BACKGROUND: Mechanization of Rosa damascena flower harvest is limited because of the asynchronous flowering period, the necessity for the harvest operation to take place in the early hour of the morning, and a lack of knowledge regarding the physical–mechanical properties of R. damascena. This study investigated the effect of harvesting hour on some physical–mechanical properties of R. damascena.

RESULTS: The terminal velocity of the rose flower ranged from 4.00 to 2.38 m s⁻¹. The highest picking force was found to be 6.29 N for the harvesting hour of 06:00 am. Tear forces of petal changed from 1.54 to 0.97 N for the harvesting hour of 06:00 am and 12:00 pm, respectively. The tension force of pedicel varied between 8.25 and 7.76 N. The weight of the rose flower was measured as an average of 1.61 and 1.50 g at 06:00 am and 12:00 pm, respectively. Horizontal and vertical projection areas of rose flowers were positively correlated with harvesting hour, with an R² of 0.97 and 0.75, respectively. Results showed that there was a minor loss in colour for both inner and outer surfaces of petals.

CONCLUSION: The results of physical–mechanical properties of R. damascena obtained from this study should be considered for the operation of flower harvest mechanization. Copyright © 2011 Society of Chemical Industry