My dream lamp

I've been using about 45 watts per foot, and while I'm happy with the results so far it's got me thinking about the relationship between watts per foot and GPW. I have inquired and looked around a bit and think yield might be increased by spreading the light out a bit thinner. 25 watts per foot has been suggested.

At that level 1000 watts would illuminate 40 square feet, or a 5x8' area. That's 15 square feet more than a common 1000watt 5x5 HPS grow. The yield per foot would decrease, but would the overall yield increase over the same wattage at 45 watts per foot?

I would likely go with the Vero 18 again, 33 of them mounted to a frame using passive heat sinks. I like the Vero 18 because at 30 watts they can be placed close together giving an even light distribution and thus shorter distances between the lamp output and the individual buds. Using passive heat removal is a bit more expensive but it avoids the multitude of fans and replacing fans over the years.

As far as Kelvins, I've noticed people suggesting 3500 and even 4000. My combo setup averages out to around 3300K. I've noticed minimal stretch over several strains and based on that consideration I've actually considered using all 3000K emitters as I wouldn't mind a bit more stretch if I continue scrog.

So yes, my dream lamp is 5x8' putting out 1000 watts, I'm just not sure on the specifics yet. It could be a year or two before I build it so I've got plenty of time to ponder. What would you do with 1000 watts of LED?

You'll be spreading yield. Lots more smaller, harder to trim, nugs.

That's true. Most discussion seems to be about quality rather than quantity when considering watts per foot. It's a complex subject and there doesn't seem to be a definitive 'sweet spot', though there would be a point of diminishing returns on both the high end and the low end. Assuming an efficiency of 120-135 lumens per watt perhaps 30 watts per foot? 35? 40? Or is it all a trade off?

I think we're all still looking for that sweet spot. I'm going to be doing something similar with vero 18 but in a much smaller area.

I thought similar to you. The vero 29 is too intense. At 1.4A, you have to keep it far from the canopy to get even coverage. Vero 29 would be way better if designed to be 1 foot away from the canopy, and even then, the outsides are getting light at only 60 degrees at 50% of the intensity of the middle..

churchhaze said:

I think we're all still looking for that sweet spot. I'm going to be doing something similar with vero 18 but in a much smaller area.

I thought similar to you. The vero 29 is too intense. At 1.4A, you have to keep it far from the canopy to get even coverage. Vero 29 would be way better if designed to be 1 foot away from the canopy, and even then, the outsides are getting light at only 60 degrees at 50% of the intensity of the middle..

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I think Mr.flux has the right idea with his build. Utilizing softly driven vero 10's gives great coverage and allows for easy intermingling of monochrome led's. Really inexpensive to get adequate coverage compared to the bigger CXA and vero chips.

Rahz said:

That's true. Most discussion seems to be about quality rather than quantity when considering watts per foot. It's a complex subject and there doesn't seem to be a definitive 'sweet spot',

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I've observed some strains like more watts per sqft than others and can tolerate growing right up to a 1000 watt air cooled hood.

Yea, I have a buddy that uses HID and have noticed that too. There's still got to be some general area where the sweet spot is though. The only way to answer that question would be across multiple strains using similar lamps -w- emitter spacing variances. It's not something I will/can do, though building a new lamp with similar output would provide some interesting results. My current beast is 720 watts from Vero18s providing 45 watts per foot. A 720 watt lamp using Vero13s would have a different thermal profile, but on a 5x5' frame it's 29 watts per foot would be the largest change in variables.

Rahz said:

I've been using about 45 watts per foot, and while I'm happy with the results so far it's got me thinking about the relationship between watts per foot and GPW. I have inquired and looked around a bit and think yield might be increased by spreading the light out a bit thinner. 25 watts per foot has been suggested.

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What are you running 45 watts sq ft of?........(hps, Led, CMH) It matters.

At that level 1000 watts would illuminate 40 square feet, or a 5x8' area. That's 15 square feet more than a common 1000watt 5x5 HPS grow. The yield per foot would decrease, but would the overall yield increase over the same wattage at 45 watts per foot?

