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Old 21-08-2003, 12:22 PM
 
Posts: n/a
Default Direct vs. Indirect Light?

YANQ - Yet Another Newbie Question

Is direct light essential?

It's a little hard for me to find growing info appropriate to my
situation (South-facing open, hard-roofed, second-floor balcony right
on Tampa Bay in St. Petersburg, Florida), so I thought I'd go talk to
one of the local purveyors. This particular place (Art Stone Company,
for any locals) has been there for years and is clearly the result of
hobby-gone-wild. Point is just that I assume the guy is fairly
knowledgeable.

Light levels in the shade are 500-2000 footcandles, depending on how
close you are to the front. Light levels out by the railing are, of
course, Florida-level, at 12-16000 footcandles. I also took
measurements in his greenhouse and the numbers were similar. His
brightest areas were a bit brighter than my brightest, and his darkest
were darker than mine, but all-in-all, quite comparable.

And yet, when I described my growing situation, which is this
hard-roof balcony, he seemed fairly pessimistic. I didn't have the
numbers in footcandles at that point, but I said the numbers were
about the same as home. He said that the indirect light didn't count
as much, and that my light levels were quite low. He advised Phals,
and said that while other orchids would grow, they would be unlikely
to bloom.

I've had a few orchids growing here for some months now and the leaves
have not gone dark green. No blooming, but that's as likely due to
other aspects of newbie husbandry.

So, what's the scoop? Is the guy right? I'll tell ya, for a
roofed-over porch, it's pretty bright! I actually had to move one
Phal back towards the back wall, as the leaves lightened up a lot.

Is direct light essential? As long as I get the light levels required
on the meter, is that "good enough" or not?

TIA

Gannet
St. Petersburg, Florida
  #3   Report Post  
Old 21-08-2003, 12:42 PM
 
Posts: n/a
Default Direct vs. Indirect Light?

Geir Harris Hedemark wrote:
Light meters are (unless you have a professional, calibrated version)
notoriously unreliable.


This is a quality professional photographer's lightmeter. It's quite
accurate, and I know how to use it to get accurate results (one of my
past hobbies).

Gannet
  #5   Report Post  
Old 21-08-2003, 01:02 PM
Wendy
 
Posts: n/a
Default Direct vs. Indirect Light?

Hi Gannet, If you walk into a forest & a tree falls,........will you see the
light? *G*
I am not that savvy when it comes to foot candles but I would say the guy is
correct!
In order to grow the higher light requiring plants you would need an open
roof with shade cloth.
I was told to hold your hand about 18" above the plant & you should see a
slight shadow.
I would think you need direct shaded sun 'rays' the entire day.
Having said all this, I have Vandas (high lighters) that face south east,
that bloom. They are
shaded by the house from about 3pm onwards?
Cheers Wendy....Just my tickies worth.
wrote in message
...
YANQ - Yet Another Newbie Question

Is direct light essential?

It's a little hard for me to find growing info appropriate to my
situation (South-facing open, hard-roofed, second-floor balcony right
on Tampa Bay in St. Petersburg, Florida), so I thought I'd go talk to
one of the local purveyors. This particular place (Art Stone Company,
for any locals) has been there for years and is clearly the result of
hobby-gone-wild. Point is just that I assume the guy is fairly
knowledgeable.

Light levels in the shade are 500-2000 footcandles, depending on how
close you are to the front. Light levels out by the railing are, of
course, Florida-level, at 12-16000 footcandles. I also took
measurements in his greenhouse and the numbers were similar. His
brightest areas were a bit brighter than my brightest, and his darkest
were darker than mine, but all-in-all, quite comparable.

And yet, when I described my growing situation, which is this
hard-roof balcony, he seemed fairly pessimistic. I didn't have the
numbers in footcandles at that point, but I said the numbers were
about the same as home. He said that the indirect light didn't count
as much, and that my light levels were quite low. He advised Phals,
and said that while other orchids would grow, they would be unlikely
to bloom.

