what's up with more red than blue?

Ready to get flamed, but I've lurked for a long time now, and for LED lighting it seems the complete consensus is the ratio should heavily favor Red to Blue even for Veg growth.

I've searched long and far and having not done the experimentation myself, for veg growth I would like to know up front opinions on LED lighting. Specifically I want to mention Pr0f's wonderful "LED without LED - My First T5 grow" study where it seemed (correct me if I'm wrong) that Pr0fesseur favored blue all the way through veg growth. Am I wrong?

I am also reading people may be shying away from blue in choice for white. Is this because blue isn't as needed as previously thought?

Clearly I'm confused. I am aware of the spike on the blue end for photosynthesis, but what's up with everyone's concern with red?

LED on the market are a blend of lightwaves ............they are going into the area of trying to find the prefect blend to get the best growth

picking a led maker is kind of a big thing due to the cost of the units and the lightwaves (once they have something they patten it so only they can make that blend of light)

currently the 2 leaders are Blackdog and Black Star.............it is a toss up on who has the better blend but they are both very well made and designed lights.......they will get u a nice plant and last u longer then my bulbs will (dual arc bulbs are 150-169 for 1 for 20,000 hours maybe)

Whites cover a more full spectrum where just blue and red lacked green, amber, and IR. Green drives photosynthesis by helping pigments absorb more photons in other spectral regions. 660nm deep red combined with IR improve and drive flowering. (emerson effect). Top 3 companies who all use Cree and Nichia (top of the line) best deal for the money. Area51 lighting, apache tech, and hans led. They have the highest par output (umole/s) and the best warranties and customer service.

justugh said:

LED on the market are a blend of lightwaves ............they are going into the area of trying to find the prefect blend to get the best growth

picking a led maker is kind of a big thing due to the cost of the units and the lightwaves (once they have something they patten it so only they can make that blend of light)

currently the 2 leaders are Blackdog and Black Star.............it is a toss up on who has the better blend but they are both very well made and designed lights.......they will get u a nice plant and last u longer then my bulbs will (dual arc bulbs are 150-169 for 1 for 20,000 hours maybe)

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Ehhh.... neither of those companies are 'leaders' IMO.

Both companies use no-name LED's. If you want top quality LED's, look at Apache LED and Area 51. Area 51 uses CREE diodes (REAL CREE Diodes) and Apache uses Nichia diodes. Both are exceptional quality, and are more efficient and produce more umoles/w than Blackstar or Blackdog. I own a bunch of Blackstar panels, they're o.k. but their spectrum sucks, and Blackdog aren't very efficient, although I've seen lots of grows that prove they can produce nice buds.

Make the right decision the first time (I didn't) and go with quality from the start, you won't be disappointed.

For references you can view The Dawgs, Tags420 (Greengenes), or my own journals. Lots of pics, lots of proof.

Hope this was helpful!

hyroot said:

Whites cover a more full spectrum where just blue and red lacked green, amber, and IR. Green drives photosynthesis by helping pigments absorb more photons in other spectral regions. 660nm deep red combined with IR improve and drive flowering. (emerson effect). Top 3 companies who all use Cree and Nichia (top of the line) best deal for the money. Area51 lighting, apache tech, and hans led. They have the highest par output (umole/s) and the best warranties and customer service.

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Guess I should have read your post before posting. lol

thanks for the feedback everyone.

And PetFlora, I'm so glad you joined the conversation because I've seen many comments on this topic from you that I wanted answers to!

I should have mentioned the LED I use are all bought a la carte from "Rapid LED". I enjoy building my grow lights myself. The problem is there seems to be an abundance of missinformation when it comes to ratios.

For instance, everyone recommends LED ratios favoring the Reds MUCH more than blue. I've seen 8:2 in some instances not even meant for specifically flowering. EXCEPT: One of the best reads I've found on this site was Pr0f's "LED Without LED - My First T5 Grow" which is very confusing as it appears to focus way more on blue spectrum than red. Now that's with T5 but why is that different than LED?

And with recent focus on green (in the form of white) I want to make sure to include those LEDs as well. I've even seen some indicate they've done away with blue altogether because they've gotten what they need from White. This further makes me want to know why people favor red to blue. I've seen the photosynthesis charts and see the spikes in red and blue, but the blue spike is larger than red. I simply want to know why the focus is on red even for vegetative growth.

Specifically I want to know once and for all what these ratios should be. And that is my only question here. I want to know ratios from first hand experience, through experimentation or understanding.

PetFlora said:

Alas, you will get biased disinfo when not doing your own research, which having spent 3 years researching.... so combining just NW + WW will do a hell of a job...

