The 2022-2023 growing season will build on the results from the previous cultivation study, 'Tomato fossil-free with LED.' This is what Stijn Jochems of Delphy shares on 'Kas als Energiebron.'
One of the objectives this year is to use the most efficient lighting strategy possible for both the wallet and the crop, not only by dimming the intensity of electricity prices and irradiance but also by adjusting lighting times and lighting during cheaper hours.
Indeed, unlike previous studies, an exposure period of 22:00 to 16:00, an earlier start in winter (now that the days are getting longer again, the strategy has been adjusted to 18 hours before sunset). This increases exposure in the relatively cheaper night hours at the expense of the hours in the late afternoon, which tend to be more expensive. As a result, most pollination must take place in the exposed night. This is because the moment the sun begins to shine, the flowers already start to close. So the period when the bumblebees can pollinate under sunlight - where the flowers are open - is short with this strategy of exposure.
Bumblebees more active
It was clear from last year's study that the spectrum had a major impact on the activity of the bumblebees. Indeed, under the 'daylight' spectrum (a high ratio of blue and green light), the bumblebees were much more active. Thus, the hypothesis put forward is that sufficient flying is possible at night with the lights on, provided the right spectrum is used. The current trial compares two spectra. A wider spectrum (a higher proportion of blue and green light, 3.25µmol/J), and a standard 90R;5B;5G spectrum (3.5µmol/J).