On Sep 13, 10:42 pm, SuE wrote:

Save the money to take him out for a steak dinner and buy standard
fluorescent tubes. Run 4 tubes per shelf and adjust the height of
plants so similar heights and light needs are on a shelf. Then adjust
the light fixture to that height. Low light plants can sit beneath
some tall ones - but remember light decreases Radically fast as you
increase the distance. ...

From a point source, light obeys the inverse square law of radiation,
i.e. the intensity of the light decreases as the inverse of the square
of the distance. For example a light twice as far away will be 1/4 as
intense, three times as far, 1/9 as intense, etc.

HOWEVER, from a large or diffuse source such as a fluorescent tube,
the falloff is less drastic because the tube is, in effect, a large
number of overlapping point sources. The handy rule for such a source
is that the intensity falls off as the inverse of the distance, i.e.
twice as far ,1/2 as intense, three times as far, 1/3, etc.

J. Del Col