optimal watt / square foot or m2

Bolof · Nov 5, 2016

I ask for factual and polite answers for this question:

What is the optimal watt / Square foot or m2 given that you have a fixed amount of watts to spend.

For example. You have 1 000 watt for light. What Will give the highest yield:
- 1 m2 with 1 000 watt
- 1,5 m2 with 667 watt / m2
- 2 m2 with 500 watt / m2
- 3 m2 with 333 watt / m2

Ok. You understand the question. Based on your knowledge and experience. What is the optimal watt per m2 or Square foot.

majins · Nov 5, 2016

Watt isnt a very good measurement since different light sources will give different amount of light for the same power.

But 50W per sq ft seems to be what people aim for when I was researching the same question.

Porky101 · Nov 5, 2016

50w/ sq ft HPS
40W sq ft MH
30W/ sq ft LED/COB
35W sq ft CMH/LEC
60w/ sq ft cfl

Bolof · Nov 5, 2016

majins said:
Watt isnt a very good measurement since different light sources will give different amount of light for the same power.

But 50W per sq ft seems to be what people aim for when I was researching the same question.

Tnx for the reply. Yes, I am aware of different light sources. I was mainly thinking abour flower Room with HPS since flower Room is where most light is needed and HPS most efficient light source.

Bolof · Nov 5, 2016

Porky101 said:
50w/ sq ft HPS
40W sq ft MH
30W/ sq ft LED/COB
35W sq ft CMH/LEC
60w/ sq ft cfl

Why less watt for MH that is much less efficient then HPS?

Porky101 · Nov 5, 2016

Efficient depents who you are asking.

Hps makes more lumens watt per watt but MH makes more usables lumens for the plant compared to usable lumens of HPS.

So 80W MH = 100W HPS not in terms of power pull, in terms of actual light...

Google "Best visible spectrum for plants"

majins · Nov 5, 2016

HPS is one of the lower efficient light sources unless your talking $ to Watt and not Watt to Par.
LED and LEC are the most efficient for watt to par,

Bolof · Nov 5, 2016

Porky101 said:
Efficient depents who you are asking.

Hps makes lore lumens watt per watt but MH makes more usables lumens for the plant compared to usable lumens of HPS.

So 80W MH = 100W HPS not in terms of power pull, in terms of actual light...

Google "Best visible spectrum for plants"

Interesting. But are you talking veg. Or flower? I have read a lot and most say that HPS much better for flower. MH spectrum only good for veg.

ttystikk · Nov 5, 2016

Porky101 said:
50w/ sq ft HPS
40W sq ft MH
30W/ sq ft LED/COB
35W sq ft CMH/LEC
60w/ sq ft cfl

Not a bad starting point, good chart- as ever, with a few qualifications.

majins said:
HPS is one of the lower efficient light sources unless your talking $ to Watt and not Watt to Par.
LED and LEC are the most efficient for watt to par,

EXCELLENT POINT, and well said; the current advantage of light bulbs of any of the common forms is low cost of acquisition. After that, it all goes the other way.

ttystikk · Nov 5, 2016

Bolof said:
Interesting. But are you talking veg. Or flower? I have read a lot and most say that HPS much better for flower. MH spectrum only good for veg.

This is badly outdated information.

Today, nothing beats COB LED and other advanced LED types for performance, spectrum, efficiency or longevity.

The key is to understand that if you want a highly efficient LED rig, you will be paying for it, up front, in terms of additional cost to purchase. After that, you're saving money, forever.

Porky101 · Nov 5, 2016

ttystikk said:
This is badly outdated information.

Today, nothing beats COB LED and other advanced LED types for performance, spectrum, efficiency or longevity.

The key is to understand that if you want a highly efficient LED rig, you will be paying for it, up front, in terms of additional cost to purchase. After that, you're saving money, forever.

Becarefull though, some LEDS are worse than HPS.

ttystikk · Nov 5, 2016

HPS in single ended form is badly outdated. Metal Halide is WORSE. 315W CMH is a very good choice, perhaps the best HID has to offer. 3100K for bloom, 4000K for veg.

My best advice is not to buy light bulbs. They just aren't the best option anymore.

Porky101 said:
Becarefull though, some LEDS are worse than HPS.

Swallow hard and buy a decent COB LED fixture from a reputable seller, such as Johnson Grow Lights here on RIU. You'll get all the benefits and performance from the first day you use it onward.

Bolof · Nov 5, 2016

majins said:
HPS is one of the lower efficient light sources unless your talking $ to Watt and not Watt to Par.
LED and LEC are the most efficient for watt to par,

PAR is what counts of course. According to this reference to science. HPS gives much more par then MH. https://www.thcfarmer.com/community/threads/metal-halide-vs-high-pressure-sodium-an-age-old-question-for-cannabis-growers.71496/

ttystikk · Nov 5, 2016

Now, back to the original question! The better the light source, the less watts per square foot are required.

HPS 65W/sq ft
MH 75W/sq ft
CMH 40W/sq ft
LED driven hard 40W/sq ft
LED driven softly 30W/sq ft
Extreme efficiency LED setups 20W/sq ft

Bolof · Nov 5, 2016

ttystikk said:
This is badly outdated information.

Today, nothing beats COB LED and other advanced LED types for performance, spectrum, efficiency or longevity.

The key is to understand that if you want a highly efficient LED rig, you will be paying for it, up front, in terms of additional cost to purchase. After that, you're saving money, forever.

Yes. Problem is much info on internet on this topic is outdated and not reliable. Most just repeat what others say or have subjective bias. I read lots of people say that LED is not good enough yet.

ttystikk · Nov 5, 2016

Bolof said:
PAR is what counts of course. According to this reference to science. HPS gives much more par then MH. https://www.thcfarmer.com/community/threads/metal-halide-vs-high-pressure-sodium-an-age-old-question-for-cannabis-growers.71496/

860W CDM Allstart lamps give much more PAR than either of those, but there are good reasons they aren't in wider use. One is that they need to run in a vertical position, limiting reflector options, and the other is simple inefficiency. They need to run on low frequency drivers and magnetic ballasts are the most available of the options, but they suck power and don't put out the intensity.

Again, the best options are now all various types of LED and these will continue to get more affordable and widely available as time goes on.

ttystikk · Nov 5, 2016

Bolof said:
Yes. Problem is much info on internet on this topic is outdated and not reliable. Most just repeat what others say or have subjective bias. I read lots of people say that LED is not good enough yet.

I've done the analysis and came to the opposite conclusion a year ago, when chips were much more expensive than they are now.

And this is up to the minute info, nothing 'outdated' about it.

Bolof · Nov 5, 2016

ttystikk said:
Now, back to the original question! The better the light source, the less watts per square foot are required.

HPS 65W/sq ft
MH 75W/sq ft
CMH 40W/sq ft
LED driven hard 40W/sq ft
LED driven softly 30W/sq ft
Extreme efficiency LED setups 20W/sq ft

That number for MH sounds right. It is less efficient then HPS as you say.

ttystikk · Nov 5, 2016

Bolof said:
That number for MH sounds right. It is less efficient then HPS as you say.

If you feel you need to go with light bulbs, your best bet is 315W CMH lights.

Bolof · Nov 5, 2016

ttystikk said:
I've done the analysis and came to the opposite conclusion a year ago, when chips were much more expensive than they are now.

And this is up to the minute info, nothing 'outdated' about it.

Yes. That was kind of my point. I dont find the argument against LED reliable. Many prefer HPS because cheaper and they used to it.

optimal watt / square foot or m2

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