High output LED in hybrid lighting for Alstroemeria

Alstroemeria cultivation in the Netherlands requires artificial light in order to overcome the low levels of natural light in winter. Typical supplementary light levels are low (60-100 µmol m^-2 s^-1). In order to increase the supplementary light intensity with the lowest possible electricity costs, Alstroemeria producers are placing LED lights as an addition to the existing High Pressure Sodium lamps. This paper describes an experiment at a commercial nursery with a Hybrid lighting installation. The Hybrid lighting was created by complementing the existing 61 μmol m^-2 s^-1 HPS lamps with 21 μmol m^-2 s^-1 Philips High Output (HO) LED lamps to a total intensity of 81 μmol m^-2 s^-1. The performance of the crop under this hybrid lighting was compared with that under the existing HPS installation (62 μmol m^-2 s^-1) and with that under Regular Output (RO) full LED at an intensity of 79 μmol m^-2 s^-1 . The experiment lasted 16 months. The total light sum over de duration of the experiment in the Hybrid lighting was 4% higher than in the HPS reference due to the higher intensity installed and the fact that the grower switched on the HO LED lamps for more hours than the HPS lamps. The light sum in the LED treatment was 3% higher than the reference, due to the higher intensity, as it was used as many hours as the HPS lamps. Both the Hybrid and the LED lighting systems increased production. Of the three systems, the LED option was the most energy-efficient.