I've had a few orchids growing here for some months now and the leaves
have not gone dark green. No blooming, but that's as likely due to
other aspects of newbie husbandry.

So, what's the scoop? Is the guy right? I'll tell ya, for a
roofed-over porch, it's pretty bright! I actually had to move one
Phal back towards the back wall, as the leaves lightened up a lot.

Is direct light essential? As long as I get the light levels required
on the meter, is that "good enough" or not?

TIA

Gannet
St. Petersburg, Florida





  #6   Report Post  
Old 21-08-2003, 02:32 PM
Al
 
Posts: n/a
Default Direct vs. Indirect Light?

My horticulture teacher told me that 'full sun' was defined as 5 hours a day
or more of direct sunlight. Maybe this was just an 'off the cuff'
definition but it helps one to keep in mind that the light requirement to
flower a plant is more than just intensity (foot candles) it is also
duration. A single foot candle measurement gives you only part of the
story.

Direct sunlight for 5 hours in Florida may be essential to some very high
light level plants, like Vanda if you want them to bloom. Direct sunlight
on Vandas may not be enough to get them to bloom if this sun light falls on
them at the north pole for 24 hours a day. :-)

Direct sunlight on a Phal in my growing environment only works in the winter
when intensity is off by 30% of the summer high and then only in the early
or late parts of the day when the angle is very great and then only for a
matter of minutes rather than hours. Air temperature and relative humidity
also plays a role in how much direct light can fall on their leaves without
causing them to burn, I think.

Light, direct or indirect, must be of a certain intensity and wave length to
excite the chlorophyll molecules to do their job. And this intensity and
correct wave length has to occur for a certain amount of uninterrupted time
in a 24 hour cycle. If you are using the sun light, the wave length is not
going to be a problem. Low intensity can be somewhat offset by increased
duration. This is why people using artificial lights which are typically
lower in intensity than natural lights use increased duration. Decreased
duration can allow increased intensity. Think of sunlight filtered through
gently moving leaves from the tree branches above an orchid plant. Here
very direct light falls on the orchid but only briefly and never for so long
as to cause the leaves to overheat and burn before the shadow of the
filtering leaves causes the intensity to decrease.

"Indirect vs. direct" may be just your friend's way of looking at the
gestalt in his growing environment to help him make sense of his
observations and to communicate them to you.

Eventually, as you progress in this hobby, you will learn to let the plants
themselves tell you what light levels they want. And they are all
individuals in their needs. You are already well on your way to this
realization because you are watching the leaf color. Also watch for
relative tissue thickness, relative strength of new growths, stem length,
flower color intensity, etc...

There are a lot of factors involved in blooming too, obviously. Not just
light intensity. If your plants are mature and all other aspects of your
culture are correct for them, you should see blooming over the course of a
year or so sufficient for you to determine if the light levels and duration
are good. A few months of observation is probably not enough time for you
to know yet if you are on the right track.

The assumption here is also that if the plant flowers it must be grown
correctly, with the 'right' light levels, proper temperature, etc... :-)
In addition to flowering on a regular schedule, also look for proper light
levels to help the whole plant to increase itself. A plant which gets good
enough light to bloom every year but still limps along without making side
shoots or multiple leads may not be really getting the light levels it
wants. Of course this is all relative to the vigor of the individual plant
in question.

Wendy" wrote in message
news:Uv21b.28917$kP.21191@fed1read03...
Hi Gannet, If you walk into a forest & a tree falls,........will you see

the
light? *G*
I am not that savvy when it comes to foot candles but I would say the guy

is
correct!
In order to grow the higher light requiring plants you would need an open
roof with shade cloth.
I was told to hold your hand about 18" above the plant & you should see a
slight shadow.
I would think you need direct shaded sun 'rays' the entire day.
Having said all this, I have Vandas (high lighters) that face south east,
that bloom. They are
shaded by the house from about 3pm onwards?
Cheers Wendy....Just my tickies worth.
wrote in message
...
YANQ - Yet Another Newbie Question

Is direct light essential?

