If you're a CFL micro grower like me, I'm sure you've been seeing more and more LED bulbs appearing in your local box stores next to the CFLs.
Maybe you're wondering, like I was, are these things any good for growing?
I know my initial impressions from what I was seeing on the shelves, was no.
The bulbs put out half the lumens that the same wattage CFL put out or the lumens were close but the only bulb was PAR style bulbs with big metal heatsinks and thick glass reflectors, not to mention expensive.
Then one day I was at Lowes and I saw some 2700k LED bulbs that said they put out roughly the same lumens as similar wattage CFLs and they weren't outrageously priced (2 bulbs for $14). This got me intrigued, so I bought some.
I have always wanted to make a thread showing just how much light actually comes off a CFL bulb at varying distances, but I never got around to it. I figured testing some similar wattage, same color LED and CFL bulbs might be interesting. Both to show how much light comes off the CFL bulbs and to see how these LED bulbs compare.
I used this light meter.
Here's a front view so you can see it has a pretty low profile.
The part that measures the light is about 3/4" taller than what the meter is sitting on.
CFL bulb lumen measurements are done at 12" by the manufacturer.
Lumens are actually kind of complex because they measure the light over an area instead of a reading at a point a certain distance from the light.
I'm measuring lux. This is going to be a simple reading showing the amount of light from the source in a direct line.
I will be putting the meter directly under the light and measuring at 12". I will then measure 12" to the side at 12" height.
The next measurement will be at 6" height and the last measurement at 9" height.
This means the light source will roughly be about 11" from the meter, 5" from the meter and 2" from the meter.
Really the heights don't matter as long as all the measurements for all the lights are taken at the same heights.