[MeCasa]

Fish and aquarium aside.

Simply for plant growth on deep tank, would you use varying color led's or just White?

Thanks
MeCasa

 

[allabouttheplants]

What wavelength of "white" ? 2300k, 2700k, 3100k, 4200k, 5000k, 5700k, 6000k, 6500k.
For best plant growth 5000k-6500k.

 

[Solcielo lawrencia]

It's the spectrum, not the Kelvin, that matters to plants. You'd only need deep blue and deep red to grow plants. Looks terrible.

 

[jeffkrol]

Fish and aquarium aside.

Simply for plant growth on deep tank, would you use varying color led's or just White?

Thanks
MeCasa

I don't think anyone here would be surprised by me saying "varying color" LED's
http://www.ledgrowlightshq.co.uk/led-grow-lights-what-to-look-for/

For anyone who doesn’t want to bother reading all my drivel above, here’s the summary of what I think an ideal LED grow lamp should have:

1. Red LEDs within the range of 620-710nm with special attention provided for the 660nm wavelength
2. Blue LEDs 425-495nm
3. UV LEDs 300-400nm
4. Far-red LEDs 710-800nm (especially around 730nm)

Anything other is mostly (arguably) aesthetics....Except for UV, the above can be sufficiently covered w/ a ratio of cw/ww in proportion to what you find appealing..

I do have an "opinion" on the stimulation of ancillary pigments (carotenoids mostly) but that is a story for another day..

 

[Solcielo lawrencia]

How many aquatic plants have carotenoids for the green spectrum to be relevant?

 

[jeffkrol]

How many aquatic plants have carotenoids for the green spectrum to be relevant?

There like ancillary "hormones" if a leaf turns yellow, that is the carotenoids.. usually the chlorophyll has been reabsorbed (waste not want not) by the plant (fall )
The "red" is xanthrophylls.. also related..

http://plantphys.info/plant_physiology/light.shtml

Chlorophyll is not the only photosynthetic pigment

So "cyan" is arguably the closest LED.. I did mention it was my personal opinion and a "why not cover all bases".. Straying from "purple" (R/B specific plant lights) it is all "compromise".. a bit..

some is "questionable" of importance based on "species specific" grounds.. Generalization is the best we can do..or really need to do.. Like I said a mix of ww/cw pretty well satisfies the main critera...
more than most care to know:

Chlorophyll a has an approximate absorption peak of 665 nm and 465 nm.
Chlorophyll b has an approximate absorption peak of 640 nm and 450 nm.
Pheophytin a has absorption peaks at 666.6 nm and 408.8 nm
Pheophytin b has absorption peaks at 654.2 nm and 433.2 nm
Beta-carotene absorbs most strongly between 400-500 nm.
Xanthophylls absorb best at 400-530nm.
Betacyanins are reddish to violet Betalain pigments. They absorb light best at 535 nm.
Betaxanthins are yellow to orange Betalain pigments. They absorb light best at 480 nm.

Anthocyanin absorption depends on the pH the pigment is in.
At a pH of 1.0, most anthocyanins absorb light between 460 and 550 nm with a peak at about 520nm for the molecule class in general.

PLANT soup............

 

[MeCasa]

I already have RGBW left over from the tank lights. I'm running specific lights on a timer directly above my plant area so I don't over-light the entire tank and possibly cause algae problems.

Sounds like some spectrum available in the RGBW will work

And they're paid for

MeCasa