We were talking about LED's in tube cathodes, and then high powered LED's and grow lights were mentioned.
I've been playing w/ high powered LED's for aquarium lighting for several years, and last fall built some grow lights out of spare LED's.
I used bridgelux emitters. They were left over from the aquarium project, so I had various shades of white. They're high powered emitters. I've got ~50 watt and ~20 watt emitters. I liked the point source of light for my aquarium, rather than having smaller emitters spread out over the canopy, so that's why I used those. A bunch of smaller emitters is definitely more efficient than having all 50 watts packed into a small area.
I've found for terrestrial plants, the emitters w/ the most red in the spectrum work best. Generally low kelvin numbers. They're less efficient than the cool emitters, but plants have done much better under them.
I used about 315 watts of HPS and MH in previous years to overwinter a bunch of peppers and a lime tree. Last year I used 90 watts of LED, and the plants did just as well.
I generally use a 50 watt compact fluorescent fixture (long tube, not the coils for home lighting) over each seedling tray in the early spring. This year I used a 20 watt LED over one tray. The LED tray looked like the plants were in the sun, compared the the thin lanky plants under the fluorescent.
The bridgelux emitters I've got want about 19v at 1A, and that's perfect for an old laptop power brick (Which I get for free). I use a CCS after the laptop power supply.
I've been playing w/ high powered LED's for aquarium lighting for several years, and last fall built some grow lights out of spare LED's.
I used bridgelux emitters. They were left over from the aquarium project, so I had various shades of white. They're high powered emitters. I've got ~50 watt and ~20 watt emitters. I liked the point source of light for my aquarium, rather than having smaller emitters spread out over the canopy, so that's why I used those. A bunch of smaller emitters is definitely more efficient than having all 50 watts packed into a small area.
I've found for terrestrial plants, the emitters w/ the most red in the spectrum work best. Generally low kelvin numbers. They're less efficient than the cool emitters, but plants have done much better under them.
I used about 315 watts of HPS and MH in previous years to overwinter a bunch of peppers and a lime tree. Last year I used 90 watts of LED, and the plants did just as well.
I generally use a 50 watt compact fluorescent fixture (long tube, not the coils for home lighting) over each seedling tray in the early spring. This year I used a 20 watt LED over one tray. The LED tray looked like the plants were in the sun, compared the the thin lanky plants under the fluorescent.
The bridgelux emitters I've got want about 19v at 1A, and that's perfect for an old laptop power brick (Which I get for free). I use a CCS after the laptop power supply.
What would you use for growing live freshwater aquarium plants? I've been out of the aquarium hobby for some years, but the planted tanks I have had were my favorites.
Bill
Bill
I've got a small reef, and over that I have a big 50w warm white emitter , surrounded by a bunch of smaller 3w blue and royal blue. I'm trying to find someone to take my little reef tank, as I don't really have the time for it anymore.
I've got a big 220 gallon freshwater planted tank.. Co2 injection. Soil substrate, w/ a gravel 'lid' over the dirt. I love it! Fish are super happy in it. The freshwater plants like the warm white light. (they're basically the same as terrestrial plants). I've got a few of the 20 watt warm white emitters, and still a 10,000k MH 150watt bulb. Eventually the MH will get replaced w/ another ~20 watt white emitter, and a few blue and red emitters to fill out the spectrum.
I've got a big 220 gallon freshwater planted tank.. Co2 injection. Soil substrate, w/ a gravel 'lid' over the dirt. I love it! Fish are super happy in it. The freshwater plants like the warm white light. (they're basically the same as terrestrial plants). I've got a few of the 20 watt warm white emitters, and still a 10,000k MH 150watt bulb. Eventually the MH will get replaced w/ another ~20 watt white emitter, and a few blue and red emitters to fill out the spectrum.
I have for about 7 years been experimenting with domestic room lighting using LEDs.
The first was 9 Luxon stars in an array to replace an unreliable strip light. This has been very reliable with a power brick from a cash register.
The best reliability will be a laminated transformer with a bucking coil in series with the rectifier to get rid of the charging pulses from the capacitor to keep the core cool. This may not be the most efficient thing in the world but the trouble involved with replacing the power brick every two years is worth the extra energy cost and electronic waste saving will also save on waste removal tax in the long run.
I have been looking into growing plants under LEDs and need someone whom is growing high profit plantings whom will allow me on site to measure what the leaves actually absorb or not.
This will mean that some parts of the spectrum can be left out saving further energy and equipment costs.
The first was 9 Luxon stars in an array to replace an unreliable strip light. This has been very reliable with a power brick from a cash register.
The best reliability will be a laminated transformer with a bucking coil in series with the rectifier to get rid of the charging pulses from the capacitor to keep the core cool. This may not be the most efficient thing in the world but the trouble involved with replacing the power brick every two years is worth the extra energy cost and electronic waste saving will also save on waste removal tax in the long run.
I have been looking into growing plants under LEDs and need someone whom is growing high profit plantings whom will allow me on site to measure what the leaves actually absorb or not.
This will mean that some parts of the spectrum can be left out saving further energy and equipment costs.
There's plenty of data about what spectrum you need for plants.. Most of the info is on MJ growing forums, but they are serious about it, and some good data can be found. A couple companies make red emitters at the correct wavelength (normal red led's work, but are a bit too high in the spectrum), and the blue is easy to find.
I haven't tried focusing on the blue and red spectrum yet, but that was my initial plan. I just had all these white emitters left over, so used them, and have been happy w/ the results.
