Fall is the Best Time to Grow Cosmos in Warm Climates
01.10.2024 - 17:01
/ balconygardenweb.com
/ Ralph Astley
Isn’t fall when all garden things shed, and plants push out the final blooms before diving into dormancy? Not if you live in a warm climate—which makes autumn perfect for growing the spectacular, summer-blooming cosmos! Let’s explore.
Cosmos flowers are usually planted in early spring after the last frost date has passed and then from mid-summer well into fall. They prefer hot, dry conditions, can tolerate poor soil, and need 6-8 hours of sunlight daily for the best blooms!
But this doesn’t mean you can’t plant it in the fall! If you live in a moderate or frost-free zone where the temperatures remain above freezing most of the time, your cosmos will flourish and give you beautiful flowers.
Early to mid-fall is ripe to sow cosmos seeds in the ground for those inzones 8-9 after checking the local frost dates. Cosmos are half-hardy annuals that may tolerate chilly weather, but they will die back with frost.
Germinate the seeds indoors and then transplant them outside to a sunny spot in the garden or in pots. In frost-freezones like 9-11, you can sow seeds directly in the ground in autumn, as long as the soil is well-draining.
Pro tip: Mulch the soil in late fall and early winter and provide frost blankets to insulate your cosmos from extreme cold!
The ideal temperature range for planting cosmos and getting them to bloom is 60-80 F (15-26 C). You would risk slower or even no germination if you planted cosmos during late spring or summer in warmer regions that exceed 80 F! Here are some tricks to help you.
The conditions in zones 10-11 are better suited for fall and winter planting, as the lowest temperatures mostly remain above 30-40 F.
Cosmos germinate anywhere within 7-14 days and start blooming quickly within three months of