light meter

Let me start by saying I not totally clear about the difference between lumens, lux, and footcandles; but I have some knowledge.

I am thinking about the Hydrofarm digital light meter. Is this a good meter? It is only $50, while some cost much more. They also have an analog meter for $30. What meter do you guys recommend?

A hortilux 1000w is supposed to have 145,000 inital lumens. Is this more than 5000 footcandles? How can I compare a brand new 1000w to the amount of light in a greenhouse? Will the meter be able to measure the amount of light in a greenhouse? I would like to take measurements throughout the day in a greenhouse and see how they compare to the rated output of a hortilux 1000w (145,000 lumens initially.) Will the Hydrofarm digital light meter be able to do this?

bump, please reply

Why bother with a light meter? Its not that useful of a tool. Unless you are doing a larger grow and trying to maximize a light mover. Or trying to figure out for yourself that CFLs aren't all that great.

Put that $ towards a good light.

agree... you can always tell how much light your plants are getting by taking the lumens your light puts out and dividing it by the square footage of your grow area.

For example: A 600w HPS bulb puts out 90,000 lumens. If your grow area is 3x3 you have 9 square feet. So your plants would be recieving 10,000 lumens per square foot... which happens to be about the strength of sunlight.

yanksck73 said:

agree... you can always tell how much light your plants are getting by taking the lumens your light puts out and dividing it by the square footage of your grow area.

For example: A 600w HPS bulb puts out 90,000 lumens. If your grow area is 3x3 you have 9 square feet. So your plants would be recieving 10,000 lumens per square foot... which happens to be about the strength of sunlight.

Click to expand...

would plants do better if lumens were twice the strenght of sunlight?