When to Plant Fennel in Fort Collins, Colorado (80521)
Location
Fort Collins, Colorado
ZIP Code
80521
USDA Zone
5b
Last Frost
Saturday, April 25, 2026
📅 Planting Calendar
Start Seeds Indoors Saturday, March 28, 2026
Transplant Outdoors Saturday, April 11, 2026
Pro Tip: Start Fennel seeds indoors 4 weeks before your last frost date for best results.
🌿 Plant Details
Scientific Name Foeniculum vulgare
Days to Maturity 80 days
☀️ Growing Requirements
☀️
Sun
Full Sun
💧
Water
Regular
Seeds typically germinate in 7-14 days
🤝 Good Companions
Dill
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Growing Fennel in Zone 5b
Fennel (Foeniculum vulgare) is a popular garden vegetable. In Fort Collins, Colorado, which is in USDA Hardiness Zone 5b, you should start seeds indoors around Saturday, March 28, 2026.
Your average last frost date is Saturday, April 25, 2026. Plan to transplant your Fennel seedlings outdoors around Saturday, April 11, 2026, about -2 weeks after your last frost date.