Takes light frost
Calendulas bloom best in cool weather, so plant in early spring. Sow seeds 1 inch apart in well-drained soil in full sun. Cover 1/2 inch deep, firm soil and keep seed bed moist. Germination takes 1 to 2 weeks. After seedlings are well established, thin or transplant 8 inches apart to allow for good air circulation and discourage mildew. Calendulas can be sown again in midsummer for fall bloom.
In early spring, sow seeds 1 inch apart in a container of seed starting mix and cover 1/2 inch deep. Keep evenly moist as seedlings emerge and provide a good light source until ready to plant outdoors. Transplant when seedlings are about 2 to 3 inches tall after gradually acclimating plants to outdoor conditions. Thin or transplant seedlings 8 inches apart for best performance.
Plant when weather is cool to get sturdy plants that bloom for many weeks if faded flowers are removed. Grow this quick-flowering, easy annual along with snapdragons, cornflowers and pansies for late spring bloom. In mild climates, sow again in late summer for winter or very early spring flowers.