Yields at differant PPFD?

Trippyness

Trippyness

Well-Known Member
Hello all.

Here is a question that has plagued me for a while.

Just as an example Ill use a 5 x 5 grow space.

Lighting would be COBS.

What would the difference from say 600,700 and 800 PPFD in yield.

I have seen some people get 1.5-2gpw if you still count like that with 600PPFD.
Obviously experienced growers which is what I am talking here. No newbie runs.

Would like to see if there is a major difference in yield in the same environment, sample plant count, same clones etc.

Just seems that the jump from 600 to 800 may not make as much of a difference that I have though and may be able to lower Electric, but again I may be wrong.

Just would love to see some real world results as opposed to numbers.
Preferred COB grows.

Seems like this may be interesting to get going.
Plus, how much ppfd is needed until we are disinishing returns and the rest comes down to grow and plant numbers? Sure 800PPFD is what we aim for , but who is to day 600 is not where we need to be at with good grower experience.

Trippy
 
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W

WeedBulbs

Member
Hi Trippy and All,

Trippyness said:
Here is a question that has plagued me for a while.

Just as an example Ill use a 5 x 5 grow space.

Lighting would be COBS.

What would the difference from say 600,700 and 800 PPFD in yield.

I have seen some people get 1.5-2gpw if you still count like that with 600PPFD.
Obviously experienced growers which is what I am talking here. No newbie runs.

Would like to see if there is a major difference in yield in the same environment, sample plant count, same clones etc.

Just seems that the jump from 600 to 800 may not make as much of a difference that I have though and may be able to lower Electric, but again I may be wrong.

Just would love to see some real world results as opposed to numbers.
Preferred COB grows.

Seems like this may be interesting to get going.

Trippy
Click to expand...
While your thoughts are logical... "you want to do an apples to apples comparison of various manufacturers at various PPFD in the real world", there is no simple way to do this using manufacturer supplied PPFD because:

PPFD IS A "SPOT MEASUREMENT"
To have something meaningful you need an "average" PPFD. For instance, if you have a 5' x 5' grow space, then take PPFD spot measurements on a 6" grid and then average those measurements.

USING PPFD ALONE IS NOT COMPARABLE
To illustrate this... an extreme (but common) example comparison is to compare high pressure sodium (HPS) to a targeted spectrum LED (ie mostly red with 10% blue). If both have an "average" 600 PPFD in an otherwise identical setup, then the LED system is going to have a buttload more gpw than the HPS system. In very simple terms, this is because the HPS spectrum has a high percentage of green light and green light over above 24% is ignored (reflected) by plants (this is why plants are green).

So to summarize... to have meaningful comparison you need "average" PPFD and the spectral distribution "percentages".

THEORY
This chart indicates that you get about a 15% bump going from 600 to 800...
http://www.tastyled.com/v/vspfiles/assets/images/PPFDvs-growth.png
This is very comparable to other charts I have seen. But as you have surmised, theory is likely to be much different than real world.

REAL WORLD
If anyone is interested in doing real world research on comparing lamps, fixtures, PPFD, spectrums and more, then I can discuss reimbursing a big percentage of your expenses. Send me a direct message if you are interested.
 
captainmorgan

captainmorgan

Well-Known Member
The nice thing about COB builds is you can match your PPFD to your grow style and environment. If heat is a issue you can go max efficiency and a 500 to 600 PPFD with a scrog and get amazing results. If heat is no problem and you want to grow medium sized plants use 600 to 800 PPFD and bigger plants 800 and up. My top 3 concerns are budget,environment and grow style when building a light.
 
Trippyness

Trippyness

Well-Known Member
WeedBulbs said:
Hi Trippy and All,



While your thoughts are logical... "you want to do an apples to apples comparison of various manufacturers at various PPFD in the real world", there is no simple way to do this using manufacturer supplied PPFD because:

PPFD IS A "SPOT MEASUREMENT"
To have something meaningful you need an "average" PPFD. For instance, if you have a 5' x 5' grow space, then take PPFD spot measurements on a 6" grid and then average those measurements.

USING PPFD ALONE IS NOT COMPARABLE
To illustrate this... an extreme (but common) example comparison is to compare high pressure sodium (HPS) to a targeted spectrum LED (ie mostly red with 10% blue). If both have an "average" 600 PPFD in an otherwise identical setup, then the LED system is going to have a buttload more gpw than the HPS system. In very simple terms, this is because the HPS spectrum has a high percentage of green light and green light over above 24% is ignored (reflected) by plants (this is why plants are green).

