What should be the ideal night temperature for rose cultivation?

Correct option is B

For successful rose (Rosa spp.) cultivation, maintaining the right temperature — especially night temperature — is crucial for flower quality, size, color intensity, and plant health.
Key Points:
· The ideal night temperature for rose cultivation is around 15.5°C.
· Why 15.5°C?
· At this temperature, optimal respiration and nutrient mobilization occur in rose plants.
· It promotes:
· Large-sized blooms.
· Rich color development.
· Strong stem growth.
· Too low night temperatures can slow growth, while too high night temperatures can lead to poor-quality flowers and faster plant exhaustion.
· Day temperature ideal for rose cultivation generally ranges between 25–30°C.
Other Options Explained:
· (a) 10°C:
· Too low; can slow down plant metabolism and lead to poor flower development.
· (c) 22.5°C:
· Too warm for night conditions; can cause stretchy, weak stems.
· (d) 26.5°C:
· Very high for night temperature; poor quality flowers and rapid respiration loss.