USING FLOWERING AND HEAT-LOSS MODELS FOR IMPROVING GREENHOUSE ENERGY-USE EFFICIENCY IN ANNUAL BEDDING PLANT PRODUCTION
In temperate climates, annual bedding plant crops are typically produced in heated greenhouses from late winter through early summer. Temperature, photoperiod, light intensity, and transplant date are commonly manipulated during commercial production so that plants are in flower for predetermined market dates. We used nine flowering models that predict the effect of mean daily temperature on time from transplant until first flowering, which can be used to identify the combinations of transplant dates and growing temperatures necessary for flowering to occur on chosen market dates. The computer program Virtual Grower was also used to estimate greenhouse heating costs based on user-defined inputs such as building material, construction style, temperature set point, heating system, and typical weather at the selected locations. Using the flowering models and Virtual Grower, the temperatures and transplant dates that consumed the least amount of energy for heating, on a per-crop basis, were estimated for two market dates and three U.S. locations. For flowering on March 15, the estimated energy consumption for heating per crop decreased in Michigan as the greenhouse setpoint increased from 15 to 24°C for all species. In contrast, the temperature that elicited the lowest heating cost per crop in North Carolina for a March 15 finish date varied among species. This kind of analysis allows the determination of the most energy-efficient production schedule for greenhouse- and crop-specific situations.
Runkle, E.S., Blanchard, M.G. and Frantz, J.M. (2012). USING FLOWERING AND HEAT-LOSS MODELS FOR IMPROVING GREENHOUSE ENERGY-USE EFFICIENCY IN ANNUAL BEDDING PLANT PRODUCTION. Acta Hortic. 957, 99-106
floriculture, temperature, virtual grower