Quick planting window
| Start indoors | April to May |
|---|---|
| Transplant | April to May |
| Sow seeds | April to May |
| Estimated harvest | June to July |
| Risk | Low risk |
Month calendar
Scan the year by month to see seed starting, sowing, transplanting, and harvest timing.
Lettuce is a reasonable spring choice for Colorado if you adjust for your local microclimate.
Next: ZIP code personalization
This is a state-level planning window based on typical frost timing and crop rules. Use local Extension guidance or a ZIP code frost-date tool before planting.
Planning notes
Days to maturity
45
Covered states
Colorado
Frost window
May to June / September to October
Front Range, mountain, and western slope gardens can have very different timing.
Lettuce growing notes
The calendar window is only the first step. These growing details affect survival, plant vigor, and harvest quality.
Sun
Full sun in cool weather; afternoon shade in heat.
Soil
Loose, fertile soil that stays evenly moist.
Spacing
6-12 inches depending on head size.
Container
Very container friendly; shallow boxes work for leaf lettuce.
Watering
Keep moist to reduce bitterness and bolting.
Common mistake
Planting too late into summer heat.
Beginner tip
Sow small batches every 1-2 weeks for a longer harvest.
Month window table
| Crop | Spring transplant / sow | Spring harvest | Fall transplant / sow | Fall harvest |
|---|---|---|---|---|
| Lettuce | April to May | June to July | August to September | September to October |
Sources and limits
This page uses Colorado state-level frost windows, USDA zone ranges, and crop rules for planning. It does not replace local Extension or county-level guidance.
FAQ
When should I start lettuce seeds indoors in Colorado?
For spring, the indoor seed-starting window is about April to May. Move later if your local frost date is later than the state average.
When should I transplant lettuce in Colorado?
For spring, the transplant window is about April to May. Harden seedlings off before planting outside.
Can I sow lettuce outdoors in Colorado?
Yes. The spring outdoor sowing window is about April to May, assuming soil and night temperatures are suitable.
When can I harvest lettuce in Colorado?
Spring planting estimates a harvest around June to July; fall planting estimates about September to October. Variety and weather can shift this by several weeks.
Is lettuce risky in Colorado?
Lettuce is a reasonable spring choice for Colorado if you adjust for your local microclimate. For fall: Lettuce is a reasonable fall choice for Colorado if you adjust for your local microclimate.
Do local differences inside Colorado matter?
Front Range, mountain, and western slope gardens can have very different timing. Treat this as a state-level starter window and confirm with a local Extension or frost-date tool before planting.
What growing details matter most for lettuce?
Full sun in cool weather; afternoon shade in heat. Loose, fertile soil that stays evenly moist. Common mistake: Planting too late into summer heat.
Is this ZIP-code accurate?
No. This page uses state-level windows; ZIP-code frost dates, USDA zone matching, and reminder calendars are planned for the next phase.