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Please do not move this thread to the LED thread, so I am not supposed to post there and I do not want my posts edited. Lets keep it civilized :)
Great article about the issues with leds and their intensity.
A New Breed of LED: Intensified Lighting for Indoor Growing
by Brian Chiang and Josh Puckett
2010-08-01
PrintEmailThe Spectral Revolution
In “LED Technology: Paving the Way for a Spectral Revolution” (July Maximum Yield) we discussed how LEDs may transform the way gardeners light their grow rooms. The biggest advantage of advanced LEDs is their ability to deliver wavelength-specific light for plants in different growing conditions.
By mixing various LED chips, a complex and unique light spectrum can be created. Although we know that plants benefit mostly from the blue and red parts of the spectrum, making the best light is not as simple as randomly placing blue and red chips on a panel. There are specific wavelengths that are ideal for plant growth. As research advances, growers will better understand which spectrums can accelerate or slow down growth, improve yields or morph plants. This is only the beginning of the revolution.
Light Intensity Matters
Photosynthesis is the process plants use to convert light into food. In addition to the spectrum of the light received, the intensity of the light also plays a large role in this vital process.
Photosynthesis usually occurs in the leaves of the plants. The green color of the leaves comes from chlorophyll, the pigment that absorbs red and blue light energy and reflects green. Chlorophyll is found in the interior of the leaves in structures called chloroplasts. Light must pass through several layers before it can reach the chlorophyll. Even then, the chlorophyll only serves to harvest the light photons. The photon is passed on from molecule to molecule until it is trapped by photosynthetic reaction centers located deep within the chloroplast. These reaction centers then take the light energy to be used in the photosynthetic process.
Effective LEDs are able to deliver intense light that penetrates down to the lowest levels on a plant.
A reaction center intercepts only around one photon every second, so chlorophyll’s ability to capture light is critical. The more photons there are, the more chances the chlorophyll will have to transfer the photons to a reaction center. This is where light intensity becomes an issue. More intense light means that more photons are being emitted, which increases the probability that a photon will reach a reaction center. Take a simple ring toss for example: the more rings you throw, the higher are your chances that you will hit a target bottle. In the same way, plants benefit from higher light intensity because a higher concentration of photons results in higher photosynthetic productivity.
The “More” Factor
Heat from broadband sources has long limited the amount of light supplied to plants. Such light, including the sun, emits more of the light spectrum than what is required for photosynthesis. Much of this light gives off heat, which is crippling to plant performance if the temperature of the environment is elevated beyond what plants can tolerate. Artificial sunlight sources create heat due to their inefficiency in converting energy from electricity to light. If the lights are placed too close to the grow area, the plants will burn from convection or radiation.
This is not an issue for LEDs. The ability of LEDs to specify wavelengths eliminates the excess light that contributes to unwanted heat. LEDs are a naturally cool light that efficiently converts electricity to light. Growers will be able to place more LEDs over their plants to give that extra boost of light without having to worry about heat.
So what’s the problem?
If this is the case, why haven’t most growers moved on to LEDs? Simply put, some LED grow lights don’t have enough light intensity for photosynthesis to occur. Although LEDs have the capability to specify wavelengths, some LED lights just aren’t manufactured for effective plant growth. These fixtures are built with an LED die placed in a reflective cavity, bonded to two electrical contacts, and then sealed by an epoxy or plastic lens. The LEDs are then assembled by sparsely populating single LED chips over sheet metal and secured in a panel. The goal of this light is to provide broad, widespread light for general illumination purposes, or to use as decorative color changing Christmas lights. However, this bulky packaging limits the amount of LED lights that can be placed over plants, especially when the fixture is almost as large as the grow area! If growers can’t use more LED lights over the grow area, the light intensity issue of these LED fixtures has to be remedied.
General consensus is that LEDs do work, but the overall intensity of the light is not enough. LEDs cannot be used to grow tall plants because of this shallow penetration. Leaves closer to the roots will wither over time. Most LED lights have to work in conjunction with T5 lights, or lower power HID lights in order to be effective.
A New Breed of LED
Now half a century after LEDs were first introduced, a new LED platform is finally here. A scientific breakthrough has resulted in a material that dissipates heat rapidly. When LED chips are placed on this material, they are able to draw heat away quickly and efficiently. This advancement enables LED dies to be placed in close proximity to form a dense “matrix LED” platform. This platform can populate more than 20 LED chips in an area no greater than a dime. What results is directional light that focuses on a much smaller area through an expertly designed reflector. This compact LED provides cool but intense light through this reflector for more photons. In addition, growers can place multiple panels of these lights over their plants. With more light that provides more photons for better photosynthesis, growers can expect a boost in plant performance.
