@Northern_Loki Summed That Shit Up. 
excellent job!!!
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Excellent! Im very glad we got past my snarky attempts at humor and have progressed to having a good discussion. 
What he said!
Thanks for backing me up.
I still dont agree watts is in any way useful as a metric for comparison - even with those givens.
The problem is you dont know where your grow/plants fall on Bugbeeâs graph - which is a small portion of the crude one I posted.
If your grow happens to be on the low end of the DLI scale as far as getting the optimum number of photons to the plant, then adding more âwattsâ (with all of your givens) would increase the yield - but you would have no way to know how much.
If your grow happens to be near the peak efficiency point as far as DLI, then changing âwattsâ up or down would have no effect on yield.
If your grow happens to be too hi on the DLI, then adding more âwattsâ would actually lower yield, and lowering the watts would increase the yield.
I dont see any value to using something as a metric when you have no idea if changes are a positive or negative or nothing. Even if you can guess if the delta is plus, minus or zero, you have no idea how much it would be.
Plus there is still the problem of defining the watts to begin with - Mars Hydro âwattsâ or someone elseâs label watts vrs wall watts, etc etc?
That all adds up to g/watt equaling an imaginary number
Whew!!! I am so glad we are all finally on the same page on that one! 
Anyone want to go back to what metric we might use that maybe has at least a tiny bit of value? I have changed my mind a bit on some things, but wont bother if no one is interested.
Itâs partly due to something I noticed on Bugbeeâs graph and was reinforced by something @Northern_Loki said about DLI that I had forgotten.
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Forgot about your post - sorry.
Yeah, that goes back to what @LemonadeJoe mentioned about it and the use of KWH. Costs were a big factor for larger grows. Plus, LEDâs were just coming on line and there was all that stuff about efficiency, watts in vrs watts out, etc. All of that focused a lot of attention on lights and somehow watts got singled out.
I think the main thing that got lost in the details somewhere was that total cost should be referenced to total yield. It should have been a g/$$ ratio they were looking at. In fact thats what any business should be focused on - not watts. Gram/watt tells you nothing about the cost per gram, and thats the bottom line. Even using g/kwh doesnt cover all the costs, and any business will want to include all costs. If you are a commercial grower, lights will only be some fraction of total costs. Rent, taxes, labor, AC, insurance etc etc will add up to a lot more than light operating costs.
real question here⌠WHYYY really try to see how much bud or flower is generating by the light if the light source is not growing only bud??? , where is the rest of the biomass of the plant , i think biomass is part of the yield,is not âusableâ but was generated by the plant, some people just weight final buds and even those buds have stems that you will not smoke and is part of the biomass of the plant, i say yield is 100 percent the biomass of the plant, then it comes on how much of the biomass was really usable, and different strains will vary ridiculously, just my 2 cents hereâŚ
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It has nothing to do with cost⌠its to do with limited power draw⌠you guys with the micro grows probaly donât understand
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Correct. It makes zero difference to me if I spend $20 or $22 dollars a month on power.
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thats not really feasibleâŚcan you see a grower taking the time to dry and cure a entire plant to get a total weight ? or would a grower just separate the valuable aspects of the crop and weight that ?
at the end of the day grams per watt winsâŚ
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Ask anyone, what is your DLI and PPFD at any one point in time? How did they measure it? What happens when they flip to flower?
If they have an answer, Iâd imagine theyâd also have a meter and perhaps have a bit OCD or a fancy automated set-up. Itâs an expense, can be difficult to use correctly, takes time, and is a barrier towards data collection. Not practical for many. Not worth the added effort for others.
Ignoring what is capable in practice for many is going to be a non-starter. Most folk donât have the sophisticated gear and set-up to be able to create any of the metrics / data that would be useful for a scientific comparison. In fact, even if some have the ability to accurately measure PPFD, youâd still be missing some of the other key measurements thatâll also directly impact your grow and, for that matter, how closely you could mirror the Bugbee results. So, most end-up estimating or using measurements found from the manufacturerâs datasheet or found on the web. This is the best that can be done under the circumstances and should not be dismissed out of hand. That is not optimal but, as here, saying itâs not accurate is also ignoring the reality of the situation.
As far as matching Bugbeeâs graphs, this should be considered a generalization to get you closer to an optimal situation. Very much like VPD targets, weâre talking hand grenades not precision unless you have precisely the same conditions as his grow chambers along with the same genetics, etc. And, for that matter, equipment with similar accuracy. What his work, along with others, tells us is that there is a point of saturation. It is probably somewhere around xxxx for this genotype/phenotype under these particular conditions. You get general targets and a understanding that it existsâŚsomewhere around this amount. Digging deeper youâll discover why it occurs and how it can and does change.
If you want to truly determine saturation/photochemical quenching along with many of the other photosynthetic parameters, youâll need something like the PhotosynQ + a good PAR meter. Then add all of the other environmental metrics including CO2. Itâs awesome but also impractical for most.
