Aqua Man's 24hr trivia for rights to edit my signature

[Aqua Man]

Well it's GREEN of course.

 

[Moe.Red]

Well it's GREEN of course.

Man, you are going to have to show your work on that for full credit.

 

[Aqua Man]

The reason it's not blue or red is the photosynthetic efficiency of spectrums change with intensity.

At low intensity.

Red is most efficient as all photons are used towards photosynthesis.

Blue is second partially because some of the photons are used for carotenoids.

Green is less efficient as it needs to penetrate the leaf deeper.

So how does this change with intensity?

Simple put just like efficiency of light output per watt in our fixture plants also produce heat as a waste byproduct.

Red and blue are absorbed closer to the leaf surface and excite the chloroplast much greater than green does and this increase with intensity.

So at high intensity green is actually more photosynthetically efficient than both.

 

[Aqua Man]

Almost all the science we hear is at low intensity of 200-400 ppfd. So while it's true under those conditions it's not true at high intensity like 1000+ ppfd.

Simply put variable matter and in cannabis there is no one right answer for all scenarios and if this isn't something almost everyone think is a single right answer that's makes that point idk what is.

And that's why I tossed in the intensity

 

[Aqua Man]

Congrats @XhibitA and @detroitjoe.

I was not expecting a single correct answer. So this week @XhibitA since he was forst and next week @detroitjoe.

I'll link supporting evidence shortly.

 

[Aqua Man]

Frontiers | Photosynthetic Physiology of Blue, Green, and Red Light: Light Intensity Effects and Underlying Mechanisms

Red and blue light are traditionally believed to have a higher quantum yield of CO2 assimilation (QY, moles of CO2 assimilated per mole of photons) than gree...

www.frontiersin.org

Here it is and it has been peer reviewed.

 

[Moshmen]

Almost all the science we hear is at low intensity of 200-400 ppfd. So while it's true under those conditions it's not true at high intensity like 1000+ ppfd.

Simply put variable matter and in cannabis there is no one right answer for all scenarios and if this isn't something almost everyone think is a single right answer that's makes that point idk what is.

And that's why I tossed in the intensity

Tricky! One word changed the answer, under low intensity would it be blue then ?

 

[Aqua Man]

Tricky! One word changed the answer, under low intensity would it be blue then ?

Red

 

[Aqua Man]

Sig working @XhibitA ?

I'm on mobile

 

[Saul.Goodman]

Negative on landscape mobile at least.

Neither mine though now. I'll check the site via browser.

 

[Moe.Red]

That's very interesting! My only gripe is that this is a study of things like lettuce and spinach, not a tree like cannabis. The details of light penetration to lower parts of the plant are not really discussed and could account for a different result in taller woody vegetation.

I'm going to re-read that when I have more time, unexpected results that go against your current thinking are always the most fun.

I wonder what a pot plant would look like if grown completely under green only from seedling to flower at higher PPFDs. I can see that being a fun experiment.

 

[Aqua Man]

That's very interesting! My only gripe is that this is a study of things like lettuce and spinach, not a tree like cannabis. The details of light penetration to lower parts of the plant are not really discussed and could account for a different result in taller woody vegetation.

I'm going to re-read that when I have more time, unexpected results that go against your current thinking are always the most fun.

I wonder what a pot plant would look like if grown completely under green only from seedling to flower at higher PPFDs. I can see that being a fun experiment.

Has to be green with white I believe. To much green will reduce growth in cannabis.

 

[Moe.Red]

Has to be green with white I believe. To much green will reduce growth in cannabis.

Yes, I totally get that.

In terms of your question and the way it was asked, one could have the takaway that we need more green light, and that all green is best. But I don't believe that is the reality for what we are trying to do with these plants. It is not all about converting CO2 into sugar as fast as possible. The different spectrums have a huge impact on plant morphology.

Also, lettuce does not flower, I wonder what the results would be if this experiment was re-run on a flowering plant. Lettuce is nothing but leaves in a short squatty package that will use light differently than an oak tree.

Seems to me, green would be best used in the veg stage for our purposes. All very interesting to ponder, great thought provoking question.

 

[Aqua Man]

That's very interesting! My only gripe is that this is a study of things like lettuce and spinach, not a tree like cannabis. The details of light penetration to lower parts of the plant are not really discussed and could account for a different result in taller woody vegetation.

I'm going to re-read that when I have more time, unexpected results that go against your current thinking are always the most fun.

I wonder what a pot plant would look like if grown completely under green only from seedling to flower at higher PPFDs. I can see that being a fun experiment.

Hey where ya been?.... I was thinking and mentioned to to someone the other day. Hope all is well.

Food for thought. It all makes total sense to me.

HPS will out yield MH at any intensity

LED will out yield both at high intensity.

Adding the white to blurples like current LED will outperform blurples.