The difference in the two packaging approaches for LEDs is seen in the simple illustration below. The picture demonstrates an analogy using two different nozzles mounted on the same garden hose. On the left, water sprinkles out of many tiny pores from the sunflower-type nozzle. In contrast, the picture on the right shows a single jet of water from an industrial pistol nozzle. The sprayer on the left merely mists the surface of the plants while the steady stream on the right cuts straight down to the soil. Although the amount of water is the same for both hose heads, the nozzle from the right picture is drastically more effective in reaching plant roots.
Let’s apply the garden hose example to LEDs. Imagine the water as light. The typical LED light has tiny chips spread over a wide area similar to the individual holes that water trickles through on the left picture with the sunflower nozzle, and puts out equally weak light. Conversely, imagine if the light has many LED chips densely grouped together to send out an intense beam that behaves like the jet stream shooting out of the pistol nozzle in the right picture. Instead of sprinkling misty light onto the plant’s surface, you would be able to inject light straight down to allow photosynthesis to also happen in the plant’s lower tiers. With more of these lights over a grow area, all parts of the plants will be able to carry out photosynthesis effectively!
LEDs and Tomato Plants
In a lab setting, we tested the effectiveness of this new LED platform over tomato plants in a four by four foot growing area. Six LED lights totaling around 200 watts were hung over nine tomato plants. The lights were scheduled for an 18 hour on and six hour off cycle, and growth of the tomatoes was monitored for two months.
After a month the tomatoes began to flower under the LED lights. The light was able to penetrate down to the lowest levels of the plant, giving the amount of light needed for photosynthesis. In six weeks, the tomatoes began producing fruit even in the bottom tiers of the plant. After two months of testing, the tomato fruits closest to the roots were abundant and healthy.
In a separate experiment, we doubled the intensity of the LED lights to about 400 watts over the tomatoes in their vegetative phase. As with the previous experiment, the testing was done in a controlled four by four foot growing area and closely monitored.
Although the experiment is still in progress, plant growth is evident. Leaves grew wider with a darker green color indicating high levels of chlorophyll even in the lowest tier of the plants. With this added intensity, the tomato plants began to flower in just two weeks. The flowering stage for these tomatoes began early in comparison to the plants in the previous experiment, which began to flower after four weeks. It is clear that these tomato plants benefited from the extra boost of light.
Conclusion
The new dense matrix LED platform revolutionizes the horticulture industry. Growers can now deliver depth penetration that plants need. This advancement provides more intense light, producing tall and healthy plants. LEDs are naturally cool so growers can add even more LEDs to increase the light intensity and supply optimal light to plants. This platform carries plants from vegetation to flowering and fruiting, without the need for additional supplement lighting. The light penetrating capabilities in combination with the spectral offerings of LEDs will give growers even more control over how their plants grow.
Great article about the issues with leds and their intensity.
A New Breed of LED: Intensified Lighting for Indoor Growing
by Brian Chiang and Josh Puckett
2010-08-01
PrintEmailThe Spectral Revolution
In “LED Technology: Paving the Way for a Spectral Revolution” (July Maximum Yield) we discussed how LEDs may transform the way gardeners light their grow rooms. The biggest advantage of advanced LEDs is their ability to deliver wavelength-specific light for plants in different growing conditions.
By mixing various LED chips, a complex and unique light spectrum can be created. Although we know that plants benefit mostly from the blue and red parts of the spectrum, making the best light is not as simple as randomly placing blue and red chips on a panel. There are specific wavelengths that are ideal for plant growth. As research advances, growers will better understand which spectrums can accelerate or slow down growth, improve yields or morph plants. This is only the beginning of the revolution.
Light Intensity Matters
Photosynthesis is the process plants use to convert light into food. In addition to the spectrum of the light received, the intensity of the light also plays a large role in this vital process.
Photosynthesis usually occurs in the leaves of the plants. The green color of the leaves comes from chlorophyll, the pigment that absorbs red and blue light energy and reflects green. Chlorophyll is found in the interior of the leaves in structures called chloroplasts. Light must pass through several layers before it can reach the chlorophyll. Even then, the chlorophyll only serves to harvest the light photons. The photon is passed on from molecule to molecule until it is trapped by photosynthetic reaction centers located deep within the chloroplast. These reaction centers then take the light energy to be used in the photosynthetic process.
Effective LEDs are able to deliver intense light that penetrates down to the lowest levels on a plant.
A reaction center intercepts only around one photon every second, so chlorophyll’s ability to capture light is critical. The more photons there are, the more chances the chlorophyll will have to transfer the photons to a reaction center. This is where light intensity becomes an issue. More intense light means that more photons are being emitted, which increases the probability that a photon will reach a reaction center. Take a simple ring toss for example: the more rings you throw, the higher are your chances that you will hit a target bottle. In the same way, plants benefit from higher light intensity because a higher concentration of photons results in higher photosynthetic productivity.
The “More” Factor
Heat from broadband sources has long limited the amount of light supplied to plants. Such light, including the sun, emits more of the light spectrum than what is required for photosynthesis. Much of this light gives off heat, which is crippling to plant performance if the temperature of the environment is elevated beyond what plants can tolerate. Artificial sunlight sources create heat due to their inefficiency in converting energy from electricity to light. If the lights are placed too close to the grow area, the plants will burn from convection or radiation.
