ABSTRACT Cut flowers are delicate products whose quality and longevity depends on growing and postharvest conditions. The aim of the study was to evaluate the anthochron and the postharvest of gladiolus stems produced under different growing seasons and irrigation levels. The experiments were carried out in a greenhouse in the State of Rio de Janeiro (Brazil) during the winter/spring 2018 and autumn/winter 2019 periods. A randomized block design with 5 replications was used, considering irrigation levels of 45%, 60%, 80% and 100% of the crop water requirement. Irrigation management was performed by the automatic irrigation controller, installed in the 100% irrigation level treatment. As they reached the harvest point, considered to be “showing the color” of the three basal florets, the floral stems were harvested, always in the morning, and immediately taken to the laboratory for standardization of size (75 cm). During the storage period, the stems were kept at a temperature of 25 ºC, with the base immersed in a container with 300 mL of water. Fresh mass, water absorption, anthochron and longevity evaluations were performed daily, in addition to a visual evaluation, performed using a proposed senescence scale. The occurrence of severe water deficit during cultivation interferes with the fresh mass of the stems in postharvest and increases the opening speed of the flowers. The floral stems’ longevity is reduced when gladiolus is produced under the 45% irrigation level. There are no significant differences in the longevity of flowers grown in the different seasons and the anthochron value is influenced by the water availability, being lower in the stems kept in field condition (0.70 to 0.80) in comparison to the postharvest condition (0.83 to 0.92).