I know the target yield is ussaully 1 gram per watt, but that is assuming HID lighting... I am in week 3 of flowering with my 250w HPS, when the ballast died. Not feeling like dumping the money into another ballast I used 276 watts of CFLs. What is a good yield with CFLs? think .5 per watt is reasonable?
What I think, this is pretty f***ed up way to calculate your yield. If read some lighting threads closely, the number of watts IS NOT related to gram or any unit of weight, it is a unit of power in a light bulb. What matters, is color temperature, it's colour spectre, lumens etc, which IS related to watts.
i see grams/watt a lot crookone its used to see how effective your grow is by measuring yield (total number of grams harvested from the grow) divided by watts (total wattage used to light your grow, also a measure of how much enery was used) SO, you get a measure of efficiency. Grams yielded / energy used. It doesnt take into account nutes, ph, ventilation, temps, a whole bunch of shit, but its NOT suppost to. This method lets you ballpark your performance. Obviously potency will play a factor too getting 2oz from 1000w wouldnt be considered a great yield no matter how potent it is, so you have the gram/watt test to see where you stack up
Ok, I see your point, measuring out the watt/gram after the harvest for energy usage, but you can't have a crystal ball to calculate your yield depending on the watts, that you have, before the harvest.
Started out with 3 plants under a 400 watt hps. 2 were male therefore my yield is alot less. How many plants is a main factor for that calculation
Beings as electricity is the single most expensive part of my grow I regularly use the gram per watt ratio in calculating my efficiency. My 3000w / 50 plant flat garden generally does just a little better than .5 grams per watt with yeilds in the 3-4 lbs range. My 3000w /75 plant vertical garden does much better with a consistent .75 grams per watt ... and twice I have hit the 1 gram per watt goal with 6.5 lb harvests.