Production and Management Measures for Cut Rose in Different Seasons

(1) Winter: mainly sunny days, strong light, and a large temperature difference between day and night. A short period of extreme low temperature occurs at the end of December. In southern Jiangxi, the large temperature difference between day and night is very beneficial to the accumulation of dry matter in cut roses, and the cut roses have large heads, many petals, and bright colors. However, in winter the day-night temperature difference inside the greenhouse often reaches above 20°C, and an excessively large day-night temperature difference can cause the petal edges of many cut rose varieties to turn black and the flowers to become deformed. The minimum night temperature required for cut rose growth is above 8°C; too low a night temperature is unfavorable to cut rose growth, mainly affecting sprouting and branching, resulting in low yield. From mid-December to the Spring Festival each year, extreme low temperatures occur in some areas of central and northern Jiangxi, with the lowest temperature reaching -5 to -1°C, and simple greenhouses with poor insulation performance are prone to freezing damage.

(2) Spring and summer: From spring to early summer, it is mainly sunny, with strong light, high temperature, a large day-night temperature difference, and strong winds. It is very necessary to use natural ventilation for cooling and to add certain ventilation and cooling facilities so that the roses can get through the short periods of high temperature. The high-humidity climate of late spring and early summer (air relative humidity above 70%) has little effect on roses, which need a certain amount of humidity to grow well. Too low humidity affects the flower color of cut roses and can even cause the outer petals of the flowers to scorch, seriously affecting the quality of cut roses. Installing certain equipment to regulate ground humidity and air humidity is the best solution. Practice has proved that treating roses by increasing humidity in relatively dry seasons can significantly improve cut flower quality. During the plum rain period, high temperature, abundant rain, and insufficient light bring continuous rainy weather that lasts for a relatively long time, which is unfavorable to rose growth; high temperature, high humidity, and low light often cause outbreaks of diseases and insect pests. Therefore, facilities for enhancing ventilation and dehumidification and for preventing and controlling diseases and insect pests are needed.

(3) Autumn: In autumn, the temperature gradually turns cool, rainfall decreases, light is sufficient, and pest and disease damage is relatively light. The climate and environment are relatively suitable for cut rose growth, and the plants grow relatively fast. Attention should be paid to maintaining a balanced supply of water and fertilizer to ensure high yield and high quality of cut roses; for plants that have passed the peak cutting period, bend and prune the branches, and apply more organic fertilizer to promote rapid plant growth and prepare for winter cut flowers. After late autumn, the temperature turns cold, and because of the low nighttime temperature inside the greenhouse, the humidity increases, which easily induces gray mold and downy mildew. Attention should be paid to nighttime insulation measures and to controlling the nighttime humidity inside the greenhouse.