GPW? Should we start focusing on GSQM instead?

Here is a quick recap for anyone that wants to give us an example
use this calculator for kWh
(or multiple hours x watts and divide by 1000)

What you need:
veg time (hours)
veg power (watts)
-calculate kWh
flower time (hours)
flower power (watts)
-calculate kWh
veg kWh + flower kWh = total kWh

Wet yield (grams)
(you could do dry, I dont see the point personally)

Area (square meters, google the conversion if you only know square feet)

Divide total grams by total kWh giving you a result of how many grams each kWh yields
and multiply by Area.
Or simply express it as
grams , kWh , square meters

example:
400 grams / 176.4 kWh = 2.27 grams per kWh
If I have 0.5 square meters that equals 1.13 grams per kWh per square meter.

After reading this, I have to agree with much of what wietefras has said.

Veg time doesn't matter, as it's directly related to the number of plants you grow.

More root mass = more yeild, which is why SOG systems (flowering individual clones with almost no veg time) works so well. A SOG will always outperform a single plant for any given footprint or lighting arrangement and with much less veg time.

There will be an optimum amount of light for any given space - it doesn't matter how much space you have, you are either under, over or correctly lighting it for any given strain. Outdoor farmers who calculate crop yields in terms of square space, for example, are usually growing under an optimum light source - the sun - and so yes, yield per square meter comparisons are certainly valid and a good metric.

What's more interesting (to me, anyway) is, if you are applying an optimum amount of light to any given space, how much energy are you using in providing that light? That is the real measurement of lighting efficiency.

Flowering time is a more important variable than veg time because, by and large, longer flowering plants produce higher yields. Roots continue to grow during flower. Taller plants provide a greater surface area for light to access and be converted to energy. Genetics most definitely plays a part, but given the same calyx-to-leaf ratio, the longer flowering plant should produce a higher yield.

Which leads me to a final point: footprint is only one metric. Vertical (or head) height also plays a part in yields if you are growing taller, longer flowering plants or providing side lighting. So why not calculate based on cubic meters instead of square meters (or feet)? After all, vertical HID lighting is more efficient than horizontal, reflector-based HID lighting.

I haven't touched on aeroponics vs media-based hydroponics vs soil vs soilless etc, but the success of each method simply applies to the correlation between root mass, yields and plant energy efficiency (how much energy is expended growing roots to uptake nutrient and moisture, and stems/leaves to access and process light).

In all, it doesn't surprise me in the least that wietefras got similar g/umol/s figures comparing HPS with LED - because plants can only use so much light!

Prawn Connery said:

Veg time doesn't matter, as it's directly related to the number of plants you grow.

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example , grow in a scrog, veg time is much longer with fewer plants + with all the training, uses more power, also creates larger yield for that area, yes it matters. I dont understand how veg time can be dismissed, it makes no sense to me. SOG, many more plants, much shorter veg time, still take it into account. I dont think anyone is arguing that some methods are more or less efficient than others, I am not. IN a SOG you have to have big mother to clone from, more area and power to keep them alive, gotta take that into account too imo.

Prawn Connery said:

So why not calculate based on cubic meters instead of square meters (or feet)?

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I pondered that the other day actually , m-3, then realized taller plants take more time to get that way, more time, more power. Didn't seem necessary as time and power consumption are being taken into account.

Vertical would be difficult to factor in yes. Still if you get higher g/W or g/m2 with that you will see that in those figures.

There is a huge database of yield results with all that data in it. Apart from kWh of course because no one actually knows how much watts their fans, pumps, drivers, AC's etc etc etc use. Still, it does mention days of flower wich would be a much more easily obtained and much more usable parameter anyway.

canadian1969 said:

example , grow in a scrog, veg time is much longer with all the training, uses more power, also creates larger yield for that area, yes it matters. I dont understand how veg time can be dismissed, it makes no sense to me.

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No it does not. You start flowering when the area is full. It does not matter how you got there.

If you want you could start a different benchmark for how long it takes to get to a full tent ready for flowering. Still, it's a completely useless metric to include in flowering performance.

canadian1969 said:

example , grow in a scrog, veg time is much longer with all the training, uses more power, also creates larger yield for that area, yes it matters. I dont understand how veg time can be dismissed, it makes no sense to me.

