Eric and Lander van den Eynde’s company close to Antwerp consists of 2 ha of unlit tomatoes and 2,1 ha of lit, high-wire cucumbers. “We have been growing under HPS lights for two years already, which complemented the natural light with 180 µmol/m²/s”, says Eric. “However, in winter the fruits did not reach the desired weight of 350 to 400 grams. Therefore, light had to be added and LED is the most efficient solution for that. Our question to Signify was how we could fulfill that in the smartest way.” Multiple light plans were calculated in consultation with their installer and the plant specialists from Signify. Because of the limited height of the greenhouse (gutter height 5 meters), the Philips GreenPower LED toplighting linear was chosen, because that gives the most uniform light distribution.
Half of the HPS lamps were removed, and for each removed lamp 2,9 linear LED modules were installed. This brought the total light intensity to 223 µmol/m²/s, divided between 87µmol/m²/s HPS and 136 µmol/m²/s LED in red, blue and a bit of white working light. The total installation gives 24% more PAR-light, while the energy usage (at equal lighting hours) is about 7% less.
“The light division is nice and equal, even when only the LED lights are on”, the grower continues. “The latter is the case every now and then in the Spring and Autumn especially, when the heat radiation from the HPS lights is not always wanted.”