Yield from COB's

So again...no you don't. Nor do you even know of what the sun puts out. You have one "example" that doesn't even prove what you think it does.

All of that 2000 is with in the PAR spectrum and usable by plants.

I am quite familiar with that paper. And it talks about photosynthetic efficiencies...not useable absolutes.

If something issues light 40% relatively. Simple give it 40% of 100% won't make it student use all of that...it's still only going to use 40%.

So keep reading and actually understand it. Then actually outhit into practice.

So please cite the actual text, not a whole paper.

Even if was true that a maximum of 400umol/s/m2 is absorbed by the plants after all losses are taken into account, that doesn't mean that you should radiate them with only 400umol/s/m2. You'd still have all those losses and end up with much lower yield.

How much lights plants can use is very different between different types of plants and with the temperature.

You can buy devices to measure which light intensity is most efficiently used by the plants "on location". These things measure photosynthesis at different light levels and plot this so you can see what works best.

Pretty much like in that PDF although the Way and Yamori paper goes through different temperatures. Of course that's also a variable in photosynthesis. As is the CO2 level and amount of food in the water.

Greengenes707 said:

So again...no you don't. Nor do you even know of what the sun puts out. You have one "example" that doesn't even prove what you think it does.

All of that 2000 is with in the PAR spectrum and usable by plants.

I am quite failure with that paper. And it talks about photosynthetic efficiencies...not useable percentages.

If something issues light 40% relatively. Simple give it 40% of 100% won't make it student use all of that...it's still only going to use 40%.

So keep reading and actually understand it. Then actually outhit into practice.

So please cite the actual text, not a whole paper.

Click to expand...

Well feel free to ignore the information and go along your merry way. Just because you have been doing something wrong for years doesn't make it right. Advancement is made by those who challenge the status quo not those who ignorantly defend it.

As far as you know I am some random guy posting on a forum. As far as everyone knows you are someone who sells a lighting product and posts his grows on youtube. A lot of information from those videos and posts point out that you, self confessed I might add, have lots of areas to improve on.

Social status of an information source is irrelevant to correctness of the content.

Oh and to correct you, the 'Photosynthesis' text has the useable percentage listed on figure 1-2 in chapter 1-3. The paper from uwo has no mention of photosynthetic efficiencies so you might want to review them again. Reading doesn't necessarily mean comprehension.

PhotonFUD said:

Well feel free to ignore the information and go along your merry way. Just because you have been doing something wrong for years doesn't make it right. Advancement is made by those who challenge the status quo not those who ignorantly defend it.

As far as you know I am some random guy posting on a forum. As far as everyone knows you are someone who sells a lighting product and posts his grows on youtube. A lot of information from those videos and posts point out that you, self confessed I might add, have lots of areas to improve on.

Social status of an information source is irrelevant to correctness of the content.

Oh and to correct you, the 'Photosynthesis' text has the useable percentage listed on figure 1-2 in chapter 1-3. The paper from uwo has no mention of photosynthetic efficiencies so you might want to review them again. Reading doesn't necessarily mean comprehension.

Click to expand...

This is Yodaweeds other account. Just ignore him GG707

I'm not ignoring it. It doesn't show or support 400µmols being the ideal intensity for higher plants.

And yes, my point is that you some random guy with nothing backing him. You may be a bum with the internet or a PHD. But no matter who/what you are...with out wither your own experiments to show and validate your ideas, or a plant degree(which doesn't mean practicing grower) your a no body. So I don't understand why it is so hard to ask and get proof of something that DOESN'T sit inline with accepted concepts and actual use through out the world of plant growth.

I am not perfect, and never have I claimed to be. But the key is that I actually grow, and continue study the craft. I have accepted that I'm a shitty grower and only pull 1.5-1.8 units per 4x4 time after time. My loss you gain?? What ever helps you sleep.

No one is arguing uniformity is good and to strive for, and no one arguing that a more photosynthetically active spectrum between 2 same/similar sources of the same output is more ideal. But you keep saying those after trying to claim 40µmols.
Which might I add...neither of your example show/support that. And I'm not sure how your trying spin that I'm question those very basic concepts, then keep deflecting that 400µmols is not enough.

So to get back to you showing and proving something from "photosynthesis"...
Show efficiencies(%), not usable absolutes(hard values that are not dependent on being a % of the total)...

