Growth, yield, and quality in hydroponic vertical farming – Effects of Phycocyanin-rich Spirulina Extract

Vertical farming (VF) is a source of high-quality, accessible, and climate-friendly nutrition for rapidly growing urban populations. To realize VF’s potential as a food source, innovative technologies are required to ensure that VF can be industrialized on a massive scale, and extended beyond leafy greens and fruits into the production of food staples or row crops. A major obstacle to the economic sustainability of VF is the amount of lighting energy consumed and it is important to consider the implications of this energy consumption in terms of both environmental impact and profitability. While technological advances have improved the energy efficiency of VF lighting systems, there has been insufficient research into biological approaches to save energy by shortening the growth period from seeding to harvest. We conducted a controlled trial to evaluate the biostimulant (non-nutrient, biological growth improvement) potential of a phycocyanin-rich Spirulina extract (PRSE) in hydroponically grown, vertically farmed lettuce. PRSE application reduced the time from seeding to harvest by six days, increased yield by 12.5% and resulted in improved quality including color, taste, texture, nutritional flavonoid levels, and shelf life. This preliminary study demonstrates that natural biostimulants such as PRSE may play an important role in improving the economic sustainability of the nascent, but rapidly growing VF sector.