Work carried out by lighting supplier Signify at its Philips GrowWise Research Centre has shown how vertical farming techniques including hydroponics, artificial lighting and precise climate control can optimise year-round raspberry production.
The Philips trial began with chilled primocane-fruiting young plants for the initial harvest flush. Compared to outdoor cultivation, by growing indoors the company says it could maintain a higher planting density thanks to the precise regulation of climate, lighting, and irrigation, and by deeper light penetration into the crop canopy.
The trial used a primocane raspberry variety that required little chilling for flower induction, with the aim of assessing yield during the primocane flush and investigating the potential of producing subsequent primocane flushes without undergoing cold storage-induced dormancy in between.
Philips says that raspberry cultivation in a fully controlled environment would allow for year-round production, enabling an uninterrupted yield. In contrast to the conventional cycle of one primocane and one floricane flush per year, vertical farming systems therefore could offer the potential to exceed two harvest cycles within one year, making production much more efficient and potentially bring higher yield on a yearly basis.
The initial primocane flush of the trial yielded comparable results to outdoor cultivation on a per-plant basis. But due to the higher planting density indoors and shorter growth cycle from young plant to harvest completion, the berry yield effectively matched a full year’s outdoor primocane + floricane cultivation per square meter. Achieving approximately 2.5 kg/m2 in the 18-week first primocane period, which is equivalent to nearly 140 grams/m2/week.
According to Philips, the results show that repeated primocane cycles with fresh young plants could eventually yield approximately three times the outdoor full-year production per square meter, although following the floricane harvest, the canes will no longer bear fruit and should be replaced with new starting material.