Lux & lumens

[HotshotShorty]

Greetings,

Lighting is an important and confusing subject.

While I do not claim to be an expert, but I would like to relay my understanding of the subject.

First, you can get a light with a certain light output. THAT, would be lumens. THAT would be total light output without regard to direction of the light.

Second, you have LUX and that would be the intensity of light. Lux is what you would be interested in. In other words, what is the intensity of the light on your plants.

Who cares about the lumens, because your plants do not "see" the total light output of your lamp.

So I got a light meter. It measures the intensity of the light at a single point. The measurement is in LUX.
I found out that my cheap reflector creates hotspots 50% of greater intensity. I moved the shortest plants to the brightest points and It told me which plants were getting too much and which were not getting enough.

 

[Fuzzy Duck]

Interesting link... high lighted some areas of knowledge which i have over looked plus reps

 

[cannasensei]

Great link. Lux is important, I focus more on par personally

 

[HotshotShorty]

Illuminance Surfaces illuminated by:
10−4 lux Moonless, overcast night sky (starlight)[2]
0.002 lux Moonless clear night sky with airglow[2]
0.27—1.0 lux Full moon on a clear night[2][3][4]
3.4 lux Dark limit of civil twilight under a clear sky[5]
50 lux Family living room lights (Australia, 1998)[6]
80 lux Office building hallway/toilet lighting[7][8]
100 lux Very dark overcast day[2]
320—500 lux Office lighting[9][10][11]
400 lux Sunrise or sunset on a clear day.
1,000 lux Overcast day;[2] typical TV studio lighting
10,000—25,000 lux Full daylight (not direct sun)[2]
32,000—130,000 lux Direct sunlight

Lux - Wikipedia, the free encyclopedia

Daylight intensity in different conditions
Illuminance Example
120,000 lux Brightest sunlight
110,000 lux Bright sunlight
20,000 lux Shade illuminated by entire clear blue sky, midday
10,000 - 25,000 lux Typical overcast day, midday
<200 lux Extreme of darkest storm clouds, midday
400 lux Sunrise or sunset on a clear day (ambient illumination).
40 lux Fully overcast, sunset/sunrise
<1 lux Extreme of darkest storm clouds, sunset/rise

Daylight - Wikipedia, the free encyclopedia

MAXIMUM LIGHT REQUIREMENTS FOR PLANTS---JORGE CERVANTES
SEEDLINGS---4,000 LUX
CLONE--------4,000 LUX
VEGETATIVE--27,000 LUX
FLOWERING---107,000 LUX​