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At the moment 27 watts of cxa3070 3k ab bin works at least as well as 40 watts sq ft of Elite agrow's in cycloptics luminairs. I only have 1 harvest to go by...but....great weight......better smell and seems to be frostier too.

I would likely go with the Vero 18 again, 33 of them mounted to a frame using passive heat sinks. I like the Vero 18 because at 30 watts they can be placed close together giving an even light distribution and thus shorter distances between the lamp output and the individual buds. Using passive heat removal is a bit more expensive but it avoids the multitude of fans and replacing fans over the years.

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At the moment I'm running 3070's at 1400ma. There are 16 of them and they are spaced approximately 1.5 feet apart.

As far as Kelvins, I've noticed people suggesting 3500 and even 4000. My combo setup averages out to around 3300K. I've noticed minimal stretch over several strains and based on that consideration I've actually considered using all 3000K emitters as I wouldn't mind a bit more stretch if I continue scrog.

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Knna wrote that 3000k is the Goldy Lox spectrum.......and I would tend to agree.

So yes, my dream lamp is 5x8' putting out 1000 watts, I'm just not sure on the specifics yet. It could be a year or two before I build it so I've got plenty of time to ponder. What would you do with 1000 watts of LED?

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IMHO.......Over such a large space.....the concept of it being one lamp is counter productive. It makes the system difficult to work on and it is much easier to engineer and source/pay for parts if it is broken up into as many fixtures as necessary to meet with cost/budget and availability of parts.

I'm almost at 1kw of leds and the only thing that I could wish for is higher bin leds.

The high bin CXA 3070's 3000k's are king right now and I'm not sure if it's the goldie locks spectrum or the raw power through efficiency but I think a beginner could get over a gram per watt with these.

What are you running 45 watts sq ft of?........(hps, Led, CMH) It matters.

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Why, LED of course. I'm currently using 23 Vero 18's @ 1.05a over about 15 square feet.

At the moment 27 watts of cxa3070 3k ab bin works at least as well as 40 watts sq ft of Elite agrow's in cycloptics luminairs. I only have 1 harvest to go by...but....great weight......better smell and seems to be frostier too.

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Good data but I'm most curious about LED vs LED comparisons.

Knna wrote that 3000k is the Goldy Lox spectrum.......and I would tend to agree.

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I was thinking the same for LEDs but there are some 3500 and higher fans on the message board. My main issue at 3300K has been reduced stretch (compared with 3000K CFL) in early flower which affects my scrog. Has proven to be an issue over three strains. Growing sog perhaps higher color temps could be an advantage. There's been the suggestion that higher CT gives better quality product at a somewhat lower yield.

IMHO.......Over such a large space.....the concept of it being one lamp is counter productive.

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Excellent point. My lamp is 50lbs+. Some type of modular rack would be a better option than a single panel.

Right now I'm 43W/sqft. When I expand to the 4x4 adding the CXAs to the A51 lights it will be close to 42. No doubt it increases yield and I don't know about making more small buds.... My shit tightened up and the buds got larger.Was around 24W/sq at first.

Cool so you've done grows with 24 watts per foot and 43 watts per foot. Can you comment on the GPW between the two? Any difference in smoke quality if you've done same strains?

43 watts per sq ft is very near the "ideal" HPS wattage of 50.

50 for hps is the minimal recommendation. I always preferred 75+. Even still it doesn't matter led will produce more per watt. So even if the wattage matched the hps, the hps would lose in the yield department. I just pulled a lb with 345w led fairly effortlessly, no co2 either. And I'm not the only one with those kinds of results. I think that speaks for itself.

With 24 I pulled just under 1gpw. With the current just pulled 1.3gpw.

With 24 I pulled just under 1gpw. With the current just pulled 1.3gpw.

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That's good data. Not what I was hoping to hear but it bodes well for my current setup.

captainmorgan said:

The high bin CXA 3070's 3000k's are king right now and I'm not sure if it's the goldie locks spectrum or the raw power through efficiency but I think a beginner could get over a gram per watt with these.

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Any chance these are available thru the forums? Bin AB would be awesome.

Thanks