I suggested a topic based series of discussion threads a while back so I thought I'd start one.

Introduction:
Let's talk about... is an easy informal discussion format. Somebody starts a thread with the LTA subject line and the subject they want to learn about or share information on. Feel free to start one too!

Yield is quite complicated like "Hydroponics" so we can branch it off, as needed. I hope that we can all agree on a standard so that we make grow reports we can say "hey joe's grow did better than mine, maybe I should try his XYZ method."


So LTA yield.

Every one of us would prefer a yield with higher numbers to lower (given the choice) but there are so many ways of reporting yield and so may variables that it's hard to agree on an accurate way to judge one grow to another.

LTA different ways to measure yield and discuss what the pros vs cons are; I'll start with a few. We'll talk about increasing yield later...

Total weight:
Well, more is better in most cases but just because "joe" has enough resources to plant 10x times the space but it doesn't mean his method couldn't improve his yield.

Total weight (dry)/ per plant:
Giant trees are great (trust me ) because you have fewer plants but they take up much more light and more space but, like total weight, the biggest plant may not be the best method for various reasons.

Grams/per watt:
This is often used in the HID community but best suited for comparing equal (very similar) grows. Ranges of .5g/w for the newer growers is pretty good and 1+g/w is a decent goal for experienced and well tuned systems. The down side is all of the variables in veg/flower times, genetics, environment make it hard to calculate a figure that can compare all grows. I think implies that all available area is properly covered by a given light.

Grams/per Sq Foot (or meter):
I see seed company's use this to describe yield sometimes. There are ways to maximize in this measurement, double or triple stacked SOG in a high roof grow room would help you here but hurt you in the g/plant and g/$ methods.

Dollars/per gram (or g/$):
Take how much you spend on everything and divide it by yearly yield in grams. Outdoors wins this with no need for lights, however, some indoor methods are clearly more expensive than others.

I've used g/w for a while but it's only really good for comparing my next grow to my last one, if you get my drift. I think that a newer method that takes more factors into consideration might be better.

What do you all think?

I forgot about this one. Good meds...

As I was saying in another thread: "I know g/w doesn't take into account veg wattages and veg time but you can take the total dry harvest and figure out what your yearly total would be and then you would be able to compare that to other grow styles, like SOG, if you try that in the future. If it takes you 4 months to clone/veg/flower then you get 3 harvests per year, with a 3 month cycle you get 4 per year. With SOG you might get 5 or 6 smaller harvests per year but you get the point. I think yearly averages are better comparisons for total yield. I guess, then, you'd need to divide the total cost of production (water, nutrients, power, media etc) by grams to get a cost per gram to grow. The cost of durable equipment (like lights, fans, tents, etc) would have to be divided by 10-15 years and added to the yearly cost. I think then we'd have a better estimation of how much different methodologies truly cost."

There are a lot of variables but I don't think you can get more fair than average yield divided by cost. It's keeping track of all of the expenses accurately and completely that's hardest.

OK, the reason that I ended up here is that I'd like to make a decision about the lights that I am testing. For me this is a big money decision. Ideally, I think that 2000 watts of nominal LED power should produce the same or better yield than an equal wattage of HID lights, in my case it is actually 2400 watts of HID. If LED can produce equivalent or better PAR value light as HID, then I would assume ( I know) that yields under each would be fairly equal. These questions come up for me because of my physical room dimensions, and other growing parameters which I am not (cannot) going to change. Testing one 800 watt LED doesn't answer or justify the added expense of making up the difference in wattages. Going from 800 to 2000 watts Solar Storm LED equals additional investment of nearly $3000.00. Hence a big money investment.

This maybe a little premature, I'm only in week 5 of flower, and the pudding is not finished yet. I'd like to stick to one measure, gpw. So, I guess that bud and keif is what will go into my weight calculations in building a yardstick. Hopefully, the folks at CLW can come up with a plan, for those of us who help to prove the product, to help us keep the farm.

ROCK ON!

From my experience with HID and from what I've seen of LED grows so far, I'd say that 2000W of LED would yield about the same as 2000w of HID and the only savings, if any, would be based on not having to replace HID bulbs and even that assumes that the LED doesn't have any problems with diodes, drivers or fans. The cost of LED is partly why HID is still king. A 1000w HPS will penetrate better than ANY LED on the market today and the cost to buy is so cheap that you can buy the light (ballast and hood), a 10 year supply of bulbs and a 6" fan for cooling the HID...for cheaper than 1 LED light.

