Heat Delay - Garden Mums
Thursday, 02 September 2010 11:41
High night temperatures can cause mum flowering to be delayed.
Chrysanthemums are short-day plants. Both flower initiation and development of the flower buds occur more rapidly under short days than under long days. However, temperature has a greater influence than daylength on flowering of garden mums.
Delay of flowering and in more extreme cases, failure of buds to develop properly (crown buds) are often associated with heat delay. Heat delay occurs when night temperatures are greater than 73F. Garden mum cultivars vary in their sensitivity to heat delay. Also research at Kansas State University has shown that plants are more sensitive to heat delay when plants are subjected to high night temperatures during the first 2 weeks of short days, during flower bud initiation. Plants subjected to high night temperatures after 3 weeks of short days showed no permanent damage and only exhibited delayed flowering.
Dr. Kimberly Williams, Kansas State University explains heat delay in this short video.
Tina Smith, UMass Extension and Leanne Pundt, UConn Cooperative Extension
