# Light spectrum and plant growth - where are the reds?



## EvilLost (Jan 10, 2011)

I have recently been researching LED lighting (and am eagerly awaiting my first package!) and have come to realize that 6500K lights that I've grown to love do not actually contain the red wavelengths that will promote plant growth. In hindsight this is perhaps obvious...


I see very little discussion on this matter....is there a reason that pure daylight is promoted over a different color spectrum that may promote better growth? 

Looking at the reefing hobby, actinic lighting and in general considerations for blue wavelengths are given. I've no experience with reefs, but from my understanding this is to promote the coral growth/coloring because the blue light is beneficial to the coral; is this wrong? Is the light purely an aesthetic trick?


In any case, I'm fairly certain that the red wavelengths help photosynthesis and plant growth in general. Yet most 6500K lights are of course not exactly 6500K but typically in a 5000-8000K spread....which may include some beneficial blues, but it is pretty far out of the reds...


The only thing I can think of is aesthetics; that the red would overpower the tank and make things look "funny". Perhaps this would be an issue from the frogs perception as well? I'm not sure...


----------



## phender (Jan 9, 2009)

It depends on which 6500K bulbs you are looking at. 6500K fluorescent bulbs tend to have plenty of light in the red spectrum. When I see a spectral analysis of 6500K LED lights I don't see much red at all. The spectrum looks more like what you would see from a 12000K bulb. 
I am not a horticulturist, but from what I understand 6500k lights are used for growth and the 3000K (much more red) are used for blooming.
FWIW, the Kelvin rating on lamps doesn't necessarily tell you the wavelengths of light it produces, it tells you the overall color appearance of the light. I suppose there are lots of color mixes that would give you the same overall appearance, so not all 6500K lights have to emit the exact same wavelengths of light.


----------



## Venutus1 (Feb 13, 2010)

phender said:


> It depends on which 6500K bulbs you are looking at. 6500K fluorescent bulbs tend to have plenty of light in the red spectrum. When I see a spectral analysis of 6500K LED lights I don't see much red at all. The spectrum looks more like what you would see from a 12000K bulb.
> I am not a horticulturist, but from what I understand 6500k lights are used for growth and the 3000K (much more red) are used for blooming.
> FWIW, the Kelvin rating on lamps doesn't necessarily tell you the wavelengths of light it produces, it tells you the overall color appearance of the light. I suppose there are lots of color mixes that would give you the same overall appearance, so not all 6500K lights have to emit the exact same wavelengths of light.


yep.

white versions of LEDs are a little low by nature in there ability to generate much red.
BUT they do produce some.
Also, lumen/ lux count when growing plants too.
I have added a line of LEDs that incorporate SOME warm white chips to boost that end of the spectrum.
(and have had 3 full spectrum prototype models just tested by F.Baines in UK to work towards the holy grail... a full (visual spectrum) LED unit.

But *ehem* that is proving more difficult than first thought.. 
UGH.
We (Luo w/ the factory in Shenzhen & myself) have been at if for 5 mo. 
Matching the visual spectral curve exactly of sunlight using LEDs is much trial and error (and greenbacks $$!). 

Anyway, for right now, using the 4.5k warms interspersed with the cooler day-white 6.k has created a good use of what is currently available in LEDs to get good ++ light.
SHORT OF USING mixed lighting :
That is the LEDs mixed w/ a full spectrum Arcadia 6.0,, reti-sun 5.0, Ulra Sun or Indoor Sunshine CFL... or depending on the mix/proportion of out-put- an aquari lux or gro lux bulb. 

Cheers!
Todd

oh ps.. I am doing an LED spotlight now that pulls about 17w that has REd & Blue LED added.

Rob at Little Frog Farm [email protected] is trying some on some orchids right now I think, as we speak.
btw- he is the one with the freekin' nice orchid room that there are pics of up on dendro. 
He has got some beautiful plants.


----------



## motydesign (Feb 27, 2011)

ive been working with LEDs for about 7 years now and their wavelengths and seen HUGE steps with output and color availability 
like you say if you go for plant growth it looks funny. this is a tad grow out that has 10 10mm whites , 20 5mm yellows, and 40 4mm reds. im promoting natural algae growth for the tads. anyway just thought you would like to see what kind of hue /color you can expect.