Par for LED, like lumens for HID, is is mostly marketing hype. It is a form of measurement but it doesn't indicate growing potential when comparing 2 different lights. For example, according to many LED manufacturers the PAR value of a much smaller LED (300-700w) is supposed to be equal to a 1000w HID (you see these comparisons all of the time) but, in reality, yield tells another story. If a 620w LED was comparable to a 1000w HID you'd have to yield over 1.7g/w and the best we've seen here, so far, is .87g/w. HV's grow may hit 1g/w but that would only put the yield about the same as a 600w HID, nowhere near a 1000w HID as the marketing PAR values would suggest.

Since we're talking about the SS 800w, I should mention that it doesn't put out 800w, only about 620w of LED (in flower, less for veg settings) and little more from the T8 fluorescents. So, if we assume that the 620w SS LED is about the same as as a 600w HID (even though nobody here has yielded that much yet) and you were wanting to compete with 2000+w of HID you'd need to buy 3 or 4 SS lights at 2000.00 each, retail. Now you said 2400w HID which could be many combinations; 2x 1000w + 1x400w or 4 x 600w, etc. Personally, I'd go with 2x 1000w for flower + 1 x 600w for veg but that's just me. My cost on all 3 lights + fans + bulbs would still be less than the LED purchase.

Typically, g/w is just flowers but the amount of keif you'd be able to add with 1 SS is almost nothing so you can throw that in if you want but most people don't include that in g/w measurements.

I'm not sure a pure g/w measurement is the best method for comparing different grows for a number of reasons but it's pretty close. Regardless of other factors we know that a 1000w HPS light CAN flower over 1g/w. I've yet to see that with LED.

I think when lights are discussed, led vs hid in particular, somehow the cost of electricity should be factored in.... total $$$ per gram is worth looking as much or more then gram per watt.... just a thought

TXStorm wrote:I think when lights are discussed, led vs hid in particular, somehow the cost of electricity should be factored in.... total $$$ per gram is worth looking as much or more then gram per watt.... just a thought

If the grow only gets around 1g/w the cost for electricity is the same no matter which light you use. For example, 600w LED vs 600w HID; they both use the same amount of electricity. Where cost becomes a factor is when you add the cost of the equipment. Some costs are repeating (like soil/nutrients, etc), every grow, some costs should be averaged over the life of the equipment, like lights, fans, chillers and other items that will last for years.

I agree that g/w is not all inclusive of the cost of growing but g/w is pretty close (not perfect) when determining how much yield a light will produce in flower and comparing that to other known lights.

One more thing, if you really look at the numbers, a 1000w HPS can produce around a pound + of good marijuana, which equals 448 grams, that does not actually equal 1g/watt, more like .5g/watt, and a 600w HPS produces around .5 + lbs average. I have averaged with my 357 Magnum (@180 watts) 5.5 oz's, which is .85g/watt. Realistically, I think that efficiency really goes to LED when it comes down to grams/watt.

Your numbers are wrong. More than 1g/w is completely possible and experienced HID growers often pass that 1g/w mark.

Sorry but facts are facts, look it up...

Whoever told you that a 1000w HPS will only grow 1 pound isn't much of a grower, you should slap that fool.

So, the topic of yield came up in another journal and before it gets out of control I thought it best to move that debate back to here...

First:
I do believe that the CLW SS series of lights will eventually hit the 1g/w mark but I doubt that it'll ever go much more than that until we see more powerful diodes.

That said:
1g/w is very possible with HID and that isn't even the limit. Try a yahoo search for "1.2 grams per watt" and if that not enough for you try the same yahoo (I hate google and bing) search for "1.5 grams per watt" and you'll find the following posted in another forum that will not be linked here on these forums.

"Any 1.5+ grams per Watt grows????

"Google Heath Robinson or do a search for him on IC, he did that SEVERAL times and is somewhat of a pot (folk) hero around here, or at least to me he is a hero. Check out Bobble's Aerohead's, Whodare and Marlo's grow journals you'll see peeps getting that OR pretty damn close to it."

"Yup check out Heath, I also know someone that got 2.3 G/pw from his last run he was running a V-SOG. clone's only had 3 day's veg. It's a KILLER system. 1.5 G/pw was the highest I ever achieved, still trying to get up there again , maybe this run."


Now that 2.3g/w (quoted) is hearsay but I've seen other journals that claimed 1.9g/w. Some people refused to believe that 1.9g/w, claiming that it was exaggerated, but even if it was only 1.5g/w that's still over 3 pounds per 1000w HPS and I've never seen a believable LED journal that even hit the 1g/w mark.


Discuss...