Just like I said, but you say I was wrong? That figure is talking about everything the sun puts out. Meaning the 2000µmols from the sun we measure is from the 47% is not being measured, and pre leaf interaction.
The figure uses energy so it doesn't translate directly to use on a photon bases, but it's close enough from concept illustration.
4255µmols(total from the sun)...2000µmols(known at leaf surface)÷.47(from outside 400-700nm)=4255µmols total output from the sun across gamma rays to radiowaves or what ever you want the "total range" to be, it's irrelevant, because we know we have 2000µmols at plant level within 400-700nm from the sun.

The rest of the figure shows the plant inefficiency. And that is not from too much light...it's from not efficient enough plants. They will always be that way. So if you supply them with 400µmols, they will still have the near same photosynthesis efficiency and only use ~10.6% of it.
4255µmols and only 5% finding it's way all the way to fixation. Meaning 212µmols was fully fixated(10.6% of the 2000µmols the leaf surface stated with).

I'm arguing that 400µmols like you have come into multiple threads to spew without any data backing it or personal experience. Show how you or who ever is deeming 400µmols the intensity and how you are getting there based on your references
So again..show some real practice of what you are preaching. Even someone else practicing it? Where are the real world results. Simple validation of your hypothesis.
I have over 5 years of documented grows supporting worthy gains up to 1000µmols regardless of tech. As well as confirming with others such as Gavita, my findings. Which is also supported by numerous scientific papers from McCree to Bugbee.

doz said:

This is Yodaweeds other account. Just ignore him GG707

Click to expand...

No its not I don't even know that guy stop tryin to start problems with me kid. I don't even know who you are or why you are sweating my nuts so hard but I don't really care about greengenes or you .

All the data is whatever, if it works for ya great if not change it, or not, your choice.

CoralMafia said:

All the data is whatever, if it works for ya great if not change it, or not, your choice.

Click to expand...

I have been saying that all along, whatever works best for you.

If you are interested in improving then you have to do your research and try new approaches. There is a good deal of useful information from universities that can help. All I have done is reference it so that each can make their own determinations. Basic knowledge sharing and challenging discussion. The community is what benefits.

It is understandable that some out there just won't be able to accept something different. Ignorance is the shield and sword of the foolish.

Apparently a vendor in this thread has a comprehension problem accepting bonafide research. Even when the information is explained, still isn't able to accept the findings of qualified researchers.

Maybe he has a learning disability, I don't know, but anyone who uses the term 'UL proof' in a youtube video is probably someone you shouldn't be buying electrical products from.

PhotonFUD said:

I have been saying that all along, whatever works best for you.

If you are interested in improving then you have to do your research and try new approaches. There is a good deal of useful information from universities that can help. All I have done is reference it so that each can make their own determinations. Basic knowledge sharing and challenging discussion. The community is what benefits.

It is understandable that some out there just won't be able to accept something different. Ignorance is the shield and sword of the foolish.

Apparently a vendor in this thread has a comprehension problem accepting bonafide research. Even when the information is explained, still isn't unable accept the findings of qualified researchers.

Maybe he has a learning disability, I don't know, but anyone who uses the term 'UL proof' in a youtube video is probably someone you shouldn't be buying electrical products from.

Click to expand...

Do you have a detailed documented grow at your 400µmols? If so can you link me or post the details here? By all means if I can yield the same with 400µmols as 1500+, I am all for it.

This thread has digressed

Interesting to note. I checked to see if my girls were root locked in the 7 gal pots. The roots actually didn't root any more at all! The root balls were still 2 gal in size

What happened there???

Here's my next go round. I have since dropped the lights another 6" as well.

doz said:

Do you have a detailed documented grow at your 400µmols? If so can you link me or post the details here? By all means if I can yield the same with 400µmols as 1500+, I am all for it.

Click to expand...

well in grams per watt it should yield more. in grams per square foot it will yield less.

CobKits said:

well in grams per watt it should yield more. in grams per square foot it will yield less.

Click to expand...

Well yield/area has many contributing factors, one being uniformity. If 80% of the plant was exposed to ~400 umoles that should provide better results per area than >800 umoles to only 20% of the plant.

The ~400 umoles, and everything else I am referencing is from available research that most people should be able to access with a little work. If anything, it should only be used as a starting point to get to the best radiant power as there are other factors to consider.

