How much of the length of a 24" / 20 watt tube emits enough light to
produce strong initial plant growth?

The best most even light is in the center 20 inches. Remember that
fluorescent lamps are not always the best single source of light. It
depends on the plant etc. Most of the time you would be better served by
using a mix of fluorescent and incandescent light.

--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math


"Dr. Rev. Chuck, M.D. P.A." wrote in message
...
How much of the length of a 24" / 20 watt tube emits enough light to
produce strong initial plant growth?

Joseph Meehan wrote:

The best most even light is in the center 20 inches. Remember that
fluorescent lamps are not always the best single source of light. It
depends on the plant etc. Most of the time you would be better served by
using a mix of fluorescent and incandescent light.

My 48" fixtures have never failed to produce robust transplants, rivalling
anything I've seen at the local garden store. Prob is, 48" racks have a
large footprint. Easier to fit a 24" stand in the kitchen.

It does depend on the type of plant and the type of lamp, but most
plants like a specific mix of light colors. Fluorescent lamps do not have a
nice complete mix of colors, if you look at their spectrum you will see they
are bright line with lots of large holes. A little incandescent light which
has a smooth spectrum can help with many plants and allow a lower total
light with better results.

If it works for you then don't worry.

--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math


"Dr. Rev. Chuck, M.D. P.A." wrote in message
...
Joseph Meehan wrote:

The best most even light is in the center 20 inches. Remember that
fluorescent lamps are not always the best single source of light. It
depends on the plant etc. Most of the time you would be better served
by
using a mix of fluorescent and incandescent light.

My 48" fixtures have never failed to produce robust transplants, rivalling
anything I've seen at the local garden store. Prob is, 48" racks have a
large footprint. Easier to fit a 24" stand in the kitchen.

On Fri, 04 Jul 2003 10:29:50 +0000, Joseph Meehan wrote:

It does depend on the type of plant and the type of lamp, but most
plants like a specific mix of light colors. Fluorescent lamps do not
have a nice complete mix of colors, if you look at their spectrum you
will see they are bright line with lots of large holes. A little
incandescent light which has a smooth spectrum can help with many plants
and allow a lower total light with better results.

If it works for you then don't worry.

If you was to mix a cool white with a warm white you would end up with a
near complete spectrum. I've had great luck with a shop light (blue'ish
light) mixed with a kitchen/bath (red'ish light) You could also purchase
full spectrum bulbs (growlux) or fish tank bulbs. These have a phosphorus
coating inside the bulb which help to create a fuller spectrum. All in
all, a fluorescent lighting system can be rather cheap or it could get
expensive, it really depends on what you want to spend on it. After you
buy a light fixture (10 to 50 dollars) and two bulbs (5 to 45 dollars),
you could be in for a 100 dollar bill. If your looking for a better
lighting system I would suggest a hps (high pressure sodium) or a mh
(metal halide). The hps bulb puts out red light and mh bulbs put out blue.
There are bulbs that put out both. The ones I've used are called ag-grow
which are equal red and blue. They are great. A 150 watt hps system can
sell for as low as a 100 dollars and they give far more lummens than
fluorescents ever could produce watt for watt.

Well maybe not near complete spectrum, but better and may well be
good enough. It depends on the plants and the stage of their development.

--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math


"Timothy" wrote in message
If you was to mix a cool white with a warm white you would end up with a
near complete spectrum. I've had great luck with a shop light (blue'ish
light) mixed with a kitchen/bath (red'ish light) You could also purchase
full spectrum bulbs (growlux) or fish tank bulbs. These have a phosphorus
coating inside the bulb which help to create a fuller spectrum. All in
all, a fluorescent lighting system can be rather cheap or it could get
expensive, it really depends on what you want to spend on it. After you
buy a light fixture (10 to 50 dollars) and two bulbs (5 to 45 dollars),
you could be in for a 100 dollar bill. If your looking for a better
lighting system I would suggest a hps (high pressure sodium) or a mh
(metal halide). The hps bulb puts out red light and mh bulbs put out blue.
There are bulbs that put out both. The ones I've used are called ag-grow
which are equal red and blue. They are great. A 150 watt hps system can
sell for as low as a 100 dollars and they give far more lummens than
fluorescents ever could produce watt for watt.

On Fri, 04 Jul 2003 17:19:18 +0000, Joseph Meehan wrote:

Well maybe not near complete spectrum, but better and may well
be
good enough. It depends on the plants and the stage of their
development.

