Horticultural lighting system optimalization: A review

Light conditions are crucial for vegetable quality in terms of sensory properties and nutritional composition. Well planned lighting systems enable effective production and extend production season, even for year around production. Further factors, like climate change, growing urban population (urban plant factories), seasonal employment, developing consumer expectations in security, safety, freshness, and price-quality ratio of vegetables and fruits reinforce the expansion of LED systems. The main obstacle of shifting to LED lighting in plant production is that involves a complex system change beyond lighting (e.g. plant recipes, which are species- and in several cases cultivar-dependent), resulting serious associated costs. Also, lack of quality standards for solid state lighting in horticulture has been frequently mentioned. Therefore, light source measurement, parameters, metrics, and labeling was reviewed. Presented increasing number of scientific publications, patents and the increasing role of LEDs in R + D, and innovation related projects indicate that the technological background is developing fast.