Sustainable gerbera production realised with the next generation greenhouse cultivation

In spite of a considerable decrease during the last decade, energy consumption in greenhouse cultivation remains high. More sustainable greenhouse horticulture can be realised by developing new greenhouse and cultivation concepts. Recently, we developed the Next Generation Greenhouse Cultivation system, with which energy consumption in tomato can be reduced by 40% while maintaining production and quality. This concept is based on the use of thermal screens combined with control of a high humidity level, maximizing the integration capacity of the crop, improved CO2 efficiency by reducing ventilation, and greenhouse cooling combined with a heat pump and aquifer. We adapted this concept for Gerbera cultivation and tested it in three consecutive years of experimentation. This resulted in a reduction of energy consumption by 42-50% compared to that of commercial growers, while maintaining production levels. Energy reduction was realised by using thermal screens combined with forced ventilation and an adaptation of the lighting strategy. By using forced ventilation, the use of a fixed minimum pipe temperature can be abandoned, which is normally used to control humidity. In order to prevent low root temperatures, local heating was applied beneath the pots. The use of assimilation lighting was optimised based on the daily light integral required for the growth of Gerbera. This resulted in reducing the amount of assimilation lighting. By shortening the day length to 10.5 hours from October until January the number of flowers increased, albeit with a lower fresh weight. Recommendations for practical application for the use of screens, forced ventilation and optimal lighting strategies are given.