[APD] Re: Lighting

["Daniel Larsson" <defdac at hotmail_com>]

S. Hieber said:

>Things that probably will matter as much or more for
>lighting are the particular ballast used with a partiuclar
>lamp, the lamp (reflector) and bulb combination, hours of
>illumination, and whether the *manufacturer's* rating for
>output is based on post-burn-in and if so, how many hours
>after burn-in. Over and above this, nutrient levels,
>including CO2, and maintenance habits of the gardener may
>have effects that swamp the diffs between this bulb or
>that.

Absolutely, I don't calculate these numbers to help you
grow plants. You can do it with a Halogen if you 
would like to.

But it's not very cost effective, and it's interesting to
see that for example Halogens are about 4-5 times
less efficient than the best tubes growing plants.

You can grow plants with Sodium lamps with just
one output-spike in the yellow part of the spectrum,
but it's ugly and inefficient.

You can use fancy pantsy bulbs with extremely nice
color rendering making everything look good, but
it still would be inefficient because the bulb must
filter the light very much to get really good color
rendering, and thereby making it output less intensity.
Notice those fancy T5:s having rather poor PUR-
efficiency: It's because they're filtered to get really
nice colors.

It's just nice to be able to get a bulb that conforms to the
photosynthesis action spectrum rather good and
also have nice color rendering and also are efficient
growing plants, that's at least what I use the numbers
for. 


// Daniel.
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