It's a little hard for me to find growing info appropriate to my
situation (South-facing open, hard-roofed, second-floor balcony right
on Tampa Bay in St. Petersburg, Florida), so I thought I'd go talk to
one of the local purveyors. This particular place (Art Stone Company,
for any locals) has been there for years and is clearly the result of
hobby-gone-wild. Point is just that I assume the guy is fairly
knowledgeable.

Light levels in the shade are 500-2000 footcandles, depending on how
close you are to the front. Light levels out by the railing are, of
course, Florida-level, at 12-16000 footcandles. I also took
measurements in his greenhouse and the numbers were similar. His
brightest areas were a bit brighter than my brightest, and his darkest
were darker than mine, but all-in-all, quite comparable.

And yet, when I described my growing situation, which is this
hard-roof balcony, he seemed fairly pessimistic. I didn't have the
numbers in footcandles at that point, but I said the numbers were
about the same as home. He said that the indirect light didn't count
as much, and that my light levels were quite low. He advised Phals,
and said that while other orchids would grow, they would be unlikely
to bloom.

I've had a few orchids growing here for some months now and the leaves
have not gone dark green. No blooming, but that's as likely due to
other aspects of newbie husbandry.

So, what's the scoop? Is the guy right? I'll tell ya, for a
roofed-over porch, it's pretty bright! I actually had to move one
Phal back towards the back wall, as the leaves lightened up a lot.

Is direct light essential? As long as I get the light levels required
on the meter, is that "good enough" or not?

TIA

Gannet
St. Petersburg, Florida





  #7   Report Post  
Old 21-08-2003, 04:02 PM
Wendy
 
Posts: n/a
Default Direct vs. Indirect Light?

Very good answer Al, I love reading your 'stuff' (for lack of a better
work), you should retire & write books.
But Gannet has a hard covered roof so wouldn't he have a period of time with
no rays?
Now I have another question, could you use mirrors to deflect the sunlight?
Cheers Wendy
"Al" wrote in message
...
My horticulture teacher told me that 'full sun' was defined as 5 hours a

day
or more of direct sunlight. Maybe this was just an 'off the cuff'
definition but it helps one to keep in mind that the light requirement to
flower a plant is more than just intensity (foot candles) it is also
duration. A single foot candle measurement gives you only part of the
story.

Direct sunlight for 5 hours in Florida may be essential to some very high
light level plants, like Vanda if you want them to bloom. Direct sunlight
on Vandas may not be enough to get them to bloom if this sun light falls

on
them at the north pole for 24 hours a day. :-)

Direct sunlight on a Phal in my growing environment only works in the

winter
when intensity is off by 30% of the summer high and then only in the early
or late parts of the day when the angle is very great and then only for a
matter of minutes rather than hours. Air temperature and relative

humidity
also plays a role in how much direct light can fall on their leaves

without
causing them to burn, I think.

Light, direct or indirect, must be of a certain intensity and wave length

to
excite the chlorophyll molecules to do their job. And this intensity and
correct wave length has to occur for a certain amount of uninterrupted

time
in a 24 hour cycle. If you are using the sun light, the wave length is

not
going to be a problem. Low intensity can be somewhat offset by increased
duration. This is why people using artificial lights which are typically
lower in intensity than natural lights use increased duration. Decreased
duration can allow increased intensity. Think of sunlight filtered

through
gently moving leaves from the tree branches above an orchid plant. Here
very direct light falls on the orchid but only briefly and never for so

long
as to cause the leaves to overheat and burn before the shadow of the
filtering leaves causes the intensity to decrease.

"Indirect vs. direct" may be just your friend's way of looking at the
gestalt in his growing environment to help him make sense of his
observations and to communicate them to you.

