In late year , interest in LED ignition among chrysanthemum cultivator has increased considerably . ab initio , they were interested in hybrid lighting systems , where light-emitting diode postscript the exist HPS light , but now they are also interested in full LED . In the choice of the LED lighting system , cultivator have questions about the lighting spectrum , especially on the controller of elongation and response metre . Growers fear that chrysanthemums may remain too light in winter . That is why , when using full - LED , the options to control stem duration with the luminance spectrum are enquire .
In the autumn of 2021 , the business unit of measurement Greenhouse Horticulture of Wageningen University & Research investigate the effects of the luminosity spectrum on the increase and development of four chrysanthemum varieties . solvent showed that stem length can be provoke very well by “ end - of - day ” lighting with 20 μmol / m²/s far - red light for 30 minute . what is more , days to flowering were reduced , as well as ( undesirable ) blast growth in the low part of the canopy . The query remain whether comparable personal effects can be achieved with lower intensity or a light geological period of far - ruddy brightness . That would be a good steering mechanics to control stem duration to the hope value . Another question is whether the far - red light at the end of the twenty-four hour period is necessary during the intact refinement period , or whether applications programme during the first period of cultivation is sufficient .
To answer these interrogative sentence , Wageningen started the polish of four chrysanthemum varieties under 200 μmol / m²/s full light-emitting diode in May 2022 . wintertime conditions were imitate in IDC LED , with glasshouse cooling and maintaining a share of sunlight of approximately 20 % and of lead brightness level of 80 % . Intensities of far red luminosity at the close of the twenty-four hour period change between 20 , 10 and 5 mol / m²/s , and the continuance ranged between 10 , 20 and 30 minute . In addition , the per centum of green and far - crimson Light Within in the spectrum during the day , and plants were also mature at a lower light strength ( 100 mol / m²/s ) .
Chic plant were harvest from hebdomad 28 forwards . Flowering halt of Magnum , Pina colada and Baltica will be shortly . The first termination show that plants grown under the " end - of - day " far - red treatment can be harvested a few days earlier than without “ end - of - day ” far - flushed light . give “ end - of - day ” far - red light only during the first hebdomad of polish does not give the same upshot as when the end - of - day discussion is give during the entire cultivation . In the coming weeks , prime of all treatments will be glean , and the upshot for stem length , weight , and light habit efficiency will be collected and analyzed .
This research is fund by the Ministry of Agriculture , Nature and Food Quality and Glastuinbouw Nederland within the plan Greenhouse as a source of vigour , with a contribution to the lamp and their control by Signify .
For more information : WURwww.wur.nl