Red light is generaly assoiciated with flowering and blue light is
generally assoiciated vegetative growth. This can be seen in nature with
spring light (more blue) and summer light (more red). Your not really ever
going to get true 'full spectrum' from any light source, be it
fluorescent, hps or mh. Some get rather close (grow-lux and ag-grows), but
no affordable light source will replicate the suns spectrum. The only
light which is almost near sun spectrum is the sulphur type bulbs and the
led lights. The sulphur bulbs are not ready for market (if they ever will
be) and are increadibly expensive to make. The led lights are very new and
expensive for the general consumer. They could turn out to be only as good
as the fluorescents as far as total lummen out put and intensity, but I
can't afford one to find out.

Some reading material on sulphur lights...
http://www.thekrib.com/Lights/sulphur.html

Timothy wrote:

On Fri, 04 Jul 2003 17:19:18 +0000, Joseph Meehan wrote:


Well maybe not near complete spectrum, but better and may well
be
good enough. It depends on the plants and the stage of their
development.


Red light is generaly assoiciated with flowering and blue light is
generally assoiciated vegetative growth. This can be seen in nature with
spring light (more blue) and summer light (more red). Your not really ever
going to get true 'full spectrum' from any light source, be it
fluorescent, hps or mh. Some get rather close (grow-lux and ag-grows), but
no affordable light source will replicate the suns spectrum. The only
light which is almost near sun spectrum is the sulphur type bulbs and the
led lights. The sulphur bulbs are not ready for market (if they ever will
be) and are increadibly expensive to make. The led lights are very new and
expensive for the general consumer. They could turn out to be only as good
as the fluorescents as far as total lummen out put and intensity, but I
can't afford one to find out.

Some reading material on sulphur lights...
http://www.thekrib.com/Lights/sulphur.html


Triphosphor T8 fluorescent lamps are the most efficient light source for
growing plants. I use them, and HPS and MH. The plants seem to like the
3000K fluorescents best, and they are the cheapest way to go.

One thing you have to watch out for with MH is the lumen mainanence. The
lamps get dimmer and dimmer over their lifetime; even worse than
old-technology fluorescents.

Bob

"zxcvbob" wrote in message
...
Timothy wrote:

On Fri, 04 Jul 2003 17:19:18 +0000, Joseph Meehan wrote:


Well maybe not near complete spectrum, but better and may well
be
good enough. It depends on the plants and the stage of their
development.


Red light is generaly assoiciated with flowering and blue light is
generally assoiciated vegetative growth. This can be seen in nature with
spring light (more blue) and summer light (more red). Your not really
ever
going to get true 'full spectrum' from any light source, be it
fluorescent, hps or mh. Some get rather close (grow-lux and ag-grows),
but
no affordable light source will replicate the suns spectrum. The only
light which is almost near sun spectrum is the sulphur type bulbs and
the
led lights. The sulphur bulbs are not ready for market (if they ever
will
be) and are increadibly expensive to make. The led lights are very new
and
expensive for the general consumer. They could turn out to be only as
good
as the fluorescents as far as total lummen out put and intensity, but I
can't afford one to find out.

Some reading material on sulphur lights...
http://www.thekrib.com/Lights/sulphur.html


Triphosphor T8 fluorescent lamps are the most efficient light source for
growing plants. I use them, and HPS and MH. The plants seem to like the
3000K fluorescents best, and they are the cheapest way to go.

One thing you have to watch out for with MH is the lumen mainanence. The
lamps get dimmer and dimmer over their lifetime; even worse than
old-technology fluorescents.

Bob

Actually most commercial applications don't use fluorescents. However I
would agree that they are generally best for most home gardeners.

--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math

Timothy wrote:

On Fri, 04 Jul 2003 17:19:18 +0000, Joseph Meehan wrote:

Well maybe not near complete spectrum, but better and may well
be
good enough. It depends on the plants and the stage of their
development.

Red light is generaly assoiciated with flowering and blue light is
generally assoiciated vegetative growth.

For starting plants, it follows that we can skip the red band.

This can be seen in nature with
spring light (more blue) and summer light (more red). Your not really ever
going to get true 'full spectrum' from any light source, be it
fluorescent, hps or mh. Some get rather close (grow-lux and ag-grows), but
no affordable light source will replicate the suns spectrum. The only
light which is almost near sun spectrum is the sulphur type bulbs and the
led lights. The sulphur bulbs are not ready for market (if they ever will
be) and are increadibly expensive to make. The led lights are very new and
expensive for the general consumer. They could turn out to be only as good
as the fluorescents as far as total lummen out put and intensity, but I
can't afford one to find out.

Some reading material on sulphur lights...
http://www.thekrib.com/Lights/sulphur.html

And even closer to sunlight is actual sunlight. Set the plants out, or
place them beneath a skylight. Install a sun tracking mirror over the
skylight if you have money to burn.