Since horticultural LED technology evolves rapidly and becomes more and more economical, an increasing number of growth facilities are installing LED grow light as replacement for conventional HPS lamps. The large choice in LED systems and the option to dim individual channels in a multi- channel system results in an immense variety of different spectra to be used. This challenges the comparability of observations in plants grown in different LED indoor facilities, especially since a universally agreed-on standard spectrum for LED plant growth chambers is missing. In a new project that will be jointly led by plant physiologists at the University of Basel in Switzerland and LED experts at Heliospectra in Göteborg, Sweden, we aim to develop optimized setups for different LED systems to enable near-natural plant growth and a better comparability among different LED-based growth chambers.