Growing Cosmos in Zone 7b
Zone 7b has mild winters and a long growing season — good conditions for Cosmos. Last frost: Apr 10. First frost: Nov 7.
Planting Calendar
Season: Apr 10 – Nov 7 (211 days)
When to Plant Cosmos in Zone 7b
Start Seeds Indoors: Mar 13
Start Cosmos seeds indoors around Mar 13 (4 weeks before last frost). Optimal germination temperature: 75°F. Germinates in 5–10 days.
Transplant Outdoors: Apr 17
Transplant Cosmos seedlings outdoors after Apr 17. Wait until soil temperature reaches 60°F. Space plants at 12/sqft. Harden off plants for a week before moving outside.
Harvest: Jun 11
First harvest approximately Jun 11 (~55 days from transplant). Continue harvesting until first frost (Nov 7).
Cosmos in Other Zones
1a 1b 2a 2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b 10a 10b 11a 11b 12a 12b 13a 13bFrequently Asked Questions
When should I plant Cosmos in Zone 7b?
Start Cosmos seeds indoors around Mar 13. Transplant outdoors after Apr 17. Expect first harvest around Jun 11.
What is the last frost date for Zone 7b?
The average last spring frost date for Zone 7b is Apr 10. The first fall frost averages Nov 7, giving a 211-day growing season.
Can I grow Cosmos in Zone 7b?
Yes. Cosmos needs 55 days to harvest. Zone 7b has a 211-day growing season, which is sufficient.
What is the best month to plant Cosmos in Zone 7b?
The best time to start Cosmos in Zone 7b is Mar. Begin seeds indoors around Mar 13, then transplant outdoors after the last frost date of Apr 10.
How long does Cosmos take to harvest?
Cosmos takes approximately 55 days from planting to harvest. In Zone 7b, expect your first harvest around Jun 11.
Plan Your Cosmos Garden
Track Cosmos from seed to harvest with personalized frost dates, watering recommendations, and companion planting visualization.
Start Free Cosmos Growing Guide