Eventually, as you progress in this hobby, you will learn to let the

plants
themselves tell you what light levels they want. And they are all
individuals in their needs. You are already well on your way to this
realization because you are watching the leaf color. Also watch for
relative tissue thickness, relative strength of new growths, stem length,
flower color intensity, etc...

There are a lot of factors involved in blooming too, obviously. Not just
light intensity. If your plants are mature and all other aspects of your
culture are correct for them, you should see blooming over the course of a
year or so sufficient for you to determine if the light levels and

duration
are good. A few months of observation is probably not enough time for you
to know yet if you are on the right track.

The assumption here is also that if the plant flowers it must be grown
correctly, with the 'right' light levels, proper temperature, etc... :-)
In addition to flowering on a regular schedule, also look for proper light
levels to help the whole plant to increase itself. A plant which gets

good
enough light to bloom every year but still limps along without making side
shoots or multiple leads may not be really getting the light levels it
wants. Of course this is all relative to the vigor of the individual

plant
in question.

Wendy" wrote in message
news:Uv21b.28917$kP.21191@fed1read03...
Hi Gannet, If you walk into a forest & a tree falls,........will you see

the
light? *G*
I am not that savvy when it comes to foot candles but I would say the

guy
is
correct!
In order to grow the higher light requiring plants you would need an

open
roof with shade cloth.
I was told to hold your hand about 18" above the plant & you should see

a
slight shadow.
I would think you need direct shaded sun 'rays' the entire day.
Having said all this, I have Vandas (high lighters) that face south

east,
that bloom. They are
shaded by the house from about 3pm onwards?
Cheers Wendy....Just my tickies worth.
wrote in message
...
YANQ - Yet Another Newbie Question

Is direct light essential?

It's a little hard for me to find growing info appropriate to my
situation (South-facing open, hard-roofed, second-floor balcony right
on Tampa Bay in St. Petersburg, Florida), so I thought I'd go talk to
one of the local purveyors. This particular place (Art Stone Company,
for any locals) has been there for years and is clearly the result of
hobby-gone-wild. Point is just that I assume the guy is fairly
knowledgeable.

Light levels in the shade are 500-2000 footcandles, depending on how
close you are to the front. Light levels out by the railing are, of
course, Florida-level, at 12-16000 footcandles. I also took
measurements in his greenhouse and the numbers were similar. His
brightest areas were a bit brighter than my brightest, and his darkest
were darker than mine, but all-in-all, quite comparable.

And yet, when I described my growing situation, which is this
hard-roof balcony, he seemed fairly pessimistic. I didn't have the
numbers in footcandles at that point, but I said the numbers were
about the same as home. He said that the indirect light didn't count
as much, and that my light levels were quite low. He advised Phals,
and said that while other orchids would grow, they would be unlikely
to bloom.

I've had a few orchids growing here for some months now and the leaves
have not gone dark green. No blooming, but that's as likely due to
other aspects of newbie husbandry.

So, what's the scoop? Is the guy right? I'll tell ya, for a
roofed-over porch, it's pretty bright! I actually had to move one
Phal back towards the back wall, as the leaves lightened up a lot.

Is direct light essential? As long as I get the light levels required
on the meter, is that "good enough" or not?

TIA

Gannet
St. Petersburg, Florida







  #8   Report Post  
Old 21-08-2003, 04:42 PM
Al
 
Posts: n/a
Default Direct vs. Indirect Light?

Vandas under a covered roof that are not receiving direct sun may not bloom
well in the long run. They really do need a lot of light. Phals on the
other hand require much less light. If I heard this environment described
without seeing it I might also say that Phals were a better choice than
Vandas. Buzz words like 'covered' would rule out recommending Vandas
anyway, at least by my way of thinking. However, the size of the covering
and the amount of reflective surfaces around the covered area, like concrete
floors, white painted brick walls, water from the bay, mirrors, :-) etc,
will determine how much ambient indirect light really reaches under the
covering to the plants there. Since, as he has already mentioned he had to
move a Phal to a less bright location furthur under the covering, I feel
safe to say he has enough light to bloom Phals and probably cattleya. If
he were to put his vanda plants right at the edge of his south facing
balcony he will probably see them flower, don't you think? Of course, he
could conceivably shade the Phals behind them so completely with Vandas
around the outskirts of the covering that the poor Phal it might not have
enough light any longer.

