When to Plant Lettuce in Pima County, AZ
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.
Pima County, Arizona is in USDA Zone 9a. The average last spring frost is April 1 and the first fall frost is November 9, giving you a growing season of approximately 222 days.
At an elevation of 4,327 feet, Pima County receives approximately 14.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 103°F, so Lettuce may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Lettuce will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Lettuce successfully. Mulch heavily to conserve soil moisture.
Pima County Soil Profile
Soil Type
Sandy Loam
Soil pH
6.8-8.3
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 10/10 — consider drought-tolerant varieties and mulching
Lettuce Planting Timeline — Pima County, AZ
Lettuce Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 4 | Mar 4 – Mar 18 |
| Transplant Outdoors | April 1 | Apr 1 – Apr 15 |
| Direct Sow | March 11 | Mar 11 – Apr 1 |
| Fall Sowing | September 14 | Sep 14 – Sep 28 |
| Harvest | May 6 | May 6 – Jul 15 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | — |
| September | Fall Sowing |
| 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 9a
Growing Season
222 days
Growing Tips for Pima 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 Pima County, AZ?
Pima County is in Zone 9a with an average last frost of April 1. Plan your Lettuce planting based on this frost date — see the calendar above for exact timing.
What planting zone is Pima County, AZ?
Pima County, Arizona is in USDA Hardiness Zone 9a. The average last spring frost is April 1 and first fall frost is November 9.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Pima County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.
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