|Authors: ||T. Van Delm, P. Melis, K. Stoffels, R. Vanderbruggen, W. Baets|
|Keywords: ||Fragaria × ananassa, HPS lamps, LED lamps, artificial light, wavelengths, light intensity, lighting strategy, forcing, earliness|
Over the years, the strawberry season in Belgium developed to an almost year-round production from mid-March until early January.
This became possible by combination of cultivation systems and the cold storage of plants.
With assimilation light, the season could even be more extended.
To test the possibilities of advancing the strawberry season by lighting in combination with an increased temperature in the glasshouse, trials under high pressure sodium (HPS) lamps were started in 2006 and continued till 2010 with different cultivars.
A lighted and unlighted glasshouse, both 250 m2, were compared under 130 µmol s-1 m-2 supplemental lighting.
From 2012 to 2014 trials with LED were done with December plantings of strawberry cultivar 'Clery'. With LED assimilation light, different light intensities (35 and 70 µmol s-1 m-2) were compared in combination with light strategies, and different LED systems were compared with two spectra.
This study shows an increase in petiole length and leaf area under assimilation lighting.
The assimilation light caused an earlier yield, but the advancement was reduced when less artificial light was given.
The total yield decreased with lower light intensities or reduced operation hours.
Next to that, an increase in total yield could be obtained, but was negatively correlated with earliness.
The regulation of temperature and lighting strategy seems to be important for plant balance between earliness and total yield.
The strawberry season is advanced with assimilation light until beginning of February.
The final gap can be filled by plantings in October to produce strawberries in January-February, to obtain a year-round strawberry production in Belgium.
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