" wrote in message news:CX41b.30133$kP.185@fed1read03...
Very good answer Al, I love reading your 'stuff' (for lack of a better
work), you should retire & write books.
But Gannet has a hard covered roof so wouldn't he have a period of time

with
no rays?
Now I have another question, could you use mirrors to deflect the

sunlight?
Cheers Wendy
"Al" wrote in message
...
My horticulture teacher told me that 'full sun' was defined as 5 hours a

day
or more of direct sunlight. Maybe this was just an 'off the cuff'
definition but it helps one to keep in mind that the light requirement

to
flower a plant is more than just intensity (foot candles) it is also
duration. A single foot candle measurement gives you only part of the
story.

Direct sunlight for 5 hours in Florida may be essential to some very

high
light level plants, like Vanda if you want them to bloom. Direct

sunlight
on Vandas may not be enough to get them to bloom if this sun light falls

on
them at the north pole for 24 hours a day. :-)

Direct sunlight on a Phal in my growing environment only works in the

winter
when intensity is off by 30% of the summer high and then only in the

early
or late parts of the day when the angle is very great and then only for

a
matter of minutes rather than hours. Air temperature and relative

humidity
also plays a role in how much direct light can fall on their leaves

without
causing them to burn, I think.

Light, direct or indirect, must be of a certain intensity and wave

length
to
excite the chlorophyll molecules to do their job. And this intensity

and
correct wave length has to occur for a certain amount of uninterrupted

time
in a 24 hour cycle. If you are using the sun light, the wave length is

not
going to be a problem. Low intensity can be somewhat offset by

increased
duration. This is why people using artificial lights which are

typically
lower in intensity than natural lights use increased duration.

Decreased
duration can allow increased intensity. Think of sunlight filtered

through
gently moving leaves from the tree branches above an orchid plant. Here
very direct light falls on the orchid but only briefly and never for so

long
as to cause the leaves to overheat and burn before the shadow of the
filtering leaves causes the intensity to decrease.

"Indirect vs. direct" may be just your friend's way of looking at the
gestalt in his growing environment to help him make sense of his
observations and to communicate them to you.

Eventually, as you progress in this hobby, you will learn to let the

plants
themselves tell you what light levels they want. And they are all
individuals in their needs. You are already well on your way to this
realization because you are watching the leaf color. Also watch for
relative tissue thickness, relative strength of new growths, stem

length,
flower color intensity, etc...

There are a lot of factors involved in blooming too, obviously. Not

just
light intensity. If your plants are mature and all other aspects of

your
culture are correct for them, you should see blooming over the course of

a
year or so sufficient for you to determine if the light levels and

duration
are good. A few months of observation is probably not enough time for

you
to know yet if you are on the right track.

The assumption here is also that if the plant flowers it must be grown
correctly, with the 'right' light levels, proper temperature, etc...

:-)
In addition to flowering on a regular schedule, also look for proper

light
levels to help the whole plant to increase itself. A plant which gets

good
enough light to bloom every year but still limps along without making

side
shoots or multiple leads may not be really getting the light levels it
wants. Of course this is all relative to the vigor of the individual

plant
in question.

Wendy" wrote in message
news:Uv21b.28917$kP.21191@fed1read03...
Hi Gannet, If you walk into a forest & a tree falls,........will you

see
the
light? *G*
I am not that savvy when it comes to foot candles but I would say the

guy
is
correct!
In order to grow the higher light requiring plants you would need an

open
roof with shade cloth.
I was told to hold your hand about 18" above the plant & you should

see
a
slight shadow.
I would think you need direct shaded sun 'rays' the entire day.
Having said all this, I have Vandas (high lighters) that face south

east,
that bloom. They are
shaded by the house from about 3pm onwards?
Cheers Wendy....Just my tickies worth.
wrote in message
...
YANQ - Yet Another Newbie Question

Is direct light essential?

