Plants, and Light spectrum/wavelength

[DarkSoul]

Quick question, Is 465-470nm a good wavelength of light for plant growth?

[loaches r cool]

Thats hard to say for sure. Is this the only spectrum your lights put out? Like a blue LED or actinic light? There is a lot of anecdotal proof that plants dont like just blue light - needing 'full spectrum' light, but mostly in the blue and red wavelengths. Green wavelengths are needed also to really make the plants glow and look nice to our eye, but not much for photosynthesis. Most plant-specific bulbs focus more heavily on reds and blues and not on greens. Many have said that blue alone isnt good for plants. Again I havent seen much scientific study, just what folks say. Here are a few things that may help you:

http://www.cartage.org.lb/en/themes/sciences/BotanicalSciences/Photosynthesis/Photosynthesis/absorspect.gif

http://www.citruscollege.edu/pic/46/c06_06.jpg

http://tristan.homelinux.net/fish/forum/Color_temp.png

[DarkSoul]

ya i know... i use to grow alot of other plants... "professionally" .... i was just wondering if that is a good spectrum for aquatic plants in general.

I bought a 50p of blue LEDs that put out that wavelength.... I was just considering building an additional blue lighting system for the plants I will have with the 48 left over LEDs I will have :)

no point in doing it though if it isnt going to actually help anything.
they are ultra bright bulbs, 13,000mcd compared to most blue LEDs at 3,000mcd

I know blue spectrum, for what I was doing, resulted in a dense bushy type of growth, when it was used during a certain period of the plants growth cycle, and with an added light cycle for that specific period of growth I can tell you it made for some VERY happy, healthy and large plants.


not sure how it all applies to aquatic plants though :D

from what I see in the chart though, chlorophyll b peaks in absorbtion at about 430nm

[loaches r cool]

I'd say, and I might be going out on a limb :hang: but blue light is definitely good for growth. I think what remains to be seen is how plants will grow under predominantly blue verses blue and red versus full spectrum. Although with a quick search I didnt find it but I have seen graphs like above but showed the action spectrum much greater in the red range than blue, so dont take just one graph for truth. Also, many of the graphs out there just show chlorophyll a and b but dont forget there are a lot of accessory pigments which will utilize other wavelengths. If it were me and I was setting up an LED light setup I'd also at least include the same amount of red leds somewhere around 650-670nm, but thats just me. The white leds are getting better, but getting high efficient high output ones for reasonable price is still in the future I think.

[DarkSoul]

I'd say, and I might be going out on a limb :hang: but blue light is definitely good for growth. I think what remains to be seen is how plants will grow under predominantly blue verses blue and red versus full spectrum. Although with a quick search I didnt find it but I have seen graphs like above but showed the action spectrum much greater in the red range than blue, so dont take just one graph for truth. Also, many of the graphs out there just show chlorophyll a and b but dont forget there are a lot of accessory pigments which will utilize other wavelengths. If it were me and I was setting up an LED light setup I'd also at least include the same amount of red leds somewhere around 650-670nm, but thats just me. The white leds are getting better, but getting high efficient high output ones for reasonable price is still in the future I think.

Well, I will have 4 other T8 bulbs.
11,000K
Dual Day Actinic
and whatever else I purchase when I get the second fixture.

The blue lights would merely be an addition, and used as moonlighting (possibly) I will also be picking up some red LEDs as well, but I might get some high output white ones as well if they do as you mention.

They seem to have very good prices at this store on ebay http://stores.ebay.com/Light-of-Victory-Led-Store-lvehk as well as carrying 60,000mcd LEDs in all colours..... only in 10mm though.

[TwoTankAmin]

Here are two good articles that should help:

http://www.csd.net/~cgadd/aqua/ah_main/mar1998.html
and
http://www.geocities.com/CapeCanaveral/4742/lighting.html