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Specifically I believe PetFlora is onto what I'm asking. And I know he's been researching for a very long time so probably has the answers I'm looking for. Please forgive me but what is NW + WW and are you suggesting I could work wonders with just that! (EDIT: I realize that you meant Neutral + Warm White, duh! But again, this all favors Red, or rather disfavors Blue, why no Cool White!? Either way do you feel I would be well off with just white without too much wasted efficiency?)

Further I am only concerned about vegetative growth, and here's where I'm going to get myself in trouble. I grow mostly cooking herbs (not the superb-herb). Why am I on a grower's website? Well, because from all my experience you guys have the most knowledge. I understand other plants react differently to light, but feel all the research gone into your industry makes for an excellent starting point for growers of other plants.

Thanks for listening and I would greatly appreciate any advice on lighting ratios.

From experience, using too much red in veg makes plants too short and too dense. It affects light penetration in flower, and the plants suffer. Using too much blue in flowering stunts growth, and makes plats seem laggy and slow.

While using blue light in veg promotes healthy spacing and growth, and using red light in flowering promotes bud growth, as well as denser product.

I'm not a horticulturalist so if you're looking for the complete scientific picture I might not be the best source of information. I do however have lots of practical knowledge from using my LED's over many grows/years.


If you think about the seasons and how the light changes from June to October, it becomes more red/orange. It makes sense plants would adapt to get the most out of each season.

I did the whole t5 thing for years, the last batch of it I did, I had the best results with white 5400k htg and 630 uvl redsuns. Originally in that thread prof thought the fiji purples had a different spectrum than they do. Hence the more blue. I started doing the exact same bulb set up as Prof and changed it each run over a span of 2 years. You want blue and red in both veg and flower. The whites cover both ends and everything in between. At the end Prof came back ( a couple months ago) preaching the same shit. Not realizing how far leds have come and surpassed t5 and hid.

Beefbisquit said:

From experience, using too much red in veg makes plants too short and too dense...
I'm not a horticulturalist so if you're looking for the complete scientific picture I might not be the best source of information. I do however have lots of practical knowledge from using my LED's over many grows/years...

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It was my understanding that red encourages vertical growth, and that more blue makes for shorter plants, not the opposite. Was I wrong? I completely understand the shift to red for flowering as summer's red/orange glow sets in. But for vegetative growth this is why I'd think Blue should be more important than the small ratios that have been mentioned here and elsewhere. 8:1 seems so miniscule for perhaps an under-appreciated spectrum.
thanks, it is your knowledge from experience that I am after! horticulturalist aside, sometime the scientific picture can be too.... scientific..

hyroot said:

..I had the best results with white 5400k htg and 630 uvl redsuns... Originally in that thread prof thought the fiji purples had a different spectrum than they do. Hence the more blue. I started doing the exact same bulb set up as Prof and changed it each run over a span of 2 years. You want blue and red in both veg and flower. The whites cover both ends and everything in between. At the end Prof came back ( a couple months ago) preaching the same shit. Not realizing how far leds have come and surpassed t5 and hid.

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So Pr0f's original setup incorrectly favored the Blue end of the spectrum? His thread was the one evidence I had to support why Blue should be at least equally as available as Red. My original question was why do people favor red over blue (even if photosynthesis seems to use more blue than red). What experience or knowledge do you have to support this reasoning.
Though I am beginning to understand the importance of whites for and all in one solution. But why does everyone focus on red over blue?

It's my understanding that red during veg makes for short, squat plants; a desired trait to an extent, but using a flowering panel (like my blackstars that have a heavy red/blue ratio) caused my plants to cease any kind of a stretch, to a fault. The plants weren't able to get light into the bud sites as well as if they were spaced out a little more.

Now if I have to use an all red/blue panel for vegging I back it waaaay off, and let the plants reach for the light (much more so than if I just use veg mode on a different panel).

rashomon said:

Specifically I believe PetFlora is onto what I'm asking. And I know he's been researching for a very long time so probably has the answers I'm looking for. Please forgive me but what is NW + WW and are you suggesting I could work wonders with just that! (EDIT: I realize that you meant Neutral + Warm White, duh! But again, this all favors Red, or rather disfavors Blue, why no Cool White!? Either way do you feel I would be well off with just white without too much wasted efficiency?)

Further I am only concerned about vegetative growth, and here's where I'm going to get myself in trouble. I grow mostly cooking herbs (not the superb-herb). Why am I on a grower's website? Well, because from all my experience you guys have the most knowledge. I understand other plants react differently to light, but feel all the research gone into your industry makes for an excellent starting point for growers of other plants.

