Why GPW?

[GrowerGoneWild]

GPW is a lousy metric. It doesn't factor time into the calculation. GPkWh or grams / kilowatt hour is much better. I suggested using gram / unit of light / unit of time as a more pure metric as plants don't consume watts to grow they use photons. The devices that emit photons consume the watts.

GPkwH, is needlessly complicated for a simple peek at a yield Efficiency. More or less go 8-9 weeks as your time average.
If you gotta calculate photons, when plants only care about PAR what value is GPKwH?..

"The devices that emit photons consume the watts". Not true, a true GPW calc would include TOTAL wattage consumed. AC/Fans etc..

Use it for your own entertainment.. pretty sure it wont catch on.

 

[siftedunity]

GPW is a lousy metric. It doesn't factor time into the calculation. GPkWh or grams / kilowatt hour is much better. I suggested using gram / unit of light / unit of time as a more pure metric as plants don't consume watts to grow they use photons. The devices that emit photons consume the watts.

I do see where you are coming from but all you need to do is add in a time scale and your good for the gpw.

I personally use the 1gpw scale but I factor that in with 4 weeks veg and 9 weeks flowering. so that's my own scale. within that if anything it to slow in veg or doesn't yield enough for that veg time etc, it gets binned.. I do keep smaller yielders but I don't flower them as much.

so the standard should be something like gpw/per 4 weeks veg and whatever in flowering. its obvious if you are vegging out a plant for 10 weeks and then, flower for 12 weeks the gpw isn't really gonna be a clear indicator.

I noticed this a lot on forums. people will say something is a great yielder but then they veg it up for 3 months.

 

[timmur]

GPkwH, is needlessly complicated for a simple peek at a yield Efficiency.

"Needlessly" is debatable, but complicated it isn't!
Grams / kwH
kwH = total wattage * hours / 1000. Of course they do have online calculators if the math gets too deep!



I do admit that if you're comparing GPW with others who growing under very similar growth cycles that it is a quick and easy metric. I was really pointing out its weakness in a competitive business environment.

 

[Drek]

I think that GPW and GPKWH are different in what they (are attempting to) establish. GPW, afaik, attempts to make a connection between the size of the load(lamp) and the size of the product. GPKWH, while being totally valid, is different, in that it indicates(to me) growth over time.