Finding my Kelvin Temperature?

From link in earlier post

http://extension.oregonstate.edu/mg/botany/light.html

Light quality refers to the color (wavelength) of light. Sunlight supplies the complete range of wavelengths and can be broken up by a prism into bands of red, orange, yellow, green, blue, indigo, and violet.

Blue and red light, which plants absorb, have the greatest effect on plant growth. Blue light is responsible primarily for vegetative (leaf) growth. Red light, when combined with blue light, encourages flowering. Plants look green to us because they reflect, rather than absorb, green light.

Knowing which light source to use is important for manipulating plant growth. For example, fluorescent (cool white) light is high in the blue wavelength. It encourages leafy growth and is excellent for starting seedlings. Incandescent light is high in the red or orange range, but generally produces too much heat to be a valuable light source for plants. Fluorescent grow-lights attempt to imitate sunlight with a mixture of red and blue wavelengths, but they are costly and generally no better than regular fluorescent lights.
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loaches r cool said:
Algae uses photosynthesis... meaning it will be about the same. The difference being that algae I believe has more accessory pigments so it can utilize a broader spectrum of light. I believe I read somewhere that cyano can utilize green wavelengths which few plants can. Algae and plants are very similar. Think of it like weeds in your garden. The weeds and veggies use the same light and same nutrients. Weeds are just more opportunistic and when the conditions arent ideal and veggies arent doing well the weeds sure still can be... same thing with algae.
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If all of the above information is true, then the 6700k bulbs (Shown above) that I have been using (which put off a distinct green hue) are actually more prone to grow algae than the Full Spectrum, 10000k, and Actinic bulbs I listed above. 6700k bulb are touted as being on of the best plant bulbs, it is beginning to appear that science contradicts that?
 
livingword26 said:
If all of the above information is true, then the 6700k bulbs (Shown above) that I have been using (which put off a distinct green hue) are actually more prone to grow algae than the Full Spectrum, 10000k, and Actinic bulbs I listed above. 6700k bulb are touted as being on of the best plant bulbs, it is beginning to appear that science contradicts that?
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livingword26:

Nope.

1) the 6700K bulbs are what I call "grow light" bulbs in that the spectrum which they emit is close to sunlight.

2) I do not understand "the distinct green hue business". Mine just appeared as a very dull whitish light (which is the reason that these bulbs are in the garage now).

3) Prior to MH I only had two 10000K and two 7100K bulbs.

4) IMHO please forget your concept of the "algae business" as, once again IMHO, our aquarium plants are much more efficient in their utilization of light and nutrients than are algaes.


Tristan:

It is my turn now!

Did you say that the two 7100K bulbs which I have in my PC's are beneficial for my plants??

Also, and as usual you have really done your homework, some of the literature suggests that red light may also be beneficial to plants.
What is your opinion?

TR
 
jones57742 said:
livingword26:

Nope.

1) the 6700K bulbs are what I call "grow light" bulbs in that the spectrum which they emit is close to sunlight.

2) I do not understand "the distinct green hue business". Mine just appeared as a very dull whitish light (which is the reason that these bulbs are in the garage now).

TR
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Kelvin rating, from brand to brand, does not always emit the exact same light spectrum. The coralife 6700k t-5 tubes that I posted about earlier have a very green hue. I have all 4 of those bulbs and the hue is clear. The full spectrum has pinkish hue, the 10000k is white, perhaps faintly blue, The 6700k is green, and the Actinic is of course blue.
 
livingword26 said:
If all of the above information is true, then the 6700k bulbs (Shown above) that I have been using (which put off a distinct green hue) are actually more prone to grow algae than the Full Spectrum, 10000k, and Actinic bulbs I listed above. 6700k bulb are touted as being on of the best plant bulbs, it is beginning to appear that science contradicts that?
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Well actually you could look at it that way. Most plant grow bulbs have very little green at all... I have had a couple, last one being the Aqua-Flora Plus (a T6 bulb by Quantum) and it is very purplish and emits most of its energy in the reds and blues (hence purple). But as far as promoting algae with green light... like I already said just about anything that is good for plants is good for algae too anyhow, so just focus on promoting the plants. And green light makes are plants look so nice.

Human eyes are great at automatically adjusting to various lights... often times you dont realize the color of a bulb as anything but 'white' until its next to another bulb. But yes, many very popular daylight spectrum bulb have a heavy amount of green, which makes them look brighter to our eyes (lux, lumens). For example here are two 6500K bulbs I have that definitely have a green cast:

lights.JPG

3rd bulb in from left is Philips Daylight Deluxe 6500K


GE Starcoat 6500K T5HO on top, definitely green. However the Giesemann 6000K midday bulb (2nd up from bottom) has no greenish cast but is a tad yellower.

Note the apparent colors are enhanced by a fast shutter speed of the camera. To the naked eye they are much brighter and more whitish.

I am not promoting the use of actinics. Just trying to say they arent some evil thing that will make your plants dissolve and algae prosper (unless of course you dont provide plenty of other light, nutrients, co2, etc). They only put out a very small portion of light usefull for plants. Tom Barr says it best I think, plants like a lot of reds with a little blue. ;)
 
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livingword26 said:
Agreed the Actinic is not good for plants.
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I'm agreeing with this, but I just wanted to state this more clearly. Actinic is not beneficial to plants. It won't harm them, but assuming limited space for bulbs, it's a waste of space for plants.

A lot of people do leave these on there cause they like the color. Assuming you have enough of ~6700K light, actinic won't "hurt" your plants.
 
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