----------



## EvilLost (Jan 10, 2011)

thanks thats more or less what i thought was going on!


----------



## DragonSpirit1185 (Dec 6, 2010)

Venutus1 said:


> yep.
> 
> white versions of LEDs are a little low by nature in there ability to generate much red.
> BUT they do produce some.
> ...


I have thought about using a Jungle Dawn LED bulb and then on the other light socket using a lower spectrum bulb that is geared more towards the reds.

If I did do this what type of CFL would I need to get, maybe a 2700k or 3000k CFL?
What do you think of this for my 10g vert, would just one of those LED bulbs and then a CFL work?


----------



## EvilLost (Jan 10, 2011)

@Dragonspirit: I don't follow...why do you need both? In general the things we are referencing in this thread are for larger enclosures or grow-ops in general.

A 10g tank will be fine being lit by just a 6500K bulb. I'd stick to CFL as the cost difference is simply not worth it imho. 

From my understanding on the jungle dawn LEDs, they are a mix of 6500 and 3000K LEDs, but I have not seen any specs on the LEDs used (not all LEDs are the same even with the same light temp). It is important to understand that the same color temperature can be created by DIFFERENT mixtures of light; so to find out if you have reds you have to see the spectral graph of the source in particular you are referencing. Just because you get lower temp bulbs does not necessarily mean you have more reds (although it likely does).

Honestly, I don't think any of this becomes relevant until you get to LARGE enclosures or commercial grow-ops like I said before, but I am trying to understand the deeper science behind it personally.

From a practical perspective, whatever second bulb you add (3000K or 6500K) won't really matter in terms of your plant growth (due to the size), it will jsut affect whether the tank looks more "white-daylighty" or "orangish-householdy" and I guess ultimately thats up to you (though I prefer 6500K).


----------



## bobrez (Sep 10, 2011)

I find that it is awsome that you can produce white light from mixing RGB leds and also can make practicaly any color


----------



## DragonSpirit1185 (Dec 6, 2010)

EvilLost said:


> @Dragonspirit: I don't follow...why do you need both? In general the things we are referencing in this thread are for larger enclosures or grow-ops in general.
> 
> A 10g tank will be fine being lit by just a 6500K bulb. I'd stick to CFL as the cost difference is simply not worth it imho.
> 
> ...


meh my broms have lost their color and my ficus doesn't light the bright light.
I figured a mix would help them out?
Idk too much about lighting.
I have 2 6500k CFLs


----------



## EvilLost (Jan 10, 2011)

what wattage are your bulbs? that sounds like plenty of light for a small tank.

I have 2x 2' 32W 6500K on my 29gallon tank and its growing wonderfully. Similarly, I have 1 CFL 13W 6500K on my pygmy tank doing great.


Those are my only comparable tanks but I'm fairly confident your light should be sufficient....what do you have on top of your tank? Is there screen or glass? and is it clean? 


I would be pretty surprised if 1x 6500+1x 3000 substantially outperformed 2x 6500....but it is possible for a mild performance? I'd be interested to know actually, but if you change it up dont change both your bulbs at once...change one at a time and monitor so you can see the effects.

If you change to an LED bulb AND a 3k bulb, you won't know which one is having the effects (and the LED bulbs come with a mix of 3k/6.5k i believe anyway)

@bobrez: in theory that should work but in practicality it doesn't really work so well...if the light blends evenly you will get the white, but in my experimentation (which has been limited i admit) there always tends to be one part that is "more red" and one part that is "more green" etc.

I ordered 2 red LEDs to mix with my 24 cool white (6500K) LEDs to promote my plant growth; now I'm still playing with it and some focus lenses....but if I use the red leds "as is" the whole thing just looks ridiculously red (i've tried running 2 blue LEDs at the same time but they dont really seem to mix all that much...I highly doubt that if I add 2 green LEDs the light will balance out....but maybe the next time I order I'll throw down the $10 and find out.


----------



## BR5 (Dec 7, 2009)

Kelvin doesn’t really tell the story of what you want for plant growth; it's more about nanometer wavelength. There are 2 spectrums you want:
1) The first is 400-520nm which has the violet, blue, & green bands that promote peak chlorophyll absorption and influence vegetative growth.
2) The second is 610-720nm which has the red band that is responsible for flowering.

