Planting calendar
When to plant lettuce in Colorado
Colorado spans USDA hardiness zones 3-7a. Average last spring frost: 05-15. This calendar gives you the indoor start, transplant, and direct-sow dates for Lactuca sativa.
Colorado planting dates for lettuce
| Phase | Date in Colorado | Notes |
|---|---|---|
| Start seeds indoors | April 3 | 6 weeks before last frost |
| Transplant outdoors | May 1 | 2 weeks before last frost |
| Direct sow outside | May 1 | 2 weeks before last frost |
Why these dates
Lettuce is a cool-season crop. Above 75F it bolts (goes to seed). Plant in early spring and again in late summer for fall harvest. Provide afternoon shade in midsummer to extend the season.
The dates above are anchored to Colorado's average last spring frost date of 05-15, with offsets standard across university Extension publications. For zone-specific local timing, use the frost date lookup tool with your ZIP code.
More on growing lettuce
The full growing guide for lettuce - varieties, soil, fertilization, pests, harvest, storage - is here: Lettuce growing guide.
More Colorado planting information
- Full Colorado planting calendar (all crops + ornamentals)
- Find your exact USDA zone by ZIP
- Look up your average frost dates
- Seed starting timeline calculator