What can be done is educating individuals on the pitfalls of using âWattsâ so that others can understand what it means outside of their personal grow experience. Expecting precision is not practical for most. All we can do, as observers, is parse and interpret results by making estimations under limited information. 1000W chinesium fixture at 18 inches, weâll thatâs probably 200 PPFD. A 600W Heliospectra at 18 inches, weâll thatâs probably 500-600 PPFD at the canopy. Expecting folk to not use âWattsâ when nothing else is available to them isnât going to be practical. You are correct with what youâre saying, I just donât know what applies to the majority.
What is shareable is whatever information is available. Run what you brung. Then thoughtfully apply, with care, what learning is provided in discussion to make a generalized assessment that might be of use in comparison.
Going scientific and reproducible is a whole 'nother ball of wax. That would be my preference but, hey, we only do what we can with what we have.
Relative, as described, has a specific contextual meaning. âWattsâ are not changing. You are doing the exact same thing regarding the lighting while manipulating something else in your system causing a change in âgâ. Perfectly acceptable relative metric for your use. It will not be applicable as an accurate comparison, as is, anywhere else but it can still provide valuable insight towards improving how you grow as a base metric.
Without the tools, change your lights and you can no longer make certain conclusions by using the past âWattsâ information. But you can still make certain valid conclusions. Understanding what conclusions are valid is where a discussion, such as this one, provides valuable insight in what to consider, whatâs sensible, and which information is useful to share.
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I think I have figured it out! Larry3215 as an individual has no use for watts 
Iâm hoarding all the watts measurements to myselfâŚthanks 
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I am at a legit 2 grams per watt of dried primo bud !
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is that better than your last run?
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no⌠my last run 4032 grams of dried bud with 2000 rated watts
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Iâve⌠done thingsâŚlike teach people to grow. You can do it formulaic like, do this, wait this time, do that, etc right up until harvest. Growing is quite simple, really. But then⌠those people want to âtry something elseâ in the cycle. OK you want to explore, thatâs good. But then⌠they never get a baseline and never measure weights and never figure out if that thing they did improved, made it the same, or lowered their yield.
They will do what they call an âexperimentâ where they have 4 plants and they are going to add âmagical ingredientâ the grow store owner sold them on for 100$âŚâitâll get you three grams per watt!!â unsubstantiated claim from the dude. So thenâŚinstead of giving one of the plants the âmagical ingredientâ or even 3 and leaving one as the control group. They dose them all with âmagic powderâ then when they get a yield in the end⌠theyâre like ohh this is the best shit in the universeâŚman! Then they form a bond with âmagic powderâ and if you say that was a useless waste of money they say your full of shit. I mean, I am saying âmagic powderâ but when I say that you can insert any unsubstantiated claim. Then I remind them that I am âNULL HYPOTHESISâ and their âmagic powderâ doesnât do shit, unless they can prove it. SomehowâŚlikeâŚpeople can live their lives like that??? Itâs the most astounding thing about humans!
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well within margins. Due to the limits of the universe, you will never get exactly the same measurements. I give er the olâ significant figures treatment. Youâd be worried if it dropped to 1-.5 grams per watt⌠thatâs outside acceptable ranges.
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Exactly.
But to take that even further if a friend and I are running the same light then he comes over and says he yielded half what I did I think thatâs a clear indicator that their grow methods are flawed somewhere. It doesnât pinpoint a problem, but it does give you a clear indicator that they are doing SOMETHING wrong.
Saying itâs a useless metric is a bit over the top. This feels like the âflushingâ argument that has gone on forever. Youâre saying itâs useless but only in the case you are presenting â it doesnât invalidate the numerous other ways that the metric IS useful.
When I stop paying per watt, Iâll stop caring. Until then watts is the primary factor in âgrams yielded per dollar spentâ.
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Ugh. I didnt die even though I wanted to a couple of times, but Im still way under the weather, so this will have to wait. Dang kidney stones suck worse the g/watt.
I know all you folks cant wait for me to keep beating this horse, but hold your horses a little longer.
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you got large kidney stones the alpha blockers wonât handle?
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Feel better, dont worry the horse will still be dead when you get back to beating it. 
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I make them like they were free candy. The last batch I had to have surgically removed with the lazer was 8 stones the size of almonds and another 6 or 8 ranging down to 3mm or so. It took three surgeryâs to get them all zapped. The real kicker that topped off almost a year of constant pain was the urologist left tons of what he called âdebrisâ. Turns out that was a crap ton of stone pieces many of which were still several mm in size and very jagged and rough. Those are a bitch to pass. Im on some dam pill three times a day now, but it hasnt stopped the stones - or Im still passing left overs from last December. I think its some of both. The new stones are relatively smooth, and easier to pass, but the old ones are still really rough.