Leaf temp is not only lower under under LED because of IR but at high intensity but the higher green to red and blue ratios.

And as always intensity trumps spectrum for growth until high intensity.

 

[Aqua Man]

Yes, I totally get that.

In terms of your question and the way it was asked, one could have the takaway that we need more green light, and that all green is best. But I don't believe that is the reality for what we are trying to do with these plants. It is not all about converting CO2 into sugar as fast as possible. The different spectrums have a huge impact on plant morphology.

Also, lettuce does not flower, I wonder what the results would be if this experiment was re-run on a flowering plant.

Seems to me, green would be best used in the veg stage for our purposes. All very interesting to ponder, great thought provoking question.

Imo uts all about balance and lacking in any spectrum is ot good.

Blue is the lowest at high intensity but carotenoids are important.

Oh a thought way off topic on that. Are the antioxidants produced by them and anthocyanins partially responsible for preservation and longevity of terps etc.?

I'll link another thread I have like a million times that goes into much more detail on the spectral effects on the photobiological and morphology of cannabis.

Much more rounded but lacked this detail.

Frontiers | An Update on Plant Photobiology and Implications for Cannabis Production

This review presents recent developments in plant photobiology and lighting systems for horticultural crops, as well as potential applications for cannabis (...

www.frontiersin.org

 

[Cashmeh]

Complete guess, not reading others reasoning either.

I would say green due to the leafs being green. I mean wouldn't it be easier to consume the light that's it's natural color? Also wouldn't green be able to penetrate green leafs easier?

This will be the least scientific comment here lol.. Not much data to back up my claim

 

[Aqua Man]

Complete guess, not reading others reasoning either.

I would say green due to the leafs being green. I mean wouldn't it be easier to consume the light that's it's natural color? Also wouldn't green be able to penetrate green leafs easier?

This will be the least scientific comment here lol.. Not much data to back up my claim

Right answer at high intensity but take a look behind the reasons. Green can be the highest, middle or lowest efficiency depending on intensity.

 

[Cashmeh]

Right answer at high intensity but take a look behind the reasons. Green can be the highest, middle or lowest efficiency depending on intensity.

Meant to say I havnt read them at that time, gonna read the reasonings now.

 

[Moe.Red]

Imo uts all about balance and lacking in any spectrum is ot good.

Blue is the lowest at high intensity but carotenoids are important.

Oh a thought way off topic on that. Are the antioxidants produced by them and anthocyanins partially responsible for preservation and longevity of terps etc.?

I'll link another thread I have like a million times that goes into much more detail on the spectral effects on the photobiological and morphology of cannabis.

Much more rounded but lacked this detail.

Frontiers | An Update on Plant Photobiology and Implications for Cannabis Production

This review presents recent developments in plant photobiology and lighting systems for horticultural crops, as well as potential applications for cannabis (...

www.frontiersin.org

I thought this segment was interesting from the paper:

Cannabis plants grown under blue light with a short photoperiod (12 h light:12 h dark/flowering stage) improved cannabinoid content (Magagnini et al., 2018). This same study suggested that there is a synergy between UV-A and blue wavelengths that induces cannabigerol accumulation in cannabis flowers.

My personal testing bears this out.

And this

A low percentage (≤ 24%) of green light enhanced plant growth, whereas plant growth was inhibited under a higher percentage of green light

I find interesting. Taken together, these 2 studies say that green at high PPFD promotes the highest CO2 consumption, and therefore photosynthesis, however when you supply more than 25% green you actually stunt the plant.

My takeaway is that highest possible photosynthesis is not our goal when growing cannabis, if large cannabinoid rich plants is what you are after.

I wish @Milson was still around, he was always able to cut thru the chaff on these kinds of papers and pull out the nuggets important to us growers.

You mention that HPS>MH above, I think perhaps that generalization does not hold 100%. I run Eye Hortilux bulbs with this spectrum in my non-LED tents, and after more than a dozen grows, I find this bulb / spectrum outperforms all others in terms of size and cannabinoid profiles.

I'm starting to see why that might be. Your original paper also discussed Orange - this bulb has a lot more green and orange than most of the other light sources out there.

so cool.

 

[Treecutter]

Lol, kind of weird question because you would want all 3. I would also say indoor and outdoor would make a difference too. Red wavelengths encourage stem growth, flowering and fruit production, and chlorophyll production in the later months outdoors but thats due to short cold days and the red gives it radiant warmth.

Blue is absorbed more by the chlorophyll and transposed to energy and green is absorbed by photoreceptors which is also needed.

More UV produces more resin production or frys the plant.

So still all 3 but strictly photosynthesis on a healthy plant converted to energy for growth would be blue depending on how bad you lollipop your plant. Stripped down i would say red but without all 3 together there's no use in the discussion because you plant is now compost.