In 2011 researchers from Wageningen University and Research Center (Herman van der Wekken and Frank van der Helm) performed research with Philips LEDs into the use of a small amount of red, far-red and/or blue light in order to influence flowering. The aim was to control quality and growth rate in the summer and in the winter for a variety of cultivars. The results looked promising in the research environment: it was possible to delay flowering by adding red light. This would mean that higher-quality branches could be obtained in summer, and it was evident that earlier flowering could be achieved with far-red light. These findings were reinforced by positive practical experiences with the Philips GreenPower LED flowering lamp in Lisianthus cultivation that was otherwise unlit. Production has been going on for a year with low LED lighting levels, resulting in heavier branches and more blooms.
The principle has still to be proved in practice for growers with an existing high-pressure sodium lighting installation. The financial picture also needs to tally. Philips has therefore decided to get together with Miracle Flowers and installer GST of ’s-Gravenzande to conduct a trial in which Wageningen University and Research Center’s results can be further confirmed and optimized in a practical situation. GST has built an installation involving two different types of Philips GreenPower LED flowering lamps, which have been burning since December alongside the new assimilation lighting (210 micromoles/m2/s). In conjunction with Philips, a lighting strategy has been selected for the initial cultivation round in which the emphasis is on the use of far-red light for the purpose of speeding up the slower cultivars. In the first trial round the results were very encouraging: the branches that had received most far-red light were 3-4 days earlier, heavier, longer and had a few more flowers. The trial is to be monitored for a year so that the effects can be ascertained in different seasons. In this way a light recipe can be developed that will improve Lisianthus cultivation.
For more information:Philips Horticultural Lighting
Esther Hogeveen- van Echtelt, Horticulture Application Specialist
The Netherlands
T: +31 (0)6 233 42 932
E: [email protected]
www.philips.com/horti