S06 - Session O4 - Keynote: Opportunities and challenges with advanced greenhouse glazing materials

Authors: Eric Stallknecht, Erik Runkle *

Greenhouse glazing is critical for extending growing seasons and protecting high-value horticultural crops from adverse environmental conditions such as excessive rainfall, low temperatures, and high evapotranspiration rates. Traditionally, greenhouse glazing was made of glass, but photostable plastics such as acrylic, polyethylene, and polycarbonate are now the most widely used greenhouse glazing materials. The technological advancement of plastic tensile strength and lifespan has also facilitated the incorporation of other types of plastic additives that can increase light scattering (diffuseness), improve insulation, reduce condensation formation, and alter the transmitted photon spectrum. Each greenhouse glazing material has various combinations of these properties (i.e., different additives) that come with unique opportunities and challenges for a particular crop or location. Here, we review several of the current and futuristic greenhouse glazing technologies, focusing on their optical properties and how they can influence crop growth as well as the greenhouse environment. Among particular interest are diffuse, photoselective, spectral-shifting, and photovoltaic cladding materials. These have the potential to advance the greenhouse industry by increasing crop yield and quality and possibly even create dual-purpose structures capable of generating renewable energy. However, these materials often also have trade-offs such as higher costs and decreases in transmission of photosynthetic radiation.