Susan Erickson wrote in message . ..
On Mon, 06 Sep 2004 17:24:43 GMT, "GARLAND HANSON"
wrote:


I'll be using 48" tubes. The fixtures and tubes seem to be plentiful at
Home Depot and Lowes. I'd like to have lighting that is effective, quiet,
and economical. Can I have all three???


Most of us that have used the HD fixtures pick CHEAP. CHEAP
fixtures and Cheap bulbs. So it is generally 2 2-bulb fixtures
per shelf. The effect of 4 lamps. Within a hand span of the
leaves. Ray has an article about light on plants and the drop
off of effectiveness caused by distance. www.FirstRays.com in
his free stuff.

The general rule is that light intensity from a diffuse source is
inversely proportional to the distance from the source.

From a point source the intensity is inversely proportional to the
square of the distance, but a fluorescent light is best considered as
a collection of point sources.

(See, Ray, I remembered from our first encounter umpteen years ago, I
think)

Output will decrease with the age of the tubes, too.

J. Del Col