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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 |
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Direct vs. Indirect Light?
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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 |
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Direct vs. Indirect Light?
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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
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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
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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
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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
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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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