Issue link: https://te.mouser.com/i/1475713
mouser.com/te 29 species and even during the lifecycle of a given crop. For instance, red lettuce, Rouxai, when grown under specific LED light spectra, presents much greater yields and concentrations of anthocyanin and carotenoids [3]. Achieving optimum nutrient density/diversity and yield are major factors in creating product differentiation for indoor grown crops and can aid in penetrating new markets where traditional agriculture has naturally dominated. To realize these gains, indoor horticulture lighting needs to be flexible and adapt to a crop's lighting needs throughout its growth cycle. This isn't readily done with traditional indoor lighting solutions, such as metal halide (MH) or high-pressure sodium (HPS) High-Intensity Discharge (HID) lights. Though MH and HPS lights can be moved and filtered to change the lighting conditions, there is little outside of dimming that can adapt HID lighting to the instantaneous requirements of crops, especially if the lighting is supplemental lighting in FIGURE 1: Rouxai red lettuce is grown for 14 days under LUXEON SunPlus Lime + Purple, LUXEON SunPlus Purple + LUXEON 3535L Green, and LUXEON SunPlus Purple, Valoya, and RGB fixtures in Adaptis chambers. (Source: Lumileds) Growing populations and greater concern for the environmental impact of traditional agriculture are driving government regulation and business opportunities toward more sustainable, dense, and efficient indoor horticulture methods. LEDs are a key enabling technology for this trend and provide improved efficiency and light quality essential in optimizing indoor crop yields and nutritional value. a greenhouse. The long warmup and cooldown sequences of HID lights make this balancing act difficult. For a given crop, there is an ideal photosynthetic photon flux density (PPFD) and light spectra for each stage in its life cycle, from seedling to harvest. Ensuring the best yield and crop quality also requires considering the costs of lighting and the lighting system. Generally, the cost of the lighting is a main factor to consider, but this calculation is somewhat more complex when accounting for the needs of different crop species. It is not only the total light energy output, but the energy in the desired spectrum, or photosynthetically active radiation (PAR). Photosynthetic photon flux (PPF) efficacy measures the meaningful efficiency of a light source for a given spectrum. For these applications, LED lighting can be readily designed to provide optimal PPFD and the correct spectra to encourage specific crop features, such as greater nutrient density. Moreover, LED horticulture lighting can be created and controlled in such a way to realize much higher PPF efficacy than HIDs and in slim profiles that reduce the amount of natural sunlight blocked by lighting fixtures and infrastructure in greenhouses with supplemental LED lighting. Given the near omnidirectional light output of HIDs, bulky reflectors are needed to redirect the misdirected light from the bulbs to the grow beds. These reflectors add overall size and block natural sunlight from illuminating the grow beds. High-powered HIDs can be placed at junctions of structural members to limit the amount of natural sunlight blocked. However, this reduces the modularity and configurability of the horticulture space (Figure 1).