Studies recommend high intensity light: 900 and 1800 mols

[Ca++]

I have another take on this study.

Yield increased proportionally to more light, up to the maximum achieved, 500gpm
500gpm grenerally takes near 1000umol of white light. A level where photo bleaching becomes common with 60% red.

This study is out of wack, because they needed 1800umol to get that yield. The plants were not using the burple very well, to need near double the light. The lights were also 77% red. Except in grow, where they used less blue than in flower. This leaves 23% blue. This blue might be why the plants not performing or bleaching.

Burple is just so different, and poor, that it's studies offer no useful data. What we know about 23% blue giving a 15% yield drop, comes from supplementing HPS. Data that should relate to most lights. Not burple though. It just can't be presumed.

In my recent research, I have found one study gaining 50g+ per 100umol of light added. This was linear, from 600 to 1000umol. Based over a meter, with atmospheric co2. Making that 400umol worth 200g per meter. A tidy gain.
Digging a little deeper, they were looking at dli, in terms of total li over the grow. That 100umol was 200 in li terms, as it was a 45 day bloom. Not bad... making 50g+ (54g) per extra 100umol, on a 45 day cycle.


So that a nice visual divide between white and burple results. Explaining why nobody uses burple, because it's half as good.


It's heavy going: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9551646/
There is a lot on UV in there, that looks good, but I don't have time.

 

[Corpselover Fat]

That is nonsense.

 

[Ca++]

That is nonsense.

Can you be a little more constructive. I at least spelt my name right.

 

[gmanwho]

CA++ for years ive felt that UV ligh is important for terp & trichome production. The plant has grown outdoors for millions if not 100's of millions of years adapting to UV Exposure. The plant wants to protect the seed! UV will sterilize and degrade the seed. In my eyes the trichome is natures advanced light diffuser. Then throw in higher elevation that exposes more UV. All the thrichomes and terpenes are a partial result of uv exposure. Protect that seed to ensure next years replacements!

Im willing to bet that most of the anticancer compounds found in the plant are linked to some sort of UV protection that the plant produces.

Few years back when leds came to market they had no UV, most still dont today. When you talk to MFG reps it was often said they are trying to replicate the sun. So the first thing i said, was is there no UV? It is so important! So why no UV?? The usual response was there is no study suggesting its needed. My immediate response was it may not be "needed" to grow, but i bet a plant grown with UV will produce a better product with increased compounds all day.

So good to see some new data suggesting UV's usefulness

thanks for sharing.

first few things with the study, why only a 45 day trial? no one harvest 45 days, well actually the right thing to say is the plant isnt mature at 45 days. Also, what if these secondary metabolites are not fully formed at 45days and come later on as the plant matures.

After all the seed, or plant in general will not be mature 25-35 days after pollination. (with no real pistols before day 10 to catch pollen, said seed if pollinated would only be 25-35 days old in a 45 day trial)

And no bud is mature at 45 days.

What if these wanted metabolites brought on by UV are still unknown, and not thc an cbd as they tested.

a little off track . But Im sure, or wonder if there is an unknown genetic trigger that changes the plants progression or production of compounds knowing it has been pollinated. The change of focusing on seed production and NOW protecting them. Since its in "seed protecting mode" now producing these secondary compounds in higher concentrations knowing it has to protect the seed.

(one day i wonder if we will find out the plant produces different compounds pollinated, an now introduce said trigger to making the plant think its pollinated when in fact it is not)

now that i think about it, im not sure ive ever heard of secondary testing done for a seeded flower vs unseeded. and again, these unknown compounds other then thc and cbd

so much to type out. not enough time....

thanks for sharing

 

[Hiddenjems]

Why would it matter that they used blurple?

Because that high of light intensity with other common indoor light sources can bleach or cook plants.

 

[Corpselover Fat]

CA++ for years ive felt that UV ligh is important for terp & trichome production.

So good to see some new data suggesting UV's usefulness

The study produced no such data.

 

[Corpselover Fat]

Because that high of light intensity with other common indoor light sources can bleach or cook plants.

Are you implying we should use blurples so plants can absorb more light and photosynthesize more?

 

[Cerathule]

How would you know white would have grown double? Tests show they grow essentially the same as far as I know. Besides avaraging 500g/m² is not a low yield in my books and yielding the highest ammount possible per m² is not relevant to the study. Cost of the lights is also irrelevant to the study. I do not know why they used blurple... Maybe they had them. Maybe they used high efficacy blurples. It's irrelevant. Why did they not see diminishing results? Who knows. Maybe they took better care of the plants. Maybe it was because they did sea of green. Maybe it's because they used blurple, but if that was true it would open great possibilities (I highly doubt it though). More studies needed.

They do use RB in this fashion (mostly red, some blue) because many studies have shown that almost all plants can be grown with these 2 colours and there is furthermore a scientific law (for studies) in place that basically says that it makes sense to try and reduce the amount of variables used for a study down as much as possible. So if you can use just RB instead of RGB or white, then the setup with lower variables (RB) will be chosen. That's how science works. Furthermore, there are a boatload of photobiological studies that did use exactly this SPD - I'm sure many have seen it e.g. Bugbee does. Then there are also studies on the RB ratio itself. like 1:20, 1:10, 1:5 on photosynthesis rates. There's also studies about RB vs white whith an examination of the plant internal biochemistry. It also has to do with the ability of scientists to generalize.

 

[Cerathule]

Are you implying we should use blurples so plants can absorb more light and photosynthesize more?

Light interception happens at several dimensions, you have photosystems, chloroplasts, leaves and even the canopy as a whole. Many forget that and will just point out a single study and then claim a general statement. Like, if I measure oxygen evolution on an area of 1cm^2 on a single leaf somewhere at the top of a young plant in veg, with low PPFD like 150-250, I will see a higher rate with RB 1:10 than with RBG or added FRL. But if I take the same plant 4 weeks later and throw it in a closed container at 600-1000 PPFD and measure the whole canopy O2 evolution, the SPDs with added green or farred will now show better.
Alot of these results are just due to a studies setting, IMO it's better to try to understand the underlying mechanisms and then go for there. It's kind of sad so much nonsense/broscience is beeing interpreted into actually very valid empirical studies.

 

[Hiddenjems]

Are you implying we should use blurples so plants can absorb more light and photosynthesize more?

I’m saying a lot of the light put out by blurples doesn’t go towards photosynthesis.

 

[Corpselover Fat]

I’m saying a lot of the light put out by blurples doesn’t go towards photosynthesis.

Please do share if you have evidence.

 

[gmanwho]

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