Co2 during flowering


Well-Known Member
energy usage per gram of dry weight.

More plainly put, is 2gpw at 4kw avg consumption per grow better than 1.3/5gpw with 2kW avg consumption?
To begin with, "Grams per Watt" is a nonsensical measure of performance. It is literally nonsense, it could mean anything or nothing.

One can use 100 Watts of power for a year, and then harvest 300 g, which is an impressive 3g/W, but in reality this would be a joke, considering it took you a year of time and about 875 kWh of energy to harvest 300g.

You correctly use the word "energy", but you talk about "average consumption per grow", which would be average power draw per grow, and then the duration of the grow would have to be specified in order to get to total energy used.

Power draw (in Watts) is irrelevant, only total energy usage (in Watt hours) is meaningful.

It would make sense to talk about "Grams per Watt HOUR", i.e. g/Wh, if we want to ignore grow area (let's assume space is never the issue). This then also takes into account how long the grow lasted.

Also, if you're not concerned about energy usage (maybe you've got excess solar power or something), then "Grams per day" are interesting.

What's completely uninteresting, but the only measure that ever get mentioned is "Grams per Watt". It's a complete bro measure if there ever has been one.

Example: 300 W lighting, 2 months veg (18/6), 3 months flower (12/12) requires ~650 kWh of energy. How much do you want to harvest for this to be a "good yield"? 300g sounds nice ("1 Gram per Watt"), but you've spent 5 months of time, which does not appear in the g/W measure.
300g would give you 0.46 g/kWh (and 2g/day).

Now compare to 100 W lighting, autoflower 3 months to harvest (18/6) requires ~162 kWh of energy. Let's assume we harvest 75g, that's only "0.75 Grams per Watt", but 0.46 g/kWh like above. In this case it's 0.83g/day.