Dialed in! 2x4 tent 1000w

Well,the fact that certain wavelengths are only effective and at their fullest spectrum at certain lengths/heights certainly throws an Italic "i" in the equation...
Hang em high.

1truAfghan said:

So you see...am I really running 108,000 lumens or is it more like 45,000? I'd say measurements taken at canopy are far more accurate than those taken at the the bulb, or 12 inches from source. Or even worse...the box the bulb came in.

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What are you using to measure? Sounds to me like an issue of not comparing apples to apples here.

Your measurement is in oranges and you look at the the chart depicting apples to see where you fall. The charts are based on output of the bulb. You have an issue with your measurement method or a very poor setup wasting 50% of your light.

Lumens as measured = oranges
lumens output by bulb = apples

Have you tried measuring light? Do you know the proper way?
I have a light meter that measures in lux and fc. I zip the door open just enough for my hand and meter to slip through. I place my meter where I want to take a measurement and allow it to measure for a min and settle then I record the reading. I do this at a few points on the canopy and come up with an average. This gives me a better idea of what amount of lumens are actually REACHING my plants. Not what the lumens reading of the bulb is.

It's basic lumen depreciation based on inverse square law. Lumen output is reduced to 1/4 value every twelve inches.
100,000 lumens at 12" is 100,000.
100,000 lumens at 24" is 25,000 lumens
100,000 lumens at 36" is 6,250 lumens
And so on and so on.
This makes sense that my 108,000 lumens at 16" is measuring 45,000 ish lumens. Making sense?

Here's a look at the tent.

And if you refer to jonjon's attachment which is one of the most commonly viewed charts online my measurement of lumens is almost exact. Based on wattages and distance from bulbs. So really...I'm right where I want to be...5,500 lumens/PSF.

1truAfghan said:

It's basic lumen depreciation based on inverse square law. Lumen output is reduced to 1/4 value every twelve inches.
100,000 lumens at 12" is 100,000.
100,000 lumens at 24" is 25,000 lumens
100,000 lumens at 36" is 6,250 lumens
And so on and so on.
This makes sense that my 108,000 lumens at 16" is measuring 45,000 ish lumens. Making sense?

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Look at the good scale. At the canopy you want to be in the 5000-8000 range without CO2. Over 8000 you need CO2 for benefit.

lumens per sqft are measured from the bulb. It's simply the total lumens output divided by the sqft of the area. It's an apples to oranges comparison measuring at any distance then doing the math.

I'm very curious to see how it works out, but I don't predict a stellar result. I would be disappointed if you let us change your mind. Lets see how it looks at the end, then we will know if you went as far overboard as I think you did.

I predict 400g or less and a harsh taste.

I am not so sure. Seems to me that the bulb rating for Lumen output is relative to the bulb not the area it will be used in (which would be measure by L/SF in order to determine the amount of actual light in a given area.)

nomofatum said:

lumens per sqft are measured from the bulb. It's simply the total lumens output divided by the sqft of the area. It's an apples to oranges comparison measuring at any distance then doing the math.

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If this were true it would render the inverse square law as it pertains to lumen depreciation invalid!

Oh I'm sure its a bit overboard. But not as much as you may think. I wish I could figure out a way to post pics so I could show you how it's been doing SO FAR this grow...

1truAfghan said:

I am not so sure. Seems to me that the bulb rating for Lumen output is relative to the bulb not the area it will be used in (which would be measure by L/SF in order to determine the amount of actual light in a given area.)

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You adjust the height of your lights to match the plants. The lumens/sqft is a way to size the system to produce the lumens needed. Then you adjust height to keep the canopy in the sweet spot. If you go vertical you add side lighting to keep everything in the sweet spot. It's about trying to get as close to 7500 lm to the nugs as possible, or more if you add CO2.

If part of your plant is getting blasted by more than 20,000 lumens it is in for a harsh life without the addition of CO2 and humidity.

Also note that we reduce the impact of the inverse square law by adding reflectors to the walls.

Are u saying 7500 lumens per square foot. Or at any given point? What unit of measurement are you referring to? Perhaps in missing something. But I haven't had a problem yet...so far, excellent results. The damn...upload a file...button doesn't work! Lmao

1truAfghan said:

Are u saying 7500 lumens per square foot. Or at any given point? What unit of measurement are you referring to? Perhaps in missing something. But I haven't had a problem yet...so far, excellent results. The damn...upload a file...button doesn't work! Lmao

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Those scales are dividing the total lumens by the sqft of the circle they would project on the floor at that distance. The ideal number without CO2 is about 7500. So just the 600 HPS would be ideal at about 23-24" from the canopy. At 23.5" it projects a circle of about 12 sqft and should measure 7500lm at the plant surface or 7500 lumens per sqft.

The inverse square law isn't about how light weakens at distance, it's about how light weakens as it spreads out. We block this after light has reach the wall, making the law only applicable to the distance from the bulb to the wall half way between the mid-canopy and the bulb. That is ignoring reflector loss.

So youre saying a 600 w hps at 24" from bulb is OPTIMAL lighting for a 12 sq ft area or a 4ft x 3ft area with ACERAGE co2 concentrations?
I could see how this would be SUFFICIENT for a decent yield and quality but I doubt it's optimal...do you have any source you could provide to prove the basis of the information?

1truAfghan said:

So youre saying a 600 w hps at 24" from bulb is OPTIMAL lighting for a 12 sq ft area or a 4ft x 3ft area with ACERAGE co2 concentrations?
I could see how this would be SUFFICIENT for a decent yield and quality but I doubt it's optimal...do you have any source you could provide to prove the basis of the information?

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At that distance you would have less than ideal spread, the middle would be substantially higher than 7500, the outside would be less. You would actually be better putting it higher up and taking the reflector loss for better distribution. With single big lights distribution becomes the bitch.

It's not optimal spectrum either, just optimum level, add in cool and UVB light and hit the same lumens/sqft for optimal spectrum and intensity. But you seem to have specturm well covered, you just seem confused on intensity level desired.

Well sir I guess I can see it both ways. I just feel that a 12 sq ft would be a bit underlit with the lumen output and distribution of a single 600w. But that's not to say i haven't seen people get excellent results with it.
However I am having EXCELLENT results with the lumen output and distribution of this set up as well. When I can figure out how to post pics I will.

I will say tho by in taking from outdoors my co2 concentrations should be higher than normal indoor intake. Perhaps it helps. I certainly see the balance you're referring too tho.

What you are doing is like an experiment on what it would be like growing cannabis on Venus after terraforming.

If you are getting good results now, I have a feeling if you add CO2 you will be giddy with the results.