Fittings with special requirements for plants: Red (~660mnm) & blue (~450 nm) are the most appropriate wavelengths from a technical point of view – Chlorophyll absorption has maxima at 400- 500 and 600-700 nm Different wavelengths stimulate different plant properties: Blue stimulates flowers to open up („wake-up call“) Red/deep red stimulates growth and flowering (direct absorption in Chlorophyll) IR can trigger growth of long-night plants („prolonged sunset“)