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I'm pretty sure those whites he's recommending contain a lot of blue spectrum in them.

there are more photons in blue regions. Chlorophyll absorbs more deep red than blue, but thats where green comes in... People assume more red means more yield. Like people think more phos or more potassium means bigger buds. Simply not the case. A balanced spectrum and diet sort of speak makes for overall better everything. Look at the sun. It never changes except for the hours and the infrared it puts out year round along the equator and at the end of summer and fall in the rest of the world.

bondoman said:

I'm pretty sure those whites he's recommending contain a lot of blue spectrum in them.

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I buy Cree XP-G and here's the Relative Spectral Power Distribution of cool, neutral, and warm. http://img849.imageshack.us/img849/5571/xpg.png
They do in fact contain a decent amount of blue, but specifically my question is why more emphasis is on red than blue (not no blue, just why not as much blue!)

hyroot said:

there are more photons in blue regions. Chlorophyll absorbs more deep red than blue, but thats where green comes in...

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What I need clarification on is how is this true based on this spectral analysis of chlorophyll A & B, I'm not mentioning other important elements for simplification. http://en.wikipedia.org/wiki/File:Chlorophyll_ab_spectra-en.svg
In this picture you clearly see the Blue region having a greater area than the peaks in the red region! Is the key when you mention "there are more photons in blue regions"?--can you elaborate. Thanks!

hyroot said:

A balanced spectrum and diet sort of speak makes for overall better everything. Look at the sun. It never changes except for the hours and the infrared it puts out year round along the equator and at the end of summer and fall in the rest of the world.

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I definitely understand the need for a balanced diet. Just am curious why everyone focus's on Red when based on the picture above Blue seems to take up a larger area. I understand why for flowering, but why for vegetative growth!? Also, I'm curious why the sun's infared isn't notably higher in spring, since that would be the same as fall in term of how the earth tilts.

I know what you're saying. But in my own tests I've done in vegging, my Philips 2700k LED Bulbs 11w(2 of them) had the same growth as 2 CFL 13W 6500k bulbs, and the Philips plants looked healthier. Granted I think the philips I'm using leak more blue than the usual 2700k, but surely the 6500k had more of it. I'm in the middle of testing the same Philips bulbs with phosphor removed(royal blues) on a seedling, to see what happens. It's as blue as you can get with nothing else.

I think maybe what you are seeing is that a lot of us use the same lights for veg that we use for flowering, which tend to be heavier on red, and they do a great job still.

I've always preferred more blue in veg than red. Even when using hid, I'd rather veg with metal halides than hps. Just look at companies producing veg lights, they are more blue than red, some even produce all blue panels.

According to KNNA as of Oct 2009:
"Working with PAR watts, cannabis is growing the best with 60-75% of Red, 10-25% of blue and 10-25% of green-yellow."

If blue weighted vegging was ideal I expect KNNA and his testers would have figured that out many years ago. They were starting from scratch and empirical studies were the quickest way to get a ballpark idea of which spectra were the best for which stage of growth.

If I recall, it was possible to veg with pure blue 450nm but growth was significantly enhanced by adding red 630nm. Once you have a sufficient amount of blue (20-30%), internode distance is under control and there is no advantage to adding more.

My veg lamp uses 28% blue, 42% red and the remaining 30% is the non-blue part of the warm white (PAR watts). Internode distance is a perfect one size fits all, no complaints.

This is all great info, thanks! Even though some may be repeating each other it is really helpful to hear it from different perspectives as it gives me a clearer picture.

I do wonder if KNNA's info might be a little outdated at this point with advancements in LED. If only PetFlora would chime back in since I had specific questions for him. Also would love to hear further clarification from hyroot regarding the questions in my last post. Anyone?

If you think back to when the Proffessor started the led without led's thread, he was trying to imitate led's at that time, which pretty much just came in red and blue for growing. (I followed it too). He was going by the best information and technology at that time, which has come a long way since then.

As far as everybody favoring red, I think it's because everybody is now using them to flower and not just veg, and they are trying to get the best spectrum they can for flower knowing that it will also work fine for veg. Just my 2 cents

rashomon said:

I do wonder if KNNA's info might be a little outdated at this point with advancements in LED.

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Efficiency has changed, but not the spectra available for testing.

If neutral whites are what you are interested in, they do a great job vegging without red augmentation, although they are strongly weighted in red. Even better, they are some of the most efficient LEDs on the market. The XML2 4500K T6 bin is 43.2% efficient at 700mA 50c and it is only $4 on a 20mm star.

I have some running for veg at 350mA with a Tj of about 40c so they are putting out about 165 lm/watt and running at 47.5% efficient. 6 dissipation watts covering 1.5-2sq ft. Growth is fast and internode distance is tight.