Imo this is how it rolls.. And I ain't the best grower either. I'm just an average grower with common sense.
Everybody talks of 1 gram per watt like it's a trip to the shops! I hardly ever get one gram per watt, though I have twice with leds from over 50 attempts. Imo that was down to outside temps being perfect, good humidity outside too which made the grows turn out great.
The rest of the time...
I constantly get between 0.5 grams per watt and 0.8 grams per watt. I'm happy with that. I have never got 1 gram per watt from hid lights anyway. I have used over 20 different led panels and have started growing with leds from go.
Recently I had 4-5 months of growing under hid lights. Grew some nice plants, which is nothing new to me. The quality of the buds was terrible compared to led, which is 'minimum' twice as frosty under led. Also hid buds were nowhere near as dense. Plus the stems are fatter under hid lights which accounts for lots of weight when being weighed, as very few dry their bud properly before working out their gpw stats.
I like to compare it this way, which was from my last grow. 600w hps cooltube... So, that's 650w actual draw from the ballast, so nobody should even be comparing the numbers 600w, as every 600w ballast draws at least 650w.
So that's 650w for a 600w lamp in a cool tube in my case last grow. The glass makes you lose 10% of the light, so now we are talking 650w draw for 540w of light. + 28w for the fan running my cooltube. So 650w + 28W is now 678w for 540w of light. Yes you can have it closer to the canopy if you want to lose overall coverage.
I now use 'what I consider a ball park comparison figure of led'
Budmaster 675 od which draws 380w on full power + 300 od that draws 180w on full power. So 560w actual draw. That's with a '28w' 5'' fan for extraction. So that set up is 588w actual draw from the wall.
I can also dim my set up without changing the spectrum, unlike hps. I can run both leds on half power on 280w which has the same par on half power as a 600w hps, yet draws about the same as a 250w hps. Which is 280w actual draw. Though will add here my coverage on half power is far, far, far superior to a 250w hid light and pisses all over it!
My extraction also runs very quiet under leds, so it doesn't sound like I'm in a factory, like it did with hps growing! It's as quiet as having a fish tank plugged in.
So for me, I get a little bit more yield of lesser quality bud under hps.
For Hps growers, time to re-calculate your grows using 650w instead of 600w. Anybody with less than 650 grams of buds, using a 600w hps has failed to hit 1 gram per watt. Lets no pretend it's 600w to make your stats better!
Plus plants grown under hps need 50w per sq.ft in flowering. Led plants don't, my 380w led covers way more area than a 400w hps by 25% with better results, so that means to me that leds need around 37.5w per sq.ft 'maximum', as the plants can use the light the leds give off unlike hid. What is it again, little rusty, 13% useable light isn't it from hps?
Plus my house insn't going to burn down if my extraction fails. That appeals to me quite a bit actually! The safety aspect, before greed kicks in, safety was no.1 for most of us when we set out!
This plant has been vegged on half power, so the exact draw of a 250w ballast... Say no more!
I have vegged under a 250 hps + a 250 mh and it just doesn't do this!
