Spectrum for plants with red leaves

[Slaigar]

Yesterday, I was at the bookstore and I was skimming through a book about planted aquariums(I do not rememebr the author nor title). There were a few pages on lighting & photosynthesis and it mentioned that plants that turn reddish in color in higher lighting use a less efficient way of photosynthesis. The inefficiency is shown as the plants reflect more red.

Now with that said, would that put any more value on the blue spectrum? If this were so, this would definitely make me think twice of buying those grow lights. Especially since more than half my plants are red in color and like high levels of lighting.

This also makes me think that maybe these plants would take more of the green spectrum- though maybe still not a lot.

[KyleT]

As quoted by my friend 2la (helping to spread the message man):

Color temperature says ABSOLUTELY NOTHING about how well a bulb grows plants. Color temperature readings affect nothing more than aesthetics, i.e., how the plants appear to our eyes.

I would think it had more to do with your water chemistry, more specifically what nutrients you are lacking or are in excess of. I unfortunately dont' know which ones though.

Kyle

[2la]

Hehe, thanks, Kyle. Yes, overall lighting intensity is much more important, though a bulb with strong emissions in the red spectrum will, of course, help highlight the red of the plants. To get the reds in the first place, emphasize lighting (and the necessary corollary, CO2 injection), high iron, and low nitrates (<5 ppm). I'm also experimenting with higher levels of phosphates (up to 2 ppm); I will let you know of the results if and when I get them.

[GulfCoastAquarian]

I haven't seen red out of my Sunset Hygro and Rotala Indica in forever. I thought it was due to high NO3, but restricting it to <5ppm hasn't brought on any color. I've dosed iron via Seachem Flourish and Plantex CSM and still didn't see color. I went with Seachem Flourish Iron and some red improved, but phosphate levels dropped quickly. I raised PO4 to around 1.0 and I'm finally seeing some red!
I think my bulbs are getting old, though. I can't wait to get these 9325K bulbs in and see how they affect color. (This might also support the argument for long wavelength spectral output)