Cereus-validus. wrote:
"This winter I bought a 400W HID high pressure sodium lamp which allows for
a 16 square foot simulated "summer" garden inside. After the cuttings root
I'm hoping to simulate Spring in late Fall."

That's insane. Are you hoping to burn your house down from the intense heat
that will generate?

In any case, the sodium bulbs produce most of their light in the yellow
range of the spectrum which is no benefit at all to plants. At the very
least, you are wasting your money.


It has been my experience that plants do like HPS lighting, although
perhaps not as much as they like fluorescent lighting if you can get the
intensity they need.

The lamp produces only a little more heat (and less intense heat) than a
300W halogen lamp, which are commonly used in floor lamps.

All that heat doesn't get wasted if you run the lamps in the winter --
it helps to heat you house. It will be noticable on your electric bill.
If you run the lamps during the summer, it can really get expensive
because you have to pay (air conditioning) to remove all that heat.

I used to run a 400W HPS and a 400W MH lamp at the same time in a small
basement room in the winter, but I decided it cost too much so now I
just run the HPS and a few F32T8 fluorescents.

Bob