This is not an issue for LEDs. The ability of LEDs to specify wavelengths eliminates the excess light that contributes to unwanted heat. LEDs are a naturally cool light that efficiently converts electricity to light. Growers will be able to place more LEDs over their plants to give that extra boost of light without having to worry about heat.
So what’s the problem?
If this is the case, why haven’t most growers moved on to LEDs? Simply put, some LED grow lights don’t have enough light intensity for photosynthesis to occur. Although LEDs have the capability to specify wavelengths, some LED lights just aren’t manufactured for effective plant growth. These fixtures are built with an LED die placed in a reflective cavity, bonded to two electrical contacts, and then sealed by an epoxy or plastic lens. The LEDs are then assembled by sparsely populating single LED chips over sheet metal and secured in a panel. The goal of this light is to provide broad, widespread light for general illumination purposes, or to use as decorative color changing Christmas lights. However, this bulky packaging limits the amount of LED lights that can be placed over plants, especially when the fixture is almost as large as the grow area! If growers can’t use more LED lights over the grow area, the light intensity issue of these LED fixtures has to be remedied.
General consensus is that LEDs do work, but the overall intensity of the light is not enough. LEDs cannot be used to grow tall plants because of this shallow penetration. Leaves closer to the roots will wither over time. Most LED lights have to work in conjunction with T5 lights, or lower power HID lights in order to be effective.
A New Breed of LED
Now half a century after LEDs were first introduced, a new LED platform is finally here. A scientific breakthrough has resulted in a material that dissipates heat rapidly. When LED chips are placed on this material, they are able to draw heat away quickly and efficiently. This advancement enables LED dies to be placed in close proximity to form a dense “matrix LED” platform. This platform can populate more than 20 LED chips in an area no greater than a dime. What results is directional light that focuses on a much smaller area through an expertly designed reflector. This compact LED provides cool but intense light through this reflector for more photons. In addition, growers can place multiple panels of these lights over their plants. With more light that provides more photons for better photosynthesis, growers can expect a boost in plant performance.
The difference in the two packaging approaches for LEDs is seen in the simple illustration below. The picture demonstrates an analogy using two different nozzles mounted on the same garden hose. On the left, water sprinkles out of many tiny pores from the sunflower-type nozzle. In contrast, the picture on the right shows a single jet of water from an industrial pistol nozzle. The sprayer on the left merely mists the surface of the plants while the steady stream on the right cuts straight down to the soil. Although the amount of water is the same for both hose heads, the nozzle from the right picture is drastically more effective in reaching plant roots.
Let’s apply the garden hose example to LEDs. Imagine the water as light. The typical LED light has tiny chips spread over a wide area similar to the individual holes that water trickles through on the left picture with the sunflower nozzle, and puts out equally weak light. Conversely, imagine if the light has many LED chips densely grouped together to send out an intense beam that behaves like the jet stream shooting out of the pistol nozzle in the right picture. Instead of sprinkling misty light onto the plant’s surface, you would be able to inject light straight down to allow photosynthesis to also happen in the plant’s lower tiers. With more of these lights over a grow area, all parts of the plants will be able to carry out photosynthesis effectively!
LEDs and Tomato Plants
In a lab setting, we tested the effectiveness of this new LED platform over tomato plants in a four by four foot growing area. Six LED lights totaling around 200 watts were hung over nine tomato plants. The lights were scheduled for an 18 hour on and six hour off cycle, and growth of the tomatoes was monitored for two months.
After a month the tomatoes began to flower under the LED lights. The light was able to penetrate down to the lowest levels of the plant, giving the amount of light needed for photosynthesis. In six weeks, the tomatoes began producing fruit even in the bottom tiers of the plant. After two months of testing, the tomato fruits closest to the roots were abundant and healthy.
In a separate experiment, we doubled the intensity of the LED lights to about 400 watts over the tomatoes in their vegetative phase. As with the previous experiment, the testing was done in a controlled four by four foot growing area and closely monitored.
Although the experiment is still in progress, plant growth is evident. Leaves grew wider with a darker green color indicating high levels of chlorophyll even in the lowest tier of the plants. With this added intensity, the tomato plants began to flower in just two weeks. The flowering stage for these tomatoes began early in comparison to the plants in the previous experiment, which began to flower after four weeks. It is clear that these tomato plants benefited from the extra boost of light.
Conclusion
The new dense matrix LED platform revolutionizes the horticulture industry. Growers can now deliver depth penetration that plants need. This advancement provides more intense light, producing tall and healthy plants. LEDs are naturally cool so growers can add even more LEDs to increase the light intensity and supply optimal light to plants. This platform carries plants from vegetation to flowering and fruiting, without the need for additional supplement lighting. The light penetrating capabilities in combination with the spectral offerings of LEDs will give growers even more control over how their plants grow.