So to summarize... to have meaningful comparison you need "average" PPFD and the spectral distribution "percentages".

THEORY
This chart indicates that you get about a 15% bump going from 600 to 800...
http://www.tastyled.com/v/vspfiles/assets/images/PPFDvs-growth.png
This is very comparable to other charts I have seen. But as you have surmised, theory is likely to be much different than real world.

REAL WORLD
If anyone is interested in doing real world research on comparing lamps, fixtures, PPFD, spectrums and more, then I can discuss reimbursing a big percentage of your expenses. Send me a direct message if you are interested.
Click to expand...
Understandable, was mainly speaking Cree CXB3590 and Vero29
 
Trippyness

Trippyness

Well-Known Member
captainmorgan said:
The nice thing about COB builds is you can match your PPFD to your grow style and environment. If heat is a issue you can go max efficiency and a 500 to 600 PPFD with a scrog and get amazing results. If heat is no problem and you want to grow medium sized plants use 600 to 800 PPFD and bigger plants 800 and up. My top 3 concerns are budget,environment and grow style when building a light.
Click to expand...
Myself as well. Budget is a factor. I run SCROG and really am wondering how much in the REAL world yields vary from 600-800ppfd with cree or vero cobs. Planning a build and if I dont need 800ppfd to get max yield than I will. I currently get 2lbs from a 3 x 3 running 9 plants in 3 gal coco. Thats with blurple, 30 day veg. In a 5 x 5 I can see some serious yields. Just trying to get an understanding on which to choose. I am aware that after 800ppfd you are dimishing returns. But as I said real world and numbers dont always coincide.
 
C

churchhaze

Well-Known Member
@Rahz has done a few experiments with different PPFD levels. From what I remember, he suggested in the past that 800umol*s^-1*m^-2 got approximately the same g/W as 600umol*s^-1*m^-2.

FYI, i know almost everyone on RIU does it, but using PPFD as a unit is like saying you drive 80 speed on the highway rather than 80 miles/h or km/h. It's possible (but very unlikely) that a different unit is used for PPFD, like umol*s^-1*ft^-2.

I'm not trying to say everyone should be putting the units in every time, but it would make sense to reorder it as "speed is 80" rather than "is 80 speed". The plant would be "getting a PPFD of 800" rather than "getting 800 PPFD".
 
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Abiqua

Abiqua

Well-Known Member
I have a cut of Juicy Fruit that will yield 2 grams from low intensity all day long....

I also have cuts with cookie / Chem lineage and they choke on such low intensity and aren't that great under more either.

Strain dependent. Run each one a year or more, then start asking the questions. Shit will be revealed. :peace:
 
Rahz

Rahz

Well-Known Member
churchhaze said:
@Rahz has done a few experiments with different PPFD levels. From what I remember, he suggested in the past that 800umol*s^-1*m^-2 got approximately the same g/W as 600umol*s^-1*m^-2.
Click to expand...
Yes, I haven't noticed any GPW increase at lower photon density, 500 compared to 730 and 770 using cuts from the same mother. Not totally scientific but if there was a big difference I think I would have noticed. No confidence the yield curve follows the vegetative curve.
 
Trippyness

Trippyness

Well-Known Member
Rahz said:
Yes, I haven't noticed any GPW increase at lower photon density, 500 compared to 730 and 770 using cuts from the same mother. Not totally scientific but if there was a big difference I think I would have noticed. No confidence the yield curve follows the vegetative curve.
Click to expand...
This was the answer I was looking for. My main point is genetics and veg time. What PPFD would you reccomend ? 500,600,700,800. If going for same yield as high ppfd. Im currently look at around 600PPFD to the plant seems to be ideal. Any input would be helpful. I just dont see 800ppfd increasing yields much if at all. Any input would be great.
 
Trippyness

Trippyness

Well-Known Member
Abiqua said:
I have a cut of Juicy Fruit that will yield 2 grams from low intensity all day long....

I also have cuts with cookie / Chem lineage and they choke on such low intensity and aren't that great under more either.

Strain dependent. Run each one a year or more, then start asking the questions. Shit will be revealed. :peace:
Click to expand...
I currently run Blue Dream, a really good pheno I have. Mainly interested in ppfd and which is optimal and why.
 
Trippyness

Trippyness

Well-Known Member
churchhaze said:
@Rahz has done a few experiments with different PPFD levels. From what I remember, he suggested in the past that 800umol*s^-1*m^-2 got approximately the same g/W as 600umol*s^-1*m^-2.