It's a little hard for me to find growing info appropriate to my
situation (South-facing open, hard-roofed, second-floor balcony

right
on Tampa Bay in St. Petersburg, Florida), so I thought I'd go talk

to
one of the local purveyors. This particular place (Art Stone

Company,
for any locals) has been there for years and is clearly the result

of
hobby-gone-wild. Point is just that I assume the guy is fairly
knowledgeable.

Light levels in the shade are 500-2000 footcandles, depending on how
close you are to the front. Light levels out by the railing are, of
course, Florida-level, at 12-16000 footcandles. I also took
measurements in his greenhouse and the numbers were similar. His
brightest areas were a bit brighter than my brightest, and his

darkest
were darker than mine, but all-in-all, quite comparable.

And yet, when I described my growing situation, which is this
hard-roof balcony, he seemed fairly pessimistic. I didn't have the
numbers in footcandles at that point, but I said the numbers were
about the same as home. He said that the indirect light didn't

count
as much, and that my light levels were quite low. He advised Phals,
and said that while other orchids would grow, they would be unlikely
to bloom.

I've had a few orchids growing here for some months now and the

leaves
have not gone dark green. No blooming, but that's as likely due to
other aspects of newbie husbandry.

So, what's the scoop? Is the guy right? I'll tell ya, for a
roofed-over porch, it's pretty bright! I actually had to move one
Phal back towards the back wall, as the leaves lightened up a lot.

Is direct light essential? As long as I get the light levels

required
on the meter, is that "good enough" or not?

TIA

Gannet
St. Petersburg, Florida








  #9   Report Post  
Old 22-08-2003, 08:02 AM
Bolero
 
Posts: n/a
Default Direct vs. Indirect Light?

Yes some direct light is really necessary.

Direct light under shade cloth would be better but I have heard of one guy
(magazine article) here who puts his orchids in direct sun for 15 to 30
minutes a day, actually rotates them in direct light and then puts them back
in the shade and he gets better blooms than he ever has.

Maybe you could opt for that?

wrote in message
...
YANQ - Yet Another Newbie Question

Is direct light essential?

It's a little hard for me to find growing info appropriate to my
situation (South-facing open, hard-roofed, second-floor balcony right
on Tampa Bay in St. Petersburg, Florida), so I thought I'd go talk to
one of the local purveyors. This particular place (Art Stone Company,
for any locals) has been there for years and is clearly the result of
hobby-gone-wild. Point is just that I assume the guy is fairly
knowledgeable.

Light levels in the shade are 500-2000 footcandles, depending on how
close you are to the front. Light levels out by the railing are, of
course, Florida-level, at 12-16000 footcandles. I also took
measurements in his greenhouse and the numbers were similar. His
brightest areas were a bit brighter than my brightest, and his darkest
were darker than mine, but all-in-all, quite comparable.

And yet, when I described my growing situation, which is this
hard-roof balcony, he seemed fairly pessimistic. I didn't have the
numbers in footcandles at that point, but I said the numbers were
about the same as home. He said that the indirect light didn't count
as much, and that my light levels were quite low. He advised Phals,
and said that while other orchids would grow, they would be unlikely
to bloom.

I've had a few orchids growing here for some months now and the leaves
have not gone dark green. No blooming, but that's as likely due to
other aspects of newbie husbandry.

So, what's the scoop? Is the guy right? I'll tell ya, for a
roofed-over porch, it's pretty bright! I actually had to move one
Phal back towards the back wall, as the leaves lightened up a lot.

Is direct light essential? As long as I get the light levels required
on the meter, is that "good enough" or not?

TIA

Gannet
St. Petersburg, Florida



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