Technology and Materials for Passive Manipulation of the Solar Spectrum in Greenhouses

Summary

Greenhouse horticulture grows increasingly important due to its ability to provide a controlled microclimate which is optimizable for highly efficient crop growth and resource use, although it may come at a significant energy and investment cost. One of the most crucial inputs in any greenhouse is sunlight, giving free energy and light for greenhouse crop growth. However, it is enormously variable, both geographically and seasonally. This review discusses materials and technologies usable in greenhouse cover and screen materials which can passively manipulate the incident sunlight to transmit a light spectrum that is ideal for crop growth, thereby improving the yield, and for greenhouse microclimate management, thereby reducing the energy usage of greenhouses. The current status of spectrum-manipulating technology in greenhouses, developments over the last few years, some potential innovations adaptable from diverse fields to greenhouse horticulture, and the associated challenges, are discussed.