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When to Plant Lettuce in Conejos County, CO

Lettuce is a fast-growing cool-season green available in leaf, romaine, butterhead, and crisphead types. It is the foundation of salads and one of the easiest crops to grow.

Conejos County, Colorado is in USDA Zone 4b. The average last spring frost is June 9 and the first fall frost is September 17, giving you a growing season of approximately 100 days.

At an elevation of 6,770 feet, Conejos County receives approximately 24.1 inches of rainfall annually with predominantly loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Lettuce to ensure they mature before fall.

Conejos County, CO (Zone 4b) Short season
100 days
Last Spring Frost June 9
100 growing days
First Fall Frost September 17

Conejos County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (0 days to spare)
Start indoors: Apr 18 Transplant: May 30 🍅 Harvest: Jul 4 – Sep 12
Recommended (50%) ✗ May not fit
Start indoors: Apr 28 Transplant: Jun 9 🍅 Harvest: Jul 14 – Sep 22
Safe Start (90%) ✗ May not fit
Start indoors: May 11 Transplant: Jun 22 🍅 Harvest: Jul 27 – Oct 5

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Lettuce needs ~518 GDD — county provides 1,150 GDD Excellent fit

Lettuce Planting Timeline โ€” Conejos County, CO

Lettuce Planting Calendar

Activity When Date Range
Start Indoors April 28 Apr 28 โ€“ May 12
Transplant Outdoors June 9 Jun 9 โ€“ Jun 23
Direct Sow June 2 Jun 2 โ€“ Jun 23
Fall Sowing June 25 Jun 25 โ€“ Jul 9
Harvest July 14 Jul 14 โ€“ Sep 22

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Start Indoors
May Start Indoors
June Transplant Outdoors Direct Sow Fall Sowing
July Fall Sowing Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

30โ€“60 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 4b

Growing Season

100 days

Growing Tips for Conejos County

Sow seeds directly every 2 weeks for continuous harvest. Provide afternoon shade in warm weather to delay bolting. Harvest in the morning for crispest leaves.

Companion Planting

Good Companions

Avoid Planting Near

  • Celery

Level Up Your Garden

๐ŸŒพ Save Your Own Lettuce Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let plants bolt and flower. Harvest seed heads when fluffy.
Storage Store airtight; viable 6 years at 35ยฐF, under 45% humidity.

Very easy to save. Let a few plants bolt each season.

Frequently Asked Questions

When should I plant Lettuce in Conejos County, CO?

Conejos County is in Zone 4b with an average last frost of June 9. Plan your Lettuce planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Conejos County, CO?

Conejos County, Colorado is in USDA Hardiness Zone 4b. The average last spring frost is June 9 and first fall frost is September 17.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Conejos County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Conejos County, CO. Local conditions may vary. Last updated: April 2026.