Manipulation of Light Frequency by LEDs and Phalaenopsis Orchid Spike Growth

Phalaenopsis orchids are currently the most popular potted plants in the United States.  Production of these plants takes several years and requires an investment in order to efficiently produce these plants.  As lighting sources transition to more efficient LED arrays, characterizing production potentials and optimal light conditions could allow for more aesthetically pleasing plants in a shorter time.  Due to the different stages of production, LED lights are possible for use in both greenhouse as well as indoor controlled environment chambers.  Thirty-nine Green Pixie  FR 509 Phalaenopsis orchids were grown under Lumigrow LED bars consisting of varying percentages of red and blue light.  Light intensity was 200 μmol m^-2 s^-1 in each treatment with temperatures constant between 22–23 °C.  Treatments consisted of 0%, 10%, 20%, and 40% blue light in μmol·m^-2·s^-1. The amount of blue light resulted in different amounts of flowers on the inflorescence spike.  In the treatment containing no blue light, plants appeared lighter in color and flowers opened in the longest amount of time.  Overall spike length showed differences between treatments as well.  The production time to first flowers differed significantly between treatments suggesting an optimal percentage of blue light around 10%.  These differences were likely due to specific hormone and pigment production as a result of the blue light.