When to Plant Lettuce in Arapahoe 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.
Arapahoe County, Colorado is in USDA Zone 5b. The average last spring frost is May 10 and the first fall frost is October 7, giving you a growing season of approximately 150 days.
At an elevation of 7,205 feet, Arapahoe County receives approximately 21.4 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Lettuce during the growing season.
Arapahoe County Soil Profile
Soil Type
Loam
Soil pH
6.2-8.3
Drainage
Well Drained
Plant Planting Risk Windows
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
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Lettuce Planting Timeline — Arapahoe County, CO
Lettuce Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 5 | Apr 5 – Apr 19 |
| Transplant Outdoors | May 10 | May 10 – May 24 |
| Direct Sow | April 26 | Apr 26 – May 17 |
| Fall Sowing | July 29 | Jul 29 – Aug 12 |
| Harvest | June 14 | Jun 14 – Aug 23 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Fall Sowing Harvest |
| August | Fall Sowing Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Partial Shade (3-6 hours)
Water
Moderate — regular watering
Days to Maturity
30–60 days
Soil pH
6 – 7
USDA Zone
Zone 5b
Growing Season
150 days
Growing Tips for Arapahoe 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
Level Up Your Garden
Very easy to save. Let a few plants bolt each season.
Lettuce in Other Locations
Frequently Asked Questions
When should I plant Lettuce in Arapahoe County, CO?
Arapahoe County is in Zone 5b with an average last frost of May 10. Plan your Lettuce planting based on this frost date — see the calendar above for exact timing.
What planting zone is Arapahoe County, CO?
Arapahoe County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 10 and first fall frost is October 7.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Arapahoe County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.
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