lighting questions
Brian Dugas
hardware stores and Wal-Marts? Are these full spectrum bulbs? Can the
spectrum be controlled with CF's? Isn't spectrum more important than
wattage?
2) What spectrum do plants need the most? I made the mistake of asking some
moron about what lights I should get for my plant tank, and he wanted to
sell me 2 marine lights. He was saying the blue light is more important
than red, and that plants don't even need red. Was he correct? Which do
plants prefer?
Thanks in advance.
Brian
Wayne Jones
"Brian Dugas" <du...@home.com> wrote in message
news:8sFR6.30551$qs3.13...@news2.rdc2.tx.home.com...
> 1) What is the general opinion on the screw-in compact flourescents
found at
> hardware stores and Wal-Marts? Are these full spectrum bulbs? Can
the
> spectrum be controlled with CF's? Isn't spectrum more important than
> wattage?
>
Screw-in CFs are somewhat less efficient than 3' or 4' regular
fluorescents, cost more, don't last as long and don't come in a wide
selection of spectrums. They are best for places where longer lamps
won't fit. I don't think I have seen a full spectrum lamp in these types
of lamps. I wouldn't use them unless PCs wouldn't fit.
Spectrum is not more important than wattage unless you have a wildly
inappropriate light source like a green laser or something. Any lamp
that would not grow plants is also likely to look bad so no one would
want them anyway.
> 2) What spectrum do plants need the most?
No one really knows for sure. It will vary with individual plant species
but you want a lamp that produces light in the 400 to 700 nanometer
range and has a significant amount of blue light and red light and
visually looks good to you. I prefer high CRI lamps with spectrums
similar to sunlight. This satisfies both criteria. Most people like
5000K to 6500K lamps. I don't mind 4100K at all as long as they have a
high CRI.
>I made the mistake of asking some
> moron about what lights I should get for my plant tank, and he wanted
to
> sell me 2 marine lights. He was saying the blue light is more
important
> than red, and that plants don't even need red. Was he correct?
Most plants require both red and blue light to grow properly. In fact,
they show a considerably greater response to red light. Most people seem
to have the mistaken idea that plants are very selective and only use
light from a very narrow wavelength bands. While this is true that the
photosynthetic response of plants peaks at certain wavelengths the peaks
are not that strong and virtually all wavelengths between 400 and 700
nanometers are likely to be usable. Take a look at this action spectrum
which was derived by averaging the photosynthetic response of many
different plant species.
http://ss.jircas.affrc.go.jp/engpage/jarq/33-3/tazawa/fig5.htm The curve
is much flatter than you might imagine. Note also that you don't have to
go searching for a lamp with a spectrum that exactly matches this curve.
We are growing aquatic plants and there is no data available and we want
lamps that look good too. As well it has been clearly shown that lamps
with very different spectrums than this will grow aquatic plants. The
only thing you can't do is pick a light source that is outside the
400-700 range or pick one that is missing either red light or blue
light. Unfortunately, that is exactly what your sales person was trying
to do.
Wayne
Andy G
in the corners and they work great. I got mine for $5.25 minus a $5 rebate
(almost free). Spectrum is generally regarded as important, but I saw a
scientific paper (at the Krib I think) that showed varying the spectrum of a
certain wattage of light only made a 5%-10% difference in the growth etc. of
plants. The papers conclusion was don't worry about spectrum too much. My
practical experience with the cheap CFs seems to indicate the paper is
correct.
Visit my Aquarium Resource page at
http://members.tripod.com/~andygags/AquariumR.htm
with new tank pictures
Ron Santos
>
> 2) What spectrum do plants need the most? I made the mistake of asking some
> moron about what lights I should get for my plant tank, and he wanted to
> sell me 2 marine lights. He was saying the blue light is more important
> than red, and that plants don't even need red. Was he correct? Which do
> plants prefer?
Below is a discussion from the veterans/experts on the topic. As usual, there
seems to be varying opinions on the matter, so you'll have to draw your own
conclusions.
Ron Santos
Brian Dugas wrote:
> 2) What spectrum do plants need the most? I made the mistake of asking some
> moron about what lights I should get for my plant tank, and he wanted to
> sell me 2 marine lights. He was saying the blue light is more important
> than red, and that plants don't even need red. Was he correct? Which do
> plants prefer?
Here's another discussion on the topic while I was looking for solutions to may
algae problem.
http://www.actwin.com/fish/aquatic-plants/month.200011/msg00520.html
lmiski
flourescents found at hardware stores and Wal-Marts? Are
these full spectrum bulbs? Can the spectrum be controlled
with CF's? Isn't spectrum more important than
wattage?<<
Some people have used them with sucess.
I just recently purchased a Lights of America floodlight fixture
from home depot. 65 watts, 6500k, reflector included, for 30
$. Working fine so far. Many reef people have used them on
their refugiums. It might be a good low-cost option for you.
Replacement bulbs are only 12$. check out my website under
links for more info, and for a link to the relevant reef
discussions where they discuss this fixture.
>>2) What spectrum do plants need the most? I made the
mistake of asking some moron about what lights I should get
for my plant tank, and he wanted to sell me 2 marine lights.
He was saying the blue light is more important
than red, and that plants don't even need red. Was he
correct? Which do plants prefer?<<
I don't think that what this person said is true. One of my
source books says that plants absorb across a fairly broad
spectrum with peaks at 380-480nm (violet-blue) and 600-
680nm (orange-red). Having said that, I think current thought
is that wattage, no matter the Kelvin or spectrum is more
important than buying fancy, expensive bulbs that supposedly
produce light more in line with what plants like. Your two
most important considerations should be, do I have enough
light output, and do I like the color of the light. Anything
under 5000k is probably two yellow for most people's tastes.
I have seen great tanks that use only 10,000K bulbs (usually
used for marine). In fact all the tanks in the "outside gallery"
of my website use 10,000k VHO.
a.
http://www.geocities.com/anwestover
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Ivo Busko
<snip>
> won't fit. I don't think I have seen a full spectrum lamp in these types
> of lamps. I wouldn't use them unless PCs wouldn't fit.
There is this one:
http://www.jade-mtn.com/lightingProducts/ott-lite.html
-Ivo