Clear differences in vase life can occur between roses from different nurseries, when the same variety is cut at the same day. To discover the causes, production parameters were monitored on the variety 'First Red' grown on 35 different Nurseries. After two 6 weeks periods of monitoring, stems were harvested and pre-harvest and post-harvest factors were analysed. For vase life the mean relative humidity in the greenhouse was the most important variable to explain the differences in length of vase life. The number of small shoots per square meter, present in the crop at the moment of cutting, also influenced the vase life. For bud opening it was not surprising to see that the ripeness of the flower bud was the main factor influencing flower development. Also a growth temperature below 19°C was beneficial to bud opening. Further analysis indicated which part of the differences in vase life and bud opening could be explained by the measured variables. N. Marissen, J. Benninga ISHS Acta Horticulturae 543: VII International Symposium on Postharvest Physiology of Ornamental Plants www.actahort.org