How do you measure Florescent light output
 

Does anyone know a rule of thumb for measuring light output? Basically, what wattage do I use for cattleya culture, and what should I use for phalaenopsis or paphiopedilum? I know that distance from the bulbs also matter, so how far should they be from the source. I find reference to measuring such light in foot-candles, but how do you find the footcandle output of florescent bulbs? I have a light meter, but it will not register florescent light. Is this common or do I just have a cheap meter (it IS a cheap meter for that matter)? Info or link to a good instruction page would be appreciated!
Steve

its best to measure light in foot candles, not in watts. because 48 watts of t12 is alot less than 48 wats of T5HO. Cattleyas in general like 2,500-3,5000 foot candles and phalaenopsis generally like 1,000-2,000 foot candles. light levels can exceed those above, but not without added air flow, moisture, humidity, etc.


what light meter do you have? some light meters do not measure footcandles and you have to put the level you get and plug it into some equation to change units from say lux (or whatever its metering) into foot candles... there are free light meter apps you can get if you have an iphone or ipod touch with a camera though.

i have been growing under lights for years and i have never used a light meter until i recently got the iphone app. the best light meter there is are your plants, watch the color of the leaves, too dark means too little light. likewise, leaves that are too bright mean that the lighting is too high.

Call-me-bob:
Thanks for the input. I have always used the test-by-color system, was just wondering if there was a better system to calculate quickly rather than the more or less trial and error.
Thanks again for the input!
Steve

sure thing! :) after a while you develop an "instinct" and can decide where to place things without the use of a meter