GardenBanter.co.uk - View Single Post - high-density sodium lamps as grow lights?

14-04-2003, 05:56 PM

(Jeffrey Barker) wrote in message . com...
I recently read in a gardening book that high-density sodium lamps
were much better than any other type of lamp to use as grow-lights.

It seems that high-density sodium lamps are the same type used for
streetlights and home security.

Does anyone know if this is the case? If so, I'd rather drop $20 or
so on a huge lamp that would (I imagine) be useful for all of my
seedlings and plants, since it's so bright, instead of several
flourescent lamps, which need to be kept very close to the plants.

Thanks in advance for any help.

Jeffrey

It may be true but I doubt it. Sodium lamps radiate only at 589 nm.
Many experiments with a variety of plants showed best absorption in
the green and green-blue (350-420nm), which makes a lot of sense since
chlorophyll is, after all, deep green, so you need anything green or
shorter wavelength (higher energy).