Click to expand...

SOG = "Sea of Green" technique. SCROG = "Screen of Green" technique. Two very different techniques with vastly different plant numbers and veg times (and yields, incidentally). Have a little read of the difference and I'm sure the penny will drop.

canadian1969 said:

I pondered that the other day actually , m-3, then realized taller plants take more time to get that way, more time, more power. Didn't seem necessary as time and power consumption are being taken into account.

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Not really. Again, once you grow a few indoor sativas, you'll know exactly what I'm talking about.

wietefras said:

No it does not. You start flowering when the area is full. It does not matter how you got there.

If you want you could start a different benchmark for how long it takes to get to a full tent ready for flowering. Still, it's a completely useless metric to include in flowering performance.

Click to expand...

It does matter because every tick of the clock uses electricity which impacts the overall efficiency/performance of the grow

Prawn Connery said:

SOG = "Sea of Green" technique. SCROG = "Screen of Green" technique. Two very different techniques with vastly different plant numbers and veg times (and yields, incidentally). Have a little read of the difference and I'm sure the penny will drop.



Not really. Again, once you grow a few indoor sativas, you'll know exactly what I'm talking about.

Click to expand...

I understand each method, the metric I am proposing doesn't care what or how you are growing, its simply taking time, energy use, yield and area all into account.

canadian1969 said:

I understand each method, the metric I am proposing doesn't care what or how you are growing, its simply taking time, energy use, yield and area all into account.

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Which means your numbers become less comparable (if not incomparable) to someone who vegs differently. Even when their flowering performance is identical. So you are putting a lot of effort in actually making things worse.

Why? What's the point?

Me: How much does a train ticket from Paris to Rome cost?
Canadian: Well how did you get to Paris? Did you fly from Canada or do you live in Paris. That makes a huge difference.
Me: Ehm what?

I am seriously starting to think you guys are afraid to run these numbers on your grows.

I don't agree that veg time can be negated by adding more plants to fill the canopy. You may fill the canopy in with less time with a greater number of smaller plants, but your plants won't be as tall and with as many total nodes as fewer plants that vegged longer. In general the SOG style may win in terms of yield over time, but vegging longer will definitely cause you to get bigger yields, and thus g/w for a given grow.

I don't see why you'd hide veg time from your results.. If you think that packing a smaller number of plants will get you the same yield in less veg time, you should do that, and then post your GPW and g/sqft.

churchhaze said:

I don't agree that veg time can be negated by adding more plants to fill the canopy. You may fill the canopy in with less time with a greater number of smaller plants, but your plants won't be as tall and with as many total nodes as fewer plants that vegged longer. In general the SOG style may win in terms of yield over time, but vegging longer will definitely cause you to get bigger yields, and thus g/w for a given grow.

I don't see why you'd hide veg time from your results.. If you think that packing a smaller number of plants will get you the same yield in less veg time, you should do that, and then post your GPW and g/sqft.

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Agreed.
I think they are just tag team trolling at this point,probably off on a strategy session atm, lol
just run the math yourself, post the results

churchhaze said:

I don't agree that veg time can be negated by adding more plants to fill the canopy. You may fill the canopy in with less time with a greater number of smaller plants, but your plants won't be as tall and with as many total nodes as fewer plants that vegged longer. In general the SOG style may win in terms of yield over time, but vegging longer will definitely cause you to get bigger yields, and thus g/w for a given grow.

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Unfortunately, this has proven to be incorrect.

Well I tried lots of plant numbers and I did get similar g/W and g/m2 results with anything from 4 to 25 plants per m2.

I have no clue how much watts I use during veg on a certain group of plants. I don't care either. It's in a different area and many plants can be bunched together in the veg tent which go to different flowering area's. Some take months to get from seed to flowering some are done in weeks. It's whatever it is depending on how quickly I want to get it done.

Flowering is a neatly boxed in period with an easily measurable outcome and input. That's why everybody uses that. There is a perfectly good reason for it. It's not just "chance" or lazyness

It's like when this idiotic idea up came to use reflectors on COBs because when you measure right below the COB you see a higher intensity (at the same height). Ignoring all kinds of negative effects from this change. People misunderstanding what is actually better is what leads to people wasting time and money on dumb ideas

Just think things through, why would anyone waste time on making these easily obtained metrics worse?

wietefras said:

Well I tried lots of plant numbers and I did get similar g/W and g/m2 results with anything from 5 to 25 plants per m2.

