Calendula (also called pot-marigold) prefers cool weather. In hot summer areas like Arizona, calendula grows best throughout the cooler months of late fall and spring. 

Plant calendula after the last spring frost in cold weather climates. 

In the low desert of Arizona, plant calendula seeds and transplants beginning in late September through November. Calendula blooms in Arizona from December through May. 

Succession plant calendula every 2 or 3 weeks for a continual harvest.