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

I don't know about how good they are, but I'd say that fluorescents were
more energy efficient that the sodium lamps.

OTOH, I wonder how my metal halide lights from my old fish tank would do
with plants.

"Jeffrey Barker" wrote in message
om...
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

Jeffrey Barker said:

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.

They produce more lumens of light per watt. But as to best, that depends
on what you plan to do with them.

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

The ones with the weird orange color.

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.

Metal halide lamps will produce better tseedlings for transplant than
high pressure sodium. Their spectrum is much closer to that of sunlight.
The light output of a sodium lamp is all in the long (orange/red) wavelengths
and will lead to a leggier plants. Sodium lamps are often used as
supplemental light in greenhouses, because the long wavelength light
encourages blooms. The greenhouse plants get enough natural sunlight
with short (blue) wavelegths to keep them from getting leggy.

In my opinion if you want to put large amounts of light into a compact space,
metal halide lamps are the way to go. I use a 250 watt metal halide lamp for
starting all of my tomatoes, peppers, and eggplants. But I also have a couple of
flourescent fixtures which I use as supplementary light for starting bedding
flowers in an east-facing window.
--
Pat in Plymouth MI

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)

Pat Kiewicz wrote

They produce more lumens of light per watt

exactly, in general the higher wattage you go the more light you get for your
money.

Metal halide lamps will produce better tseedlings for transplant than high
pressure sodium.

I disagree 100%. I understand the blue/orange light reasoning but I've used
Sodium 6 yrs straight with no
problems whatsoever. Have a look at last years seedlings.

http://members.aol.com/sallythediyer/page1.html/

(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).

"simy1" wrote in message
om...
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).

I'm sorry to butt in suddenly, but this is totally wrong. The reason why
chlorophyll is green is that it reflects green light and does not absorb it.

"FDR" wrote in message
...
I don't know about how good they are, but I'd say that fluorescents were
more energy efficient that the sodium lamps.

No, HPS (high pressure sodium) lights produce a lot more light per watt of
electricity used than fluorescent lights. HPS is more efficient than metal
halide too. On the topic of which to choose; if it's just for seedlings
then it won't make much difference, because seedlings don't really need much
light (even fluorescents will do fine). But if you want it for growing
fruit etc indoors during winter, then go for the Sodium light. It's more
efficient than either fluoro or MH, and it gives out the best sprectrum for
blooming. It'll probably cost you more than $20 though, as you'll need a
ballast and fixture as well as the bulb (*DON'T* just put a HPS bulb in an
ordinary light fitting, unless you like bright flashes and white hot glass!
:-p )


OTOH, I wonder how my metal halide lights from my old fish tank would do
with plants.

Yesm metal halide lights will work well, particularly for vegetative growth,
HPS is best for blooming though.
JohnnyJ