"Martin" wrote in message
...

[snip]

perhaps this http://www.hydroponics.com/light/growlamps.htm

I had a look

I think they are trying to pull the wool over my eyes, unless there is
something fundamental which I misunderstand. I thought the light was
only used by the plant for photosynthesis of carbohydrates from CO2
and water. So why do they waffle about spectra which are adjusted for
good fruiting versus good vegetative growth?

I have little faith in an organisation which thinks the plural of
"wattage" is "wattage's"

Some of their internal links don't work.

[snip]

Franz