There is not a direct correlation between Kelvin & nm but the higher the wave length the lower the Kelvin rating. Gro-lux bulbs run in the 3000K range, I believe it’s about 3,500; I like to mix one Gro-lux with on 8500K bulb for viewing.

You can search the cannabis growing sites and get inundated with info on this subject. They seem to prefer HID lights which are expensive, use more electricity, and put off allot of heat. There are several people working on a full spectrum LED which would incorporate the nm we need for plant growth and the white light we want for viewing.

Brian


----------



## EvilLost (Jan 10, 2011)

@Brian: yes this was the issue I was initially raising; most HID lights and whatnot put out the full spectrum at least, however LED lighting that I've been looking into does not.


I have a MH bulb in my mini-greenhouse but the heat output is just way too high (and its generally really thick) for me to consider it for any animal enclosure without headache 



I was actually looking at building my own full-spectrum LED light when I ran into this little issue....but finding spectral graphs of bulbs is not always as easy as it sounds :\


----------



## BR5 (Dec 7, 2009)

I'm trying to accomplish the same thing with LED's; ended up purchasing a blue & a red spectrum high output LED for my plant tank. I mounted them at each end so they each shine across the tank toward each other. Above the tank I have one gro-lux and one 5000K 48" T8 light. Here is the web site where I purchased the high output LED's. lighthttp://www.plasmaled.com/high_power_module.htm

Brian


----------



## DragonSpirit1185 (Dec 6, 2010)

EvilLost said:


> what wattage are your bulbs? that sounds like plenty of light for a small tank.
> 
> I have 2x 2' 32W 6500K on my 29gallon tank and its growing wonderfully. Similarly, I have 1 CFL 13W 6500K on my pygmy tank doing great.
> 
> ...


23w
most are 26w but these are some kind of newer thing and I guess they got the wattage down from 26w to 23w


----------



## EvilLost (Jan 10, 2011)

BR5 said:


> I'm trying to accomplish the same thing with LED's; ended up purchasing a blue & a red spectrum high output LED for my plant tank. I mounted them at each end so they each shine across the tank toward each other. Above the tank I have one gro-lux and one 5000K 48" T8 light. Here is the web site where I purchased the high output LED's. lighthttp://www.plasmaled.com/high_power_module.htm
> 
> Brian


Just so I understand, you bought literally 1 of each LED? 2 LEDs total? of the new CREE 3Watts? 


I just received my order from rapidled.com of 24 of the "current" model CREE leds that run at 1.5A rather than 3A ( i wanted the 3A but rapidled didn't carry the other colors and I was just too comfortable with their website). Since I'm still learning all this I wasn't quite ready to dive in too deep...I realize I overpaid a little for that. On my next attempt I will likely go for higher power output on those guys ...assuming all goes well with this build


I also ordered 2 red and 4 blue LEDs (the blue is actually for my moonlight..) but I'll throw up some pics of the various cool white / blue / red combos as soon as I learn how to solder it up right... hopefully I don't fry things (or myself! hah)


----------



## evolvstll (Feb 17, 2007)

EvilLost said:


> @Dragonspirit: I don't follow...why do you need both? In general the things we are referencing in this thread are for larger enclosures or grow-ops in general.
> 
> A 10g tank will be fine being lit by just a 6500K bulb. I'd stick to CFL as the cost difference is simply not worth it imho.
> 
> ...


Just to clarify...........the mixed LED lights offered by Light Your Reptiles are: 75% 6500K and 25% 4500K. Not 3000K as seen in the mass produced LED lights you will find at Costco, Walmart, etc..........


----------



## ₪amphibidextrous₪ (Oct 26, 2011)

If I could weigh in. I may be new to the posting, but I am setting up a new Vivarium, and I have put down the money for (surprisingly  ) two Zoo Med light fixtures. One is the Zoo Med T-8 Flora Sun Max Plant Growth Fluorescent bulb, and Two, the T-8 Ultra Sun Super Daylight Fluorescent bulb. Both of which show great promise in tests, and they are quite inexpensive. Ranging from $15 - $30. They Speed The Growth of Plants exponentially, and are good for most frogs.


