Hi all! I have a question about fluorescent lights...

During the winter months I keep most of my orchids inside in a plant cart
with 3 shelves. I will move them outside once temperatures are consistently
over 60 degrees at night (I live in Northeast Florida - Jacksonville).

Each shelf has 2 fluorescent lights above them (48 inches, 40 watts ea). In
an orchid book (Ortho's "All About Orchids") it was recommended to use 4
bulbs per shelf. How critical is the number of bulbs? I would think the
number of bulbs is not as critical as is the actual amount of light.

Do you think that as long as the amount of light as measured by footcandles
is OK, 2 bulbs will suffice?

Thanks.

Larry

4 bulbs allows you to illuminate more plants, or the same number more
brightly, or the same number at the same intensity at a greater distance.

Folks with more experience can provide a better answer, but that's the gist
of it.

--

Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies, Artwork, Books and Lots of Free Info!


"Larry" wrote in message
.. .
Hi all! I have a question about fluorescent lights...

During the winter months I keep most of my orchids inside in a plant cart
with 3 shelves. I will move them outside once temperatures are
consistently over 60 degrees at night (I live in Northeast Florida -
Jacksonville).

Each shelf has 2 fluorescent lights above them (48 inches, 40 watts ea).
In an orchid book (Ortho's "All About Orchids") it was recommended to use
4 bulbs per shelf. How critical is the number of bulbs? I would think the
number of bulbs is not as critical as is the actual amount of light.

Do you think that as long as the amount of light as measured by
footcandles is OK, 2 bulbs will suffice?

Thanks.

Larry

Larry wrote:
Hi all! I have a question about fluorescent lights...

During the winter months I keep most of my orchids inside in a plant cart
with 3 shelves. I will move them outside once temperatures are consistently
over 60 degrees at night (I live in Northeast Florida - Jacksonville).

Each shelf has 2 fluorescent lights above them (48 inches, 40 watts ea). In
an orchid book (Ortho's "All About Orchids") it was recommended to use 4
bulbs per shelf. How critical is the number of bulbs? I would think the
number of bulbs is not as critical as is the actual amount of light.

Do you think that as long as the amount of light as measured by footcandles
is OK, 2 bulbs will suffice?


I don't know how you would get the same number of footcandles from two
tubes as from four. Unless you are changing the distance between the
fixture and the meter. And in my experience, most inexpensive light
meters don't do too good a job on fluorescent light. But that is not
really relevant. What matters is the eternal question "Does it work?".

Since you are growing your plants outdoors for most of the year anyway,
you can probably get away with less than optimal conditions for two or
three months. If your plants don't look stressed, seem to grow OK, and
you are happy with two tubes, then by all means, stick with two tubes.
It has been a few years and a house since I grew under fluorescent
lights, but I was happy with them.

For pure under light growing (in a basement), I found that a four tube
ceiling fixture (2x4' fixture) was just about perfect to illuminate a 2'
wide area (about the width of your usual light cart). 30-35 dollars at
the Home Despot. Two fixtures side by side did a great job on a four
foot x four foot area. That was at a height of about 18", and I was
growing mainly paphs. They loved that little setup, which has since
been retired. Some portions of the growing space were lit by 2 tube
'shoplight' fixtures (four to illuminate a 4 x 4' area). I don't know
that this was any better or worse, the fixtures are cheaper but it leads
to a lot more extension cords.

Oh, and i just used cheap tubes (cool white or warm white). None of
those fancy plant lights. Everything grew fine. For you, since you are
growing outside most of the year, don't spend money on plant tubes.
Spend the extra money on more plants!

Rob

--
Rob's Rules: http://www.msu.edu/~halgren
1) There is always room for one more orchid
2) There is always room for two more orchids
2a) See rule 1
3) When one has insufficient credit to obtain more
orchids, obtain more credit

LittlefrogFarm - Growing the plants Rob likes. )

Thank you for the very thorough reply and recommendations. I was just
surprised by the blanket statement in what I read, indicating that I needed
4 bulbs rather than I needed enough bulbs to provide the right amount of
light.

Larry

"Rob Halgren" wrote in message
...
Larry wrote:
Hi all! I have a question about fluorescent lights...

During the winter months I keep most of my orchids inside in a plant cart
with 3 shelves. I will move them outside once temperatures are
consistently over 60 degrees at night (I live in Northeast Florida -
Jacksonville).

Each shelf has 2 fluorescent lights above them (48 inches, 40 watts ea).
In an orchid book (Ortho's "All About Orchids") it was recommended to use
4 bulbs per shelf. How critical is the number of bulbs? I would think
the number of bulbs is not as critical as is the actual amount of light.

Do you think that as long as the amount of light as measured by
footcandles is OK, 2 bulbs will suffice?


I don't know how you would get the same number of footcandles from two
tubes as from four. Unless you are changing the distance between the
fixture and the meter. And in my experience, most inexpensive light
meters don't do too good a job on fluorescent light. But that is not
really relevant. What matters is the eternal question "Does it work?".

Since you are growing your plants outdoors for most of the year anyway,
you can probably get away with less than optimal conditions for two or
three months. If your plants don't look stressed, seem to grow OK, and
you are happy with two tubes, then by all means, stick with two tubes. It
has been a few years and a house since I grew under fluorescent lights,
but I was happy with them.

For pure under light growing (in a basement), I found that a four tube
ceiling fixture (2x4' fixture) was just about perfect to illuminate a 2'
wide area (about the width of your usual light cart). 30-35 dollars at
the Home Despot. Two fixtures side by side did a great job on a four foot
x four foot area. That was at a height of about 18", and I was growing
mainly paphs. They loved that little setup, which has since been retired.
Some portions of the growing space were lit by 2 tube 'shoplight' fixtures
(four to illuminate a 4 x 4' area). I don't know that this was any better
or worse, the fixtures are cheaper but it leads to a lot more extension
cords.

Oh, and i just used cheap tubes (cool white or warm white). None of those
fancy plant lights. Everything grew fine. For you, since you are growing
outside most of the year, don't spend money on plant tubes. Spend the
extra money on more plants!

Rob

--
Rob's Rules: http://www.msu.edu/~halgren
1) There is always room for one more orchid
2) There is always room for two more orchids
2a) See rule 1
3) When one has insufficient credit to obtain more
orchids, obtain more credit

LittlefrogFarm - Growing the plants Rob likes. )