Bloemtak-uitloop Phalaenopsis: effect van temperatuur, lichtspectrum en daglengte

Abstract

Growing Phalaenopsis is energy-intensive due to the need of lighting in winter, a warm vegetative phase (29°C) and cooling for fl ower induction (± 8 weeks 19°C) in summer. Commissioned by Kas als Energiebron, the cooperation of pot orchid growers and supported by Philips and Hermadix, Wageningen UR Greenhouse Horticulture and Plant Lighting investigated practical strategies for energy saving on cooling and lighting. Depending on the variety, it is possible to cool less (22°C) in the fi rst 2 to 3 weeks of the fl ower induction phase without negative effects on the number of spikes and fl ower buds. For the fastest cultivar tested however, 2 weeks of 22°C was too long, which makes practical applicability diffi cult. Additional lighting in summer with a low intensity of red light in the evening or during the day had no positive effects. There were no differences in plant quality when plants were illuminated with red/blue LED-light or SON-T (4 mol/m2/day supplemental lamp light) during fl ower induction when plant temperature was kept equal. So lighting with LEDs can save electricity for lighting, but also for cooling in periods with supplemental lighting and relative warm outside air temperatures (autumn/spring). Shortening of day length from 15 to 12 hours during the fl ower induction phase (cooling) in summer had no positive effects on the number of spikes when crop temperatures were kept equal.