for flowering, the point is cri does not matter to the plant.

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let's not get ahead of ourselves hotshot. "closer" would be a better choice than "correct".

ok, so sorry to mention hps in a thread cfl thread but seriously .. chill dude... i am only trying to help without splitting hairs...

i will go one step further then and say that for cfl's... CRI DOES NOT MATTER! a light can have a high cri but not have the spectrum we need for growing properly.

jeez...

on the last point.. ok "closer" to the correct spectrum. whatever makes you happy.

Lol it's all good dude, i was a bit harsh my bad. Im just tired of seeing cfl vs hid thread. We all know hid is the best way to grow plants but nobody cares.

Point is grow two female clones, one with lower CRI CFL than the other and i guarantee you will see the difference, fuck words, im going to do that just to prove to you it does. My plants are 7 days away from flowering under CFL's and im going to take clones flower each one under different CRI cfl's of the same wattage and we will see how much the CRI matters. You had better stay tuned to the thread in my signature if you want to see the action my friend.

hehe.. ok chronic you got me interested now... i hear what you are saying, and i know you know what kinds of lights to get from your thread. (I have read it btw, good job mate!)

Here's something that might get you thinking tho

Candle: 1700k 100 CRI
High Pressure Sodium: 2100k 25 CRI
Incandescent: 2700k 100 CRI
Tungsten Halogen: 3200k 95 CRI
*Solux Bulb: 4100k 98 CRI
Cool White: 4200k 62 CRI
*Ott-Lite™ Pro: 5000k 82 CRI
Clear Metal Halide: 5500k 60 CRI
*Verilux® "Natural Spectrum®": 5500k 82 CRI (also called HappyEyes® and Trucolite Phosphor Technology™)
Natural Sunlight: 5000-6000k 100 CRI
*BlueMax™: 5900k 96 CRI
Daylight Bulb: 6400k 80 CRI
*Sharper Image Bright as Day™ Lamp: 6400k 80 CRI (also called "wide-spectrum","daylight spectrum","natural spectrum")
*NextTen SunWhite® Lamp: 6400k 82 CRI
*Bell&Howell Sunlight Lamp: 6500k 80-85 CRI
*FirstStreet Balanced Spectrum®: 6500k 84 CRI

I would rather my cfls have as narrow a band as possible to what i want and not wast wattage on providing extra greens and blues so that it looks nicer.

All the lights above that have a high cri usually make terrible grow lights (with the exception of the sun).

I appreciate the opposing view tho, i will be checking your thread.

Right CRI increases as the Color Temperature increases. Why do you think that they call 5000-6500K full spectrum because it literally covers all spectrums. Which would mean it would render all colors. Thats why the CRI gets higher.


Dude i think you got me all wrong, Im not saying that you should ALWAYS aim for higher CRI, im just saying if you have two 2700K 42 Watt CFL's, one is 69% CRI and one is 85% CRI then go with the HIGHER CRI bulb.

In all reality you want to simulate nature inside your grow room and the color temperature of natural sunlight changes throughout the day. In the morning and at sunset, natural sunlight is in the 2,500 - 3000 degree K range. That is why the Grand Canyon and fall trees look so brilliant in morning and afternoon sun. Conversely, at high noon, normal sunlight is very near 6,000 degrees K .That is why evergreen trees and blue water look so good in brilliant full spectrum sunlight.

So in order to simulate that environment youll wan't to mix and match the spectrum's throughout the ENTIRE grow.

Any cfl thats 80%= or < is decent.

Dr.Chronic said:

Right CRI increases as the Color Temperature increases. Why do you think that they call 5000-6500K full spectrum because it literally covers all spectrums. Which would mean it would render all colors. Thats why the CRI gets higher.

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sigh.... read that chart a little closer.. cri has nothing to do with color temperature.

what they said