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Grams Per Watt

It always seems to me that gram per watt needs one more variable to really be interpretable: days. Doing 1.0 GPW in 90 days from seed would be far more impressive than 180 days from seed, as it would cost half as much electricity.
 
You are exactly correct. The total hours of light and total cost, is the bottom line. It will be $ of electricity per gram that ultimately explains the most efficient method of growing, from a cost perspective. Then there is the Quality Perspective to consider.............................................

With this thread, I am trying to determine what is the best light for me. I use 600w MH/HPS for late veg and flower. There have been a couple mentioned that I will get more information on, but nothing has changed my mind yet.
 
Absolutely. I agree. That is why I indicated in my post that I had grown White Widow to get my numbers.

If I grow something like Wonder Woman that is noted for huge yields, I would expect to increase my grams per watt number, but not my skill as a grower.
 
Ok so im running 7 girls under a 315 an a 630, no idea what it's gonna yeild, previously with the 600 watt hps I was runnin, I think I got 7 ounces outta 6 plants, but also had alot of problems with heat stress from the lights an almost froze them when I hooked up my new fan so it wasn't to bad I guess lol an this last grow from 2 medium sized plants an 2 small small plants I yeilded like 6.5 also with the hps, the 7 that are going now have had the cmhs the whole time flowering so I'm excited to see how they turn out also since they haven't had any problems thus far (knock on wood) hopin for a good bit more this time.. buds have always been really airy an light.. hoping this will change now that I got more light in there
 
Morning 227, with your new lights, and the way you train your plants , with no problems, l don't think you will have any problems at all getting great results.
 
So now u got me doing math thanks I love it.

so I am going to use my pineapple express for this examle.

dry weight 105 grams
light 300 w led 136 w at the wall on for 62 days 24 hrs a day 1488hrs
136 x 1488 = 202 363 ÷ 1000 = 202.363 k watts of energy used

105 ÷ 202 = .52 grams per kilowatt hr

Energy cost 17 cents a kwhr

202 x 17 = 3434 ÷ 100 = 35 dollars for 105 grams of some of the best weed I have Eva smoked.

let me know if my math is off
 
Heck no, I ain't checking all that, but thank you for the complete picture. This is information that serious growers should know about their own setup.
 
This only accounts for the light I have an exhaust fan a circulation fan and air pump that needs to go into that calculation to get a tru picture of what is really costs.
 
Ok, I started growing in February of this year and I have harvested 5 times. Here are my results in order of harvest with multiple light variations over that time. All plants were grown in Coco with GH Trio nutrients and gpw is calculated using true wattage.

1st harvest-3 Auto-flower plants, 2-60 day Wonder and 1 Cheese. 56.4 grams using 2-300w GalaxyHydro led= .20 gpw.

2nd harvest- 4 photoperiod clones, 3 Girl Scout Cookie, 1 Cannatonic. 84.6 grams using 2-400w Roleadro COB = .21 gpw.

3rd harvest-1 GSC, 1 Cannatonic, 1 OG Kush. 280 grams using 1-600w Viparspectra and 2-300w GalaxyHydro = .51 gpw.

4th harvest-1 GSC and 1 OG Kush. 253.5 grams using 600w viparspectra/veg switch only for veg and 2-400w COB for flower= .63 gpw.

5th harvest-3 Snow White. 282.2 grams using 600w viparspectra/veg switch only for veg and 3-300w led for flower = .69 gpw.

My sixth grow grow is in week 6 of flower under 3-300w leds. 1 OG Kush and 1 Snow White, each in 5 gal. Bubble buckets with a 5 gal. reservoir outside the tent. I’m hoping to get to .75 gpw for this grow.

When end I first started growing I thought more plants under more light would get me better yields. I have since learned fewer plants with the right amount of light filling my canopy gives me the best results. I just pulled the trigger on a 315 cmh that I will be using for my next grow. I’m hoping to pull the same or more yield at 90 fewer watts.
 
Last harvest was coco with topping, LST and Scrog. 291g includes 45g of popcorn buds. My light is a California Light Works SS440 LED with 320w at the wall in bloom mode. .9 gpw if including the popcorn bud. .76 gpw. Of course, half the grow was in veg mode at 220w at the wall. And, I have room for one more plant, so I could add another 110 g or so if I wanted to manage 4 photos instead of 4. So, lots of variables for sure.
 
I am not prepared to start paying 3 dollars per watt for a light that will probably be obsolete in 2 years. It's just too rich for my blood.
 
You can just see the learning curve. Every new grower should see these results and the continuous improvement.
 
I would go with the .9. By the time they get used, all those popcorn buds will be good to have. Exceptional results.
 
If you're referring to the upfront cost, it more than pays itself off within the first harvest based on electricity cost. Running 4 only increases my bill $20. My buddies electric bill was ridiculous when he was growing with HPS. However, he was growing a few more plants than me lol.

All that said, I understand you aren't interested in them, so I will stop talking about them. Hope you find the light that is right for you!
 
Leds are amazing lights but u dnt get the same yeild as hps but u can buy cheap leds for under 300bucks I use bestva leds and a freind of mine uses vipraspectra and we both get amazing results the only issue with leds is there watts arnt true there a gimic for sales u need to find the true watts of the light my 1000w bestva actualy only draws 200watts from the wall. That needs to be takein into account. Plus leds are like lazer beams 90percent of there usuable energy only gets pointed down so u need a lot more lights for a coverage area. But u are right ur energy cost is lower but the cost per light is a lot more watt per watt. I use 200,350w leds for 1 plant and it could use more even when I keep my light at 4-5inchs away. Just some thoughts
 
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