LOL!
Sorry man, Im going to pick on you first because you left the door wide open and that makes it the easy one.
Just to return the comment - saying you are paying âper wattâ is a bit over the top 
I dont know how you can be paying by watt. You bill is based on KWH - which has TIME as a critical part of it. The âwattsâ in that bill also have nothing to do with the watts on the label of your light. Those watts are the wall draw during the time the light was on. The âwattsâ on the label have nothing to do with that.
Well, unless your lights are always on for the exact same length of time on every grow at the exact same output at all times - for veg and flower - AND - you always veg for the exact same number of hours total and flower for the exact same number of total hours - all at the exact same output âwattsâ - on every single grow.
So, no your costs are not based on or in any way directly connected to the label on your light fixture. You have to do a lot more math based on completely different measurements to get to cost.
Darn it @Northern_Loki. We had almost all the nails driven into the g/watt coffin, but you had to go and leave the head of the last nail sticking up by one single micron.
I think we could easily come up with a better choice than watts. We have already talked about several that would be far far better. Actually, almost anything would be better than watts on the label. Cats or outlets are just as valid Seriously.
I noticed that Dr Bugbee is using canopy area in sq meters. That seems to me to be a far far better metric to use. Its still not perfect - for one thing, its subject to a potential fudging by the individual doing the measurements, but it is at least directly linked to total grams. If you increase/decrease the sq meters of canopy, you can probably count on a corresponding increase or decrease in grams. Increasing/decreasing the number of âwattsâ printed on a label has no measurable or even guessable connection to the grams.
If its valid to use something arbitrary (like the marketing number printed on a label) that is ânot changingâ as a metric, then how is g/watt better or in any way different from g/outlet or g/cat? I would imagine the number of outlets in your tent doesnt change either and I dont change the number of cats in my grows very often
Can you give some examples of valuable info you get based on the watts on the label of your light? I still dont get it, but if Im missing something here, I am happy to be corrected.
The label on your light doesnt tell you your cost or what the actual energy delivered to your plants is. On top of that, you can never have everything exactly the same from one grow to the next. The veg times will be different, the flower times will be different, the over all length of the grow will be different, and the distance to the canopy will be different. ALL of which means the effective DLI will be different - and in no way connected to the label on the light.
Not trying to be snarky at all, but seriously - how is using a number probably chosen by someone in the marketing department, printed on the side of the fixture, any better than using cats?
Im ok with leaving the last nail out of the coffin if you can show me how thats valid.
Back out the other way and take PPFD and convert it into Watts. Itâs possible but not enjoyable. Problem statements for the use of either Watts or PPFD was discussed.
One could certainly correlate watts to grams. And, it can also be predictive. You could also correlate it to cats but that clearly conveys much less useful information.
Heck, I could predict right at this moment a relative change in the g to watts with a change in wattsâŚbecause I have good characterization information available. I have the curves for W to PPFD across a variety of heights for my fixtures in my room. And, I could predict that itâll follow the same general curves as the PPFD curves generated by Bugebee.
I have the equipment to create the characterization, though, without having to resort to a bunch of intermediate calculation.
For an individual thatâs just tweaking the dimmer and looking at the kill-a-watt, they can also make a predictive assessment based on their relative scenario. Itâll have a similar curve but with a different scale while being fully applicable to their experimentation. That still has use. Discovery can be applied to different situations, the scale would change but the trends would have a similar flavor. If they do not, then a piece of information is missing and needs to be interpreted.
If there was no correlation, we should just turn off our lamps and weâd be good to go.
Watts is time based. Specifically, it is tied to the second and is defined as joules per second (W). KWH is directly correlated but it is in hours as opposed to seconds along with the decimal point change.
Youâre kind-of ignoring what was said and are rather trying to develop a metric that can be freely shared across different conditions without any work to interpret the results. Youâre not going to get that without a whole lot of other information including how many cats you have running your grow op.
Watts in, PS efficiency, LED efficacy, LED operating curves. You can estimate the PPF from Watts without a meter (then with more work PPFD). In fact, going backwards is how a fixtures efficacy and efficiency can be determined experimentally. Like anything, garbage in / garbage out though. Which applies to any type of measurement including PPFD and the utilization of inaccurate marketing data.
Realistic expectations in practice are important. The single most important part of a discussion, such as this, is in providing an understanding of what folk are looking at and what has been presented. Whether thatâs PPFD or Watts. Both require an understanding of what they mean in order to be able to meaningfully interpret and utilize the information along with understanding the limitations. Both can provide useful information. One is better but requires tools. While the other requires more work to glean useful data. Sharing the latter outside of their context should raise an eyebrow when applied elsewhere with an informed individual asking the ârightâ questions to form a conclusion. Itâs possible but many times some key piece is missing or inaccurate to be able to make a comparative assessment outside of the relative context.
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