I have no clue how much watts I use during veg on a certain group of plants. I don't care either. It's in a different area and many plants can be bunched together in the veg tent which go to different flowering area's. Some take months to get from seed to flowering some are done in weeks. It's whatever it is depending on how quickly I want to get it done.

Flowering is a neatly boxed in period with an easily measurable outcome and input. That's why everybody uses that. There is a perfectly good reason for it. It's not just "chance" or lazyness

It's like when this idiotic idea up came to use reflectors on COBs because when you measure right below the COB you see a higher intensity (at the same height). Ignoring all kinds of negative effects from this change. People misunderstanding what is actually better is what leads to people wasting time and money on dumb ideas

Just think things through, why would anyone waste time on making these easily obtained metrics worse?

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If you dont care to take into account the whole of your processes energy use, thats fine, dont, but its not science.

canadian1969 said:

If you dont care to take into account the whole of your processes energy use, thats fine, dont, but its not science.

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Why not?

Everybody but you and church chooses to leave out the inconsequential and often immeasurable bit before they start flowering.

If anything, convolution your data with irrelevant parameters is not science.

But sure go post your numbers and compare them to church's and see how amazingly they match up. Or not

wietefras said:

Why not?

Everybody but you and church chooses to leave out the inconsequential and often immeasurable bit before they start flowering.

If anything, convolution your data with irrelevant parameters is not science.

But sure go post your numbers and compare them to church's and see how amazingly they match up. Or not

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Anything that consumes energy and time is not irrelevent. Just do the math, if you cant, stop arguing.

A proper sea of green would have a fuller area ready to flower with a shorter veg time yielding a higher gram per watt amount.

Less of the same plants in same area would take longer to veg to fill the space and likely yield the same so less grams per watt.

But again. Same yield per meter squared (or cubed I like that as I grow bushes not screens of colas.)

We hear only flowering numbers most times but professionals with commercial grows take all parameters into account for cost.

MichiganMedGrower said:

A proper sea of green would have a fuller area ready to flower with a shorter veg time yielding a higher gram per watt amount.

Less of the same plants in same area would take longer to veg to fill the space and likely yield the same so less grams per watt.

But again. Same yield per meter squared (or cubed I like that as I grow bushes not screens of colas.)

We hear only flowering numbers most times but professionals with commercial grows take all parameters into account for cost.

Click to expand...

I had the same thought about meters cubed, in Ontario for a legal personal grow we are being limited to 4 plants no taller than 1 meter so it might make sense to use m-3 , by comparison say a commercial grower who is doing stacked factory farming like the photo below, could use m-3 or multiply m-2 by the number of tiers. I am uncertain if there is an advantage to m-3



If anyone thinks those guys are only counting g/watt, you gotta get yer head checked. lol

canadian1969 said:

Anything that consumes energy and time is not irrelevent. Just do the math, if you cant, stop arguing.

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That's not how science works. You have to be able to explain how your idea is better than what everybody else is already using to good effect.

Besides I actually did provide arguments and you just contribute ... well nothing.

So explain what is the benefit of adding an almost random number of kWh to the cost of flowering when only flowering actually produces the yield? It can be anything between 75kWh and 250kWh (ie as much as a third to 100% of what I use for flowering), but the yield doesn't change.

Which means that instead of a reasonably stable 2g/kWh/m2 (between say 1.9 and 2.3) I now fluctuate between 1.1g/kWh/m2 and 1.7g/kWh/m2. Making it a completely incomparable metric.

Nothing changes on my flowering tent. No different lighting, same nutrients. Nothing changes in my annual yield. It's just whether I was keeping vegging plants alive waiting for a free flowering room (or if I threw them away and didn't use them) or if I use cuttings and push things through at max speed.

The price difference is only €40 per m2 even between those two huge extremes for a yield worth thousands per m2. So money wise I really don't care a rats ass. Logistics in keeping the flowering rooms occupied at 100% and producing at optimal levels is the only thing that produces yields. The rest is just overhead.

So that's the actual science of economics right there.