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Grams Per Day: Determining Cannabis Yield Success by Weight

InTheShed

Member of the Year: 2018 - Member of the Month: Jan 2018, Nov 2018 - Grow Journal of the Month: Aug 2018 - Plant of the Month: Oct 2018
So see if I have this correct. I am running two 315W CMH's, so that is 630W. That is 0.63 of 1000.
So my formula would read, Yield / 0.63 / Days = G/day.
686/0.63/63 = 17.3 gram/day.
Is this correct?
GR
The problem you're having with the math is that it doesn't work with fractions of a light. If you divide by .63 you get a bigger number than if you divided by >=1. You would have to multiply it there to get a smaller number.
686*0.63/63 = 6.86 G/L/D.
 
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Marzbadrock

Plant of the Month: Sept 2015 - Nug of the Month: Jan 2016, May 2018
This is like the lady at home depot telling me a 16 in by 16 in tile was 1.5 sq ft
 

Marzbadrock

Plant of the Month: Sept 2015 - Nug of the Month: Jan 2016, May 2018
The problem you're having with the math is that it doesn't work with fractions of a light. If you divide by .63 you get a bigger number than if you divided by >=1. You would have to multiply it there to get a smaller number.
686*0.63/63 = 6.86 G/L/D.
Hey sorry everyone ! I really wasn't trying to cause a ruckus. I wasn't trying to disagree with the per light , per watt nothing like that. I seen something that is wrong to me, let's just agree to disagree. Smoke a bowl n have goodnight everyone
 

Marzbadrock

Plant of the Month: Sept 2015 - Nug of the Month: Jan 2016, May 2018
I read an interesting article by Ben Burkhardt, who once owned the largest indoor grow facility in the country. He found that there was no simple metric for yield analysis which took into account not only the power used by lights but also the length of flowering time. Often yield is stated as grams per watt, but that doesn't take into account the difference between a plant that finishes in 45 day versus a plant that takes 90 days. He put forth a metric that takes both into account and works for the closet grower as well as a huge commercial grower, and returns a number that can be compared across any grow type.
The equation is as follows: Yield in grams ÷ number of 1000W lights ÷ days in flower = GPD average.
As an example, my three plants were under 1600W of leds and took an average of 90 days, and yielded 3000 grams of dry flowers.
3000g ÷ 1.6 ÷ 90days = 20.8 grams per day.

Here's a link if anyone would like to see the source material.
Grams Per Day by Ben Burkhardt.
Maybe rider can just clear something up for me so i know. Maybe I'm just missing something obvious.
20.8 per 1000w used?
33.3 grams a day for 1600w
 

gr865

Well-Known Member
@Marzbadrock

I believe it is call Extrapolation!
Example
20.8 is to 1000 W = X is to 1600 W. Just cross multiply and divide.

So 20.8 x 1600 = 1000 X so,
20.8 x 1600 equals 33,280 divided by 1000
So, X = 33.28

Not a math teacher so I hope this made sense.
 

Marzbadrock

Plant of the Month: Sept 2015 - Nug of the Month: Jan 2016, May 2018
Ok! So I read Ben Burkhardt article and this thread again. There's some things that are left out and some things that may be getting lost in translation. Let's come together n figure this out so we all can be on same page.
First thing I noticed is Ben is not saying grams per day per light at the end of his equation, and the equation is for gram per light per day.

Here's a clip from his article
In order to account for both the flowering time and the weight yielded from a particular batch, I developed a simple and useful system of data analysis of true yield results and trends. First, the number of 1,000-W lights used in the batch is determined. Then the total grams of dried manicured flowers and the days of flowering time are assessed. The equation is as follows: Yield in grams ÷ number of lights ÷ days in flower = GPD average.
Here’s an example: 1,000 grams yielded ÷ 1 light ÷ 70 days in flower = 14.29. So this single light’s crop had a gram per day (GPD) average of 14.29. No matter how large or small a crop is, it can be measured as such, allowing an equal playing field of crop analysis irrespective of crop size or time it takes to flower particular genotypes. Here’s another example from a larger batch: 58,453 grams yielded ÷ 75 lights ÷ 67 days in flower = equals 11.63 grams per day.

Let's look at his first example 1000grams ÷ 1 light÷ 70 days = 14.29 grams per light.
Does not matter if that was a 10 watt or 10,000watt he got 14.29 for that light

His last example. by his numbers he gets 11.63 grams per day? Pretty horrible off 75 lights lol.....obviously that's 11.63 per light per day even though it says grams per day.

So if we substitute a 500 watt light in his first equation for the 1000watt then the new equation going by what was posted earlier would be
1000grams ÷ .500 ÷ 70 ?

Doing this does not work, it doubles his grams per day.

The equation should be
1000grams ÷ 70 days= 14.285 gram per day
 

Marzbadrock

Plant of the Month: Sept 2015 - Nug of the Month: Jan 2016, May 2018
Yes I was in a sense. He posted he got 20.8 grams per day
He got 33.3
I was just clarifying that was 20.8 per 1000w
 

gr865

Well-Known Member
Yes I was in a sense. He posted he got 20.8 grams per day
He got 33.3
I was just clarifying that was 20.8 per 1000w
You stated above
"Let's look at his first example 1000grams ÷ 1 light÷ 70 days = 14.29 grams per light.
Does not matter if that was a 10 watt or 10,000watt he got 14.29 for that light"

If you reread the article, he states 1 light is 1000W.
 

Marzbadrock

Plant of the Month: Sept 2015 - Nug of the Month: Jan 2016, May 2018
So your using 650 watt if I remember right.
So that would be 1000÷ .63 ÷ 70
That's using his formula with your light.
That would mean he averaged 21.97 using your light?
 

Marzbadrock

Plant of the Month: Sept 2015 - Nug of the Month: Jan 2016, May 2018
Converting a watt to a decimal fuck the equation up.....it should be grams per day ÷ watts used.
So 1000÷70 = GPD ÷ watts = gram per watt.....right?
 
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