Efficient lighting system for greenhouses

The proper plant growth is dependent on the right balance of light wavelengths. In restrictive conditions for a greenhouse construction (e.g. in urban areas, in the proximity of supermarkets or groceries), the absence of sunlight can be successfully compensated by a system of artificial lighting. There are available on the market different grow lamps (fluorescent, metal halide, high-pressure sodium, led) that provide blue light for foliage growth and red light for flowering and fruiting, but these are dimensioned only qualitatively and not quantitatively concerning the photosynthetic active radiation. Based on the LED Spectra dedicated software, the paper presents an analysis regarding a standard LED grow lighting module for two species of plants. The results will be assessed by factors related to the absolute number of photons, as the grow light system is adjusted in accordance to its capacity to stimulate photosynthesis of a certain plant. Finally, LEDs were compared with fluorescent and metal halide lamps regarding grow lighting efficiency for a certain crop.