Light isn't really different than anything else to balance:

1. Find the saturation point of your plant. It could be 50 umoles (eg. Fern) or 400 umoles (sugar cane) but there will be an optimal level where there is not further increase in photosynthesis from additional light power.
2. Place emitters to balance available light power directly exposed to as many leaf surfaces as possible with the goal of meeting or exceeding the saturation point.

Plants can handle more light than they can use up to a point. If you can move underutilized light to areas of the plant that would make better use of the light it will improve efficiency. People are already showing improvements using vertical growing techniques as more areas of the plant are getting more overall light than only from the top. Side lighting also works well.

For more information, here is the PI (photosynthesis-irradiance) wiki stub that has some example charts and good information:

https://en.wikipedia.org/wiki/PI_curve

At least hemp is only a C3 plant....

Safehaven said:

This thread has digressed

Interesting to note. I checked to see if my girls were root locked in the 7 gal pots. The roots actually didn't root any more at all! The root balls were still 2 gal in size

What happened there???

Here's my next go round. I have since dropped the lights another 6" as well.

Click to expand...

You could easily add some brightstix/A19 just under the canopy for good luck

Nice work, plants should be happy. With that clean setup having great airflow, did you consider going with a fabric type pot instead of solid? That might help address the small root ball.

Air circulation along with humidity control are going to be your two best weapons on PM.

The last grow was with fabric pots. The roots simply just did not grow anymore after I transplanted them. Weird.

This time I didn't have fabric pots readily available, so I used the plastic ones.

PhotonFUD said:

You could easily add some brightstix/A19 just under the canopy for good luck

Nice work, plants should be happy. With that clean setup having great airflow, did you consider going with a fabric type pot instead of solid? That might help address the small root ball.

Air circulation along with humidity control are going to be your two best weapons on PM.

Click to expand...

PhotonFUD said:

The ~400 umoles, and everything else I am referencing is from available research that most people should be able to access with a little work.

Click to expand...

so it should be pretty easy to post a link here, then?

Safehaven said:

The last grow was with fabric pots. The roots simply just did not grow anymore after I transplanted them. Weird.

This time I didn't have fabric pots readily available, so I used the plastic ones.

Click to expand...

They do say to transplant couple of weeks before flip(as you know) to allow the root mass to fil out the pot. I always took that advice but never really believed the root system wouldn't continue to grow out some during flower. I have never risked experimenting with this so interesting to see the results of the root ball you noticed.
Set ups looking nice, look forward to seeing those nets fill out.

CobKits said:

so it should be pretty easy to post a link here, then?

Click to expand...

I have several times:

'Photosynthesis' by Hal, Rao published by Cambridge University Press.


http://www.doctortee.com/dsu/tiftickjian/plant-phys/ps-variations.html

How about that one, is it good enough? It the syllabus of a Biology course from an accredited university which happens to show a chart where the photosynthetic rate increase peaks ~400 umoles.


If bored and have a few hours to kill, this old thesis is relevant to the discussion as well:

https://open.library.ubc.ca/cIRcle/collections/ubctheses/831/items/1.0093242

Some other suggested reading:

http://photobiology.info/Brennan.htm

https://www.researchgate.net/publication/264671178_The_minimum_photon_requirement_for_photosynthesis

PhotonFUD said:

I have several times:

'Photosynthesis' by Hal, Rao published by Cambridge University Press.


http://www.doctortee.com/dsu/tiftickjian/plant-phys/ps-variations.html

How about that one, is it good enough? It the syllabus of a Biology course from an accredited university which happens to show a chart where the photosynthetic rate increase peaks ~400 umoles.


If bored and have a few hours to kill, this old thesis is relevant to the discussion as well:

https://open.library.ubc.ca/cIRcle/collections/ubctheses/831/items/1.0093242

Some other suggested reading:

http://photobiology.info/Brennan.htm

https://www.researchgate.net/publication/264671178_The_minimum_photon_requirement_for_photosynthesis

Click to expand...

Again, please post details of your grow with 400umoles.

doz said:

Again, please post details of your grow with 400umoles.

Click to expand...

Aside from the obvious possibility of easily falsifying any results, why would you not accept the results from the scientific community? After all they are qualified, funded, have the proper equipment and follow methods that are open to oversight by the entire community.

On the other hand you are asking for some random guy to post some random pictures of a random grow using whatever is claimed to be used by the random guy as validation.

My guess is that you stopped your education journey upon getting your high school completion. For many, intellectual pursuits are difficult and there is nothing wrong with that.