Dayan, E., Agricultural Research Organization, Gilat Experimental Station, Hanegev 2, 85280, Israel
Presnov, E., Agricultural Research Organization, Gilat Experimental Station, Hanegev 2, 85280, Israel

A case study in Israel involved adjustment of cooling and training methods to improve the quality of greenhouse rose flowers, as flower quality is poor under the hot temperatures that prevail during summer. Experimental work with common cooling methods failed to show any conclusive quality improvement or economic benefit. To improve flower quality, growers needed a better understanding of the biological and physical processes involved that influence flower quality. Physical and growth models were merged to highlight situations in which the grower could adjust either his crop training methods or the application of cooling systems to meet changes within the architecture of the rose canopy and within the ambient environment. Analyzing data from these models provided explanations for the daily, seasonal, age-dependent and agro-technical effects on the instantaneous energy balance within the rose canopy. These explanations help farmers understand the causes and timing of the mutable energy situation within the greenhouse and suggested modifications for a better use of their facilities. Farmers who joined this study vastly improved flower quality and saved both energy and water by undercutting to maintain a green crop during the hot season and by applying wet pad systems and intensive ventilation when the rose canopy could not cool itself. © ISHS 2005.