----------



## Pumilo (Sep 4, 2010)

₪amphibidextrous₪;684300 said:


> If I could weigh in. I may be new to the posting, but I am setting up a new Vivarium, and I have put down the money for (surprisingly  ) two Zoo Med light fixtures. One is the Zoo Med T-8 Flora Sun Max Plant Growth Fluorescent bulb, and Two, the T-8 Ultra Sun Super Daylight Fluorescent bulb. Both of which show great promise in tests, and they are quite inexpensive. Ranging from $15 - $30. They Speed The Growth of Plants exponentially, and are good for most frogs.


If you are going with T8s, you can get GE or Phillips at Lowes or Home Depot for about 4 or 5 bucks each in the 65K range. They grow plants just fine and are a crisp clean white great for viewing.


----------



## Ed (Sep 19, 2004)

₪amphibidextrous₪;684300 said:


> , and are good for most frogs.


What do you mean by good for most frogs? 

Ed


----------



## evolvstll (Feb 17, 2007)

Pumilo said:


> If you are going with T8s, you can get GE or Phillips at Lowes or Home Depot for about 4 or 5 bucks each in the 65K range. They grow plants just fine and are a crisp clean white great for viewing.


Very true. The t8's where quite a few of the lights I replaced. Something to consider though is the balasts. With the more inexpensive ones you get what you pay for.


----------



## Pumilo (Sep 4, 2010)

evolvstll said:


> Very true. The t8's where quite a few of the lights I replaced. Something to consider though is the balasts. With the more inexpensive ones you get what you pay for.


Agreed. I was referring specifically to the 65K bulbs, not the fixtures. Finding a better fixture with better endcaps could increase the output and would increase bulb and fixture lifespan and safety.


----------



## Dave II (Dec 18, 2011)

Just a thought, I think that spectrum and k-rating is important but just my thoughts on the matter are if you cant enjoy looking at what you have then why bother? Im not saying buy plants that need sunlight to survive and put them under a single 1 watt led because it looks cool. Just saying you should look for what you like and go from there. As far as reefs its both, depending on what your goals are(growth or color ect). I feel the same applies here. Just my thoughts.


----------



## ₪amphibidextrous₪ (Oct 26, 2011)

Ed said:


> What do you mean by good for most frogs?
> 
> Ed


I mean, some pacman frogs cannot handle the light. Something stupid.

And My dad and I went through testing these, and we did the GE, and we did controlled experiments, and the GE didn’t make the plants grow as fast, so… But do any of you know a holder that will hold 2 18” t-8 bulbs? I am need of it desperately.


----------



## ₪amphibidextrous₪ (Oct 26, 2011)

And, can any of you check this page out, I NEED your help!

http://www.dendroboard.com/forum/parts-construction/77354-my-first-real-vivarium.html


----------



## EvilLost (Jan 10, 2011)

@amphibid: what "testing" did you do exactly? 

@evolv: good point, but just because a bulb is 3000K does not mean its "cheap" or "bad". depending on the manufacturer, it could potentially have more reds 

@dave II: I absolutely agree! That was what got me into researching this entire thing to begin with. Like I said earlier I have ordered some red LEDs to try and supplement my lighting, but I am almost positive they will ruin the "look" (and in the case of my display build, looks > growth...the same doesn't hold true in my growout tank obviously)


neither my HD or Lowe's carry 6500K bulbs in any size other than T8 48"....in my quest for them I have found INDUSTRIAL LIGHTING SUPPLIERS (galore)....if you think home depot is cheap!


Most of my stores are now Industrial (Subject matter) suppliers....most sell to the public, and the prices are CHEAP!


6500K 2' T8's are like $1.90 or so....
The fixtures (no reflector) are like $19 for a 2x2' T8 wired ballast...or even cheaper for components if you do the wiring yourself.

the way to go imho


----------



## Ed (Sep 19, 2004)

₪amphibidextrous₪;684328 said:


> I mean, some pacman frogs cannot handle the light. Something stupid.
> .


What Ceratophrys and what light? Where did you get that information? 

Ed


----------