Actually, I still have some links saved in my bookmarks..
http://shop.stevesleds.com/Philips-Luxeon-ES-Deep-Red-3-Watt-LEDs-Luxeon-ES-Deep-Red.htm
http://www.ledgroupbuy.com/deep-red-660nm/
I haven't tried focusing on the blue and red spectrum yet, but that was my initial plan. I just had all these white emitters left over, so used them, and have been happy w/ the results.
Actually, I still have some links saved in my bookmarks..
http://shop.stevesleds.com/Philips-Luxeon-ES-Deep-Red-3-Watt-LEDs-Luxeon-ES-Deep-Red.htm
http://www.ledgroupbuy.com/deep-red-660nm/
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I start my sets for the garden around mid February. I've been using "Gro-Lux" FLs with good success, but the idea of using LEDs is interesting in that it might offer better height adjustment as the seedlings grow.
The LEDS have another advantage in that they emit very little UV, so insects are not attracted to the lights.
The LEDS have another advantage in that they emit very little UV, so insects are not attracted to the lights.
So with the data provided it looks as though chlorophyll A is at highest absorption around 425nm where chlorophyll B is closer to 470nm. They both are absorbed to a lesser degree at 650nm for chlorophyll B and 675nm for chlorophyll A.
This is quoted University of Massachusetts article:
"The vital rays for plant growth are blue-light at 450 nm, red light at 650 nm, and far-red light at 730 nm. The 450 and 650 nm rays are required for plant photosynthesis, the production of food from light, water, carbon dioxide through the catalytic action of the plant pigment, chlorophyll. The 650 and 730 nm wavelengths control flowering through light-induced changes in the plant pigment, phytochrome."
Here is a link to the full article.
Univeristy of Massachusetts Amherst:Course Homepage:Template
This is quoted University of Massachusetts article:
"The vital rays for plant growth are blue-light at 450 nm, red light at 650 nm, and far-red light at 730 nm. The 450 and 650 nm rays are required for plant photosynthesis, the production of food from light, water, carbon dioxide through the catalytic action of the plant pigment, chlorophyll. The 650 and 730 nm wavelengths control flowering through light-induced changes in the plant pigment, phytochrome."
Here is a link to the full article.
Univeristy of Massachusetts Amherst:Course Homepage:Template
Attachments
Another is that all the light is emitted down towards the plant. You don't have to worry about reflecting 1/2 the light, and all of the losses which come with that. They seem to be about 50% more efficient, as far as growth per watt. And, the plants just look healthier and more natural under them, compared to fluorescents.
Famousmockingbird,
About the spectrum, plants do use blue most, but as far as white LED's go, they ALL have a ton of blue. The LED is a blue LED, and then the phosphor coating adds the rest of the spectrum. So that's why for a single emitter, the reddest possible white emitters work the best. (I think mine are 2700k) The cool white simply don't have enough red. Obviously red LED's would be more efficient than the thick phosphor coating the warm white led's use.
Still, for these relatively inefficient LED's, they're way better than CF's and halides.
They were also easy 🙂. Mount one big emitter to an old CPU heatsink, and project complete.
Since there are a lot of engineers here, I'll also mention.. You might notice if you start looking at datasheets, the bridgelux emitters I used have efficiency numbers that are about the same as metal halides, which isn't great. (they might be better by now.. Mine are about 4 years old) But, they work much better due to all the light being emitted in one direction. You do still need a reflector to catch the light at the edges, but it's nothing compared to traditional lighting.
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What I am looking for in addition to the wavelengths is the power ratio of the three sources of light.
There is little point in shoving out more power than needed at one wavelength while not putting enough out at another wavelength.
That is why I was thinking of using digital photography in order to work out what the leaves absorb at different stages of growth.
There is little point in shoving out more power than needed at one wavelength while not putting enough out at another wavelength.
That is why I was thinking of using digital photography in order to work out what the leaves absorb at different stages of growth.
In my own experience to not waste power on certain wavelengths I only use blue light around 450nm for all the early green growth. When plants mature and it's time to flower or fruit that's when I add the red 650nm spectrum in.
I'd throw in a small percentage of red w/ the blue light, and blue w/ the red, to see if the plants were any happier. I need to get some LED's and build a couple red/blue fixtures before fall, to do some experiments.
I've read different plants have different reactions to the red or blue light, too. People on the hot pepper forum say peppers get bushier under red, and tall under blue. That makes things more difficult for a traditional gardener, w/out a monoculture.
I've read different plants have different reactions to the red or blue light, too. People on the hot pepper forum say peppers get bushier under red, and tall under blue. That makes things more difficult for a traditional gardener, w/out a monoculture.
Don't ignore some of Cree's offerings. They have released high CRI (93+) LED arrays that go down to 2700k and emit far more red than their previous products did. I've used lots of these in standard domestic lighting and the light they put out is indeed a step above standard 80CRI warm white LEDs of the same CCT.
If they like red, these may be more suitable for some plants.
Then there's the MCE and XML packages that also come in colour variants that include a red, green, blue and white emitter all inside one package. Obviously you'd need a more complex driver for them, but once designed you'd get to vary the light spectrum in whatever way you desired when using them.
If they like red, these may be more suitable for some plants.
Then there's the MCE and XML packages that also come in colour variants that include a red, green, blue and white emitter all inside one package. Obviously you'd need a more complex driver for them, but once designed you'd get to vary the light spectrum in whatever way you desired when using them.
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