How many lumens does the Sun produce per square foot?

ArrOgNt RocKstAR

ArrOgNt RocKstAR

Well-Known Member
I'd like to know how many lumens the sun produces per square foot... like compared to a 1000 watt bulb.

Anyone have an idea?:roll:
 
rabbogart

rabbogart

Well-Known Member
The general "rule of thumb" I use is between 1 and 1,000,000,000 per square foot but I cannot give an exact number.
 
B

Bulldog73

Active Member
well to technically answer your question it would depend on how far away from the sun you were and apply the inverse square law to your distance... Lumens have nothing to do with how plants use or see PAR light. Lumens is useful when comparing like for like lighting to know which one will have more intensity but higher lumens doesn't mean better. The spectrum of light is much more important... 100,000 Lumens in the green spectrum won't do shit for your plant...
 
kvnbeach

kvnbeach

Active Member
budman111 said:
Fate, it seems is not without a sense of irony.
Click to expand...
You are wondering around with a quote of mine. I am honored. I have a lumen reader, 10,000 is about right. So it is equivelant to a 250w halide. Difference is, it is 10,000 lumens anywhere on the plant. In otherwords, the light can actually penetrate through the canopy and reach lower leaves. A 250 cant do this from 93,000,000 miles. The sun does not lose intensity, but anything over a 400 produces more lumens to the canopy than the sun. You need a 1000w to be able to penetrate through the canopy. It's good to have he light hit the dirt with some intensity.

I said PENETRATE. ha ha ha hahahaha ha ha hahahahaha
 
O

only71

Active Member
Light Requirements of "High Energy" Plants
1000 - 5000 luxMin. necessary for life
10000 - 15000 luxMin. necessary for consistent but sparse growth
20000 - 25000 luxMin. necessary for robust growth
25000 - 30000 luxMax. Efficiency for Sub Tropical varieties
25000 - 50000 luxMax. Efficiency for Equatorial varieties
Plants need 25000-50000 lux too grow fast.
90000 lux Max. Sunlight Intensity on Earth's surface This is too much light, it is not good for the plant.
Plants subject to intensities at this level or greater are at risk of "solarization," whereby photosynthesis is retarded. This can happen at noon on a clear Tropical summer day, especially at high altitudes.
140000 lux Sunlight above atmosphere (Solar Constant)
 
W

wutux

New Member
lulutheblack said:
google it!
Click to expand...
Hi I am new :) I googled and all I get is rollitup forums :D

But I have this book Kaiser's electrotechnical handbook from Dragutin Kaiser 1971 edition it has some pages about all kinds of different lamps in that time and there is also one table about characteristics of different light sources and among all light sources there is also:

Sun 30° above horizon colour temp. 5200 K | efficiency of light source lm/W= ---(no data) | luminance approximately = around 75 000 sb or cd/cm^2

Sun in zenith(heyday) or sun at it's peak colour temp. 5200 K | efficiency of light source lm/W=---( no data) | luminance approximately = around 225 000 sb or cd/cm^2

1 sb or 1 Stiebel is 1 cd/cm^2

I tried to find how much lumens is that and all I can find that 225 000 cd/cm^2 is 2 250 000 000 lux which is 2 250 000 000 lm/m^2 or 2 250 000 000 lumen/square meter/steradian

1 lm/m^2 = 0.09290304 lm/foot^2

So 2 250 000 000 lm/m^2 is 209031840 lm/foot^2

It does not says anywhere on which latitude is this. I checked this calculations several times and I am pretty sure I made no mistakes, yes I am drunk a bit, but I still ask my self now how the fuck any plant can grow under any type of lamps. I am going to have to recheck this tomorrow again :D
 
vostok

vostok

Well-Known Member
A silly question that will only result is a silly answer...
really this depends on so many factors,
like where on the earth you are and what 'season'
better for you to totally understand what EXACTLY is a lumen...vs..foot candle ...vs.. a lux ..? lol
 
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