FYI, i know almost everyone on RIU does it, but using PPFD as a unit is like saying you drive 80 speed on the highway rather than 80 miles/h or km/h. It's possible (but very unlikely) that a different unit is used for PPFD, like umol*s^-1*ft^-2.

I'm not trying to say everyone should be putting the units in every time, but it would make sense to reorder it as "speed is 80" rather than "is 80 speed". The plant would be "getting a PPFD of 800" rather than "getting 800 PPFD".
Click to expand...
Indeed, good observation. Any idea why people are using 800PPFD instead of lower? Seems like A waste for any good grower with good genetics to go past 600ppfd. Just a waste of energy and money.
 
guod

guod

Well-Known Member
churchhaze said:
FYI, i know almost everyone on RIU does it, but using PPFD as a unit is like saying you drive 80 speed on the highway rather than 80 miles/h or km/h. It's possible (but very unlikely) that a different unit is used for PPFD, like umol*s^-1*ft^-2.
Click to expand...
science is meters, seconds, grams not feet, yards or pounds
The metric system is an internationally agreed decimalsystem of measurement.

"The metric system has been officially sanctioned for use in the United States since 1866, but the US remains the only industrialised country that has not adopted the metric system as its official system of measurement."
https://en.wikipedia.org/wiki/Metric_system

same shit here /only one example of many/
Herbal_Essence said:

0.1ma 1.758625w 71.92265% :o

thank you so much for the info!
seems It would make sense to dim down to ~0.5ma (or till I hit ~900ppfd) @~66%
Click to expand...


1 Amp =1000 mA
0.1 Amp = 100 mA

0.1 mA = 0,000 001 Amp

uwrlrz5.jpg



 
Rahz

Rahz

Well-Known Member
Trippyness said:
This was the answer I was looking for. My main point is genetics and veg time. What PPFD would you reccomend ? 500,600,700,800. If going for same yield as high ppfd. Im currently look at around 600PPFD to the plant seems to be ideal. Any input would be helpful. I just dont see 800ppfd increasing yields much if at all. Any input would be great.
Click to expand...
There will be a point where GPW starts to suffer, but I don't think 800 PPFD is unreasonable. What does seem consistent is about 4 GPPW give or take depending on strain, keeping in mind the range I mentioned. If you can do 700-800 go for it.
 
C

churchhaze

Well-Known Member
guod said:
science is meters, seconds, grams not feet, yards or pounds
The metric system is an internationally agreed decimalsystem of measurement.

"The metric system has been officially sanctioned for use in the United States since 1866, but the US remains the only industrialised country that has not adopted the metric system as its official system of measurement."
https://en.wikipedia.org/wiki/Metric_system

same shit here /only one example of many/


1 Amp =1000 mA
0.1 Amp = 100 mA

0.1 mA = 0,000 001 Amp

View attachment 3666573
Click to expand...
You're totally missing the point. Look at the last paragraph of my post. Even if metric is implied, "PFFD" is not a unit so it shouldn't come after the number. You don't drive at "80 speed", you drive at a "speed of 80".

I am not "180 weight", "I weigh 180".

It's poor use of the English language.
 
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Trippyness

Trippyness

Well-Known Member
Rahz said:
There will be a point where GPW starts to suffer, but I don't think 800 PPFD is unreasonable. What does seem consistent is about 4 GPPW give or take depending on strain, keeping in mind the range I mentioned. If you can do 700-800 go for it.
Click to expand...
My main question was that if yield is not effected say on a 600PPFD or 800PPFD than what is the point of the extra light?
Im not a cheap person, but conservative. Real world results mean more to me than hypothetical numbers.
Mainly planning a Vero29 build or CXB build and wondering the yield difference if I go from 600 to 800ppfd. Seems like wasted light. I run large numbers of plants in 3 gallon coco. I pull 2lbs from 9 Blue Dream in 3 gallon Coco under Blurple. in a 3 x 3 tent.
 
C

churchhaze

Well-Known Member
Yeah, people in the US don't know how to use the metric system... It's just so hard to figure out. (sarcasm).

@guod ,in the US, almost all science classes use the metric system exclusively. Even most car manufacturers in the US use metric for almost everything now. It seems like you're trying to imply that people in the US are dumb for not abandoning the old standards, but the reality is that most Americans are familiar with both systems while Europeans are only familiar with one. I guess people in europe have a hard time with fractions.
 
C

churchhaze

Well-Known Member
We want to divide 10 units by 3 people... Each person gets 3.3333333 repeating units.

Wouldn't it be great if humans were born with 12 fingers? Then if there were 10 units, each person would get 4.(because 10 would be 12)
 
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