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LSG PAR38-style grow light sale

Discussion in 'Everything Else Orchid' started by naoki, Nov 30, 2015.

  1. Nov 30, 2015 #1
    naoki

    naoki Well-Known Member

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    I noticed this Black Friday deal (until Mon).

    https://www.lsgc.com/products/black-friday-cyber-monday?variant=8978702661

    $99 for 4x 13W bulbs (normally around $160).

    Here is the spec:
    https://static.lsgc.com/downloads/dl/file/id/42/mynature_grow_broad_spectrum_specification_sheet.pdf

    PPF of 21.70 micomol/s from 13 W, which is 1.67micomol/J efficiency. Some of you may not know how to interpret the specification, but this is pretty much at the top efficiency of the LED and HPS grow light according to this independent test. Light Science Group (LSG) and the BML delivered the top level efficiency in this test. The test was with a bigger model.

    The beam angle is 40 degree, so you can place it far away from the plants. At 24", it delivers 150 micromol/m^2/s, which is at the Cattleya level light (or slightly lower than that), and covers about 16" diameter.

    Even with the sale price, it is fairly expensive, but it is a very efficient one (so you can save money in a long time (a couple years)). With DIY COB, we can get a higher efficiency for less money. So I personally wouldn't buy it, but some people may be interested in this kind of screw-in bulbs. There are lots of crappy PAR38 style LED lights, which are not worth getting, but you shouldn't confuse this LSG bulb with the cheap ones.
     
  2. Nov 30, 2015 #2
    Ray

    Ray Orchid Iconoclast Supporting Member

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    Are you getting a kickback from them, Naoki?

    Just kidding, but that spectrum does not look particularly good to me. Am I missing something?
     
  3. Nov 30, 2015 #3
    naoki

    naoki Well-Known Member

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    I wish, but no. :)

    It is a typical R,B,W style grow light, isn't it? When you are looking at the spectrum, this one is gives in the absolute PPF (micro mol/s), which is more useful than the typical relative spectral power distribution (SPD) curve (watt on y-axis). So the blue peak would be much bigger than this if you covert it to SPD.

    If you are saying that it doesn't look because the plants would look black, you are right.

    Photosynthetically, it would be pretty efficient. With orchids, I haven't found a convincing evidence that R+B doesn't work. Or I should say that there doesn't appear to be lots of research about photomorphogenesis in orchids. Have you? I'm using mostly white COB now, and have only one R+B LED left for orchids. Mine is old (not so efficient at the current standard), but orchids under it (Catt. and some multifloral Paphs) seems to grow and flower normally. I have a feeling that they may become deeper green, but it may be just from a placebo effect.

    Did you stop carrying Philips GreenPower? I think they had similarly efficient PAR-38 type (but with white+R), right?
     
  4. Dec 1, 2015 #4
    Ray

    Ray Orchid Iconoclast Supporting Member

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    Would they look black under them? I don't think so. The black appearance comes from the use of lighting with no green in the spectrum.

    My comment was related to the fact that the spectrum showed a large blue peak and little in the red. I'd like to know how that spectrum relates to the plant absorption spectrum...

    If I could get the Philips lamps from my distributor, I would still have them available... They were the far-red "flowering lamps", with white added. The white was done for the sake of workers, not for the plants, although it does provide plenty of blue light in its spectrum. Red-blue is just more efficient.

    I just got a sample of a 40-watt PAR 38 lamp from the factory that makes my other lamps (they're back in stock, by the way), and it is very interesting. Each one has its own cooling fan, and man!, is it bright. I'm still waiting on some test measurements.
     
  5. Dec 1, 2015 #5
    naoki

    naoki Well-Known Member

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    The emission spectrum in the spec shows that most of the light is from 660nm region, which is considered to be the peak in photosynthetic efficiency, and about 12% blue (around 430nm). This is pretty standard RB composition; red for photosynthesis efficiency and a little bit of blue for crypto chrome.

    PAR38 with active cooling is interesting. Does it have the heat protection for the case of fan failure? It's not using synthetic jet (SynJet) cooling, which are supposed to be more robust, instead of normal DC fan, does it? See Fig. 6 of this page.
     
  6. Dec 2, 2015 #6
    Ray

    Ray Orchid Iconoclast Supporting Member

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    My question about the spectrum is based upon the fact that every graph of plant absorption I've seen shows red and blue peaks to be roughly equal, yet white LEDs all are very high in blue, with relatively little red.

    According to the manufacturer of the test lamp, the passive cooling is sufficient for the lamp, but the fan (not a synjet) is intended to extend the life.