Stella Hackell wrote:

"Mahasamatman" wrote in message arthlink.net...

You will have far better results with metal halide bulbs, or at least HO
type flourescents. The regular tubes don't produce quite enough light,
though some people make them work for them. There is a nice self-ballasted
75W reflector metal halide bulb on the market now that is inexpensive and
easy to use.


Excuse me if this is a dumb question, but does one need a special fixture
to use metal halide bulbs? Or do they screw into a regular light socket?
I'm very impatient to get some seeds started indoors, but I'm also
trying not to break the budget.

Thanks for any advice!

Stella


A self-ballasted light will screw into a standard incandescent socket --
but I've never seen a self-ballasted MH lamp. I have hight-pressure sodium
lights, metal halide lights, and triphosphor fluorescents. The
fluorescents are far cheaper and the plants do better with them. Look for
a shop light or "troffer" style fixture for suspended ceilings that uses
F32T8 lamps, with normal brightness or high brightness. The lamps you want
are 4' long and look like normal fluorscents except they are one inch in
diameter instead of 1.5". Look for something with a designation of "835"
or "830" or "SPX30" (this indicates the color, or "warmness", and the color
rendering, or "naturalness"). The lamps are usually less than $2 each at
Home Depot or at a commercial lighting store. Forget the "one warm white
and one cool white" conventional wisdom -- that worked 20 years ago before
EPACT ruined 40W fluorescent lamps. These new triphosphor lamps are better
anyway. Some of them (like Philip's or Sylvania's "Alto" series with the
green endcaps) are low mercury.

F32T8 lamps have an expected life of about 20000 hours, and an expected
useful life of about 20000 hours. The old lamps had an expected life of
22000+ hours but you had to replace them at about 10000 hours or less
because they lost too much brightness.

If you already have 4' fluorescent grow lights, you can upgrade the
ballasts to use the new lamps for less than $20 per fixture. Try to find
an electronic ballast with a "ballast factor" (not to be confused with
"power factor") of greater than 1.

Best regards,
Bob