Sustainable horticultural is a challenging task since the world-wide increase in population, accompanied by increasing food demand, and the current consensus is that we must move towards more sustainable practices. This challenge leads to a need for higher production yield in agriculture that in turn rises energy demand of the agricultural industry. Therefore, greenhouse cultivation became the main supplier of fresh vegetable worldwide. Light is the most important source of energy for plant photosynthesis and a vital signal for plant growth and development. However, plant response to light varied with light quantity and quality. Conventionally, high-pressure sodium (HPS) lamps are used in commercial greenhouses as a supplemental lighting source above plants.
