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LED full spectrum grow lights.

Discussion in 'Orchid Culture' started by Mark in NY, Mar 28, 2019.

  1. Mark in NY

    Mark in NY New Member

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    Hi! I'm using full-spectrum LED grow lights in my basement orchid setup. My phalies LOVE the environment and are growing and blooming like mad, but my Cattleyas, although lots of growth, aren't doing too well in flowering. Those that bloom are MONTHS later than normal (I used to have a small greenhouse) and many buds are rotting in their sheaths. My light meter says about 2-4000 f.c.s which should be enough light. My first time using LEDs; do they not give enough light??? Do I need to up the RED leds for flowering?? All suggestions appreciated!

    Mark in NY
     
  2. naoki

    naoki Well-Known Member

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    Mark, welcome to the forum. Do you mean phosphore-based white LEDs by "full spectrum"? If so, it seems to be sufficient for Cattleya. I don't have lots of big Catleya, but C. walkeriana, C. nobilior, C. warnerii, C. maxima etc. flower normally under white LEDs. Most of them are under 4000K, but a couple of them are under 5000K white LEDs.

    Some Cattleya species are photoperiodic. I just looked at Joseph Arditti's book: Fundamentals of Orchid Biology. For example, C. labiata is a short day plant with day length of <16.5h induces flowering. C. trianaei is also short-day plant, <9h induces flowering under 13C and 18C, and 16h day can delay the flowering. Frequently this kind of critical values for the photoperiod is influenced by other environmental factors such as temperature.

    Other Cattleya spp. listed as possible short day plants are C. mossiae C. percivaliana, C. schroederae, C. skinneri, C. trianaei, C. warscewiczii.

    Photoperiodic plants use something called phytochrome, and actually they are measuring the length of night. So in some sensitive plants, if you disturb the night by exposure to light for a couple minutes, the phytochrome night timer gets reset, and the plant think that the night is short (so flowering might not be induced).

    Interestingly, if you shine far-red light just before it goes dark, they think that it is long night (even if the actual darkness is short). Far-red light has the effect of running the night timer faster. Here is some more concrete information: Phytochrome

    High K (bluer) LEDs have relatively small amount of FR. So it could influence photoperiodism, but I don't think it has been tested with orchids.
     
    Marni and xmpraedicta like this.
  3. Mark in NY

    Mark in NY New Member

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    Naoki - Wow! You sure know your orchids! Thanks so much for your quick response! The grow-lights are "Viparspectras" and are red, blue, white, orange, etc. Work very well! My "Catts" are all hybrids, so I'm not too concerned with species photoperiodicity. Lights are on 12 hours Winter and 14 hours warmer months. Temps run 75 degrees day, 60-65 nights. Humidity holds at 65-75 percent. My light meter shows between 2,000 and 4,000 f.c.s depending on proximity to the light banks. Can I move the Catts closer to the lights without burning them (in the case of LEDs)? Perhaps this will help? (I know HIDs can burn the plants if too close). Finally, would an extra bank of just RED LEDs encourage more and better flowering?? Await your reply ….
    Mark in NY
     
  4. naoki

    naoki Well-Known Member

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    Mark, with these blue-red based ones, the intensity measured in fc or lux is difficult to interpret. fc (and lux) measurements are the approximate intensity for human eyes, which are highly sensitive to green. So for plants, 1 fc from blue-red contains much more usable photon than 1 fc of "white"-ish light. From this, I'm guessing that you are giving quite a bit more light than what you think. So I would say that you are giving sufficient amount of light.
     
  5. Mark in NY

    Mark in NY New Member

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    Naoki - Most info on growing with "full spectra" LEDs still about pot production(!). Guess I'll have to experiment further as to distance and color type. FYI, the flowers that DO emerge under this lighting seem to be slightly larger and brighter... Thanks, again! Mark.