The roses usually need 3 months from planting to harvest. It’s important to plan your flowering times according to market conditions in order to periodically harvest. For this, in addition to planting, deadheading and other factors should be considered.
While this usually is 5-6 weeks in spring and summer, the duration for winter is up to 8 weeks. Also, the soft-deadheaded plants grow 3-7 days after the hard-deadheaded ones.The temperature in the greenhouse should be considered. Another factor is the size of the stems. The longer stemmed roses need more time to mature. In addition to this, altering the night temperature by 4-5 degrees ( no more than 1 degrees each night ) can hasten or slow the process.