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When to Plant Lettuce in Yuma County, AZ

Yuma County, Arizona Zone 10a May

Yuma County, Arizona gardeners: here's your May plan

Your garden in Yuma County, Arizona is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost February 10
Avg. first frost December 1
Soil temp (4") 66°F
Watering Critical
Pest pressure High
Daylight 13.7 hrs
  1. It's harvest week for lettuce

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

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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.

Yuma County, Arizona is in USDA Zone 10a. The average last spring frost is February 10 and the first fall frost is December 1, giving you a growing season of approximately 294 days.

At an elevation of 4,781 feet, Yuma County receives approximately 9.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 92°F, providing good warmth for Lettuce during the growing season. 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.

Yuma County, AZ (Zone 10a) Year-round
294 days
Last Spring Frost February 10
294 growing days
First Fall Frost December 1
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Yuma County Soil Profile

Soil Type

Sandy Loam

Soil pH

6.9-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (191 days to spare)
Start indoors: Jan 6 Transplant: Feb 3 🍅 Harvest: Mar 10 – May 19
Recommended (50%) ✓ Fits season (189 days to spare)
Start indoors: Jan 13 Transplant: Feb 10 🍅 Harvest: Mar 17 – May 26
Safe Start (90%) ✓ Fits season (179 days to spare)
Start indoors: Feb 9 Transplant: Mar 9 🍅 Harvest: Apr 13 – Jun 22

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.

Soil Compatibility in Yuma County

How your county's soil matches Lettuce's growing requirements.

Soil pH

Your soil pH (6.9–8.4) is more alkaline than Lettuce prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Yuma County warms quickly in spring but drains fast. Lettuce will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is low (0.8%). Add 2-3 inches of compost before planting Lettuce.

How to Plant Lettuce

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Lettuce

12
successive plantings in your 294-day season

Sow every 3.4 weeks. Last sowing by Oct 02 to harvest before frost.

For a dedicated fall crop, sow by Oct 06.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.1″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,784 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Lettuce

Lettuce needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Lettuce Needs Rainfall You Supplement Action
Jan 0.6" 0" ❄️ Dormant
Feb 3" 0.5" 2.5" 🚿 Regular watering
Mar 3" 0.5" 2.5" 🚿 Regular watering
Apr 3" 0.3" 2.7" 🚿 Regular watering
May 3" 0.2" 2.8" 🚿 Regular watering
Jun 3" 0.3" 2.7" 🚿 Regular watering
Jul 3" 1.8" 1.2" 💧 Light watering
Aug 3" 1.9" 1.1" 💧 Light watering
Sep 3" 1.4" 1.6" 🚿 Regular watering
Oct 3" 0.8" 2.2" 🚿 Regular watering
Nov 3" 0.5" 2.5" 🚿 Regular watering
Dec 3" 0.6" 2.4" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Yuma County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Lettuce Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Lettuce needs ~855 GDD — county provides 5,605 GDD Excellent fit

Lettuce Planting Timeline — Yuma County, AZ

Lettuce Planting Calendar

Activity When Date Range
Start Indoors January 13 Jan 13 – Jan 27
Transplant Outdoors February 10 Feb 10 – Feb 24
Direct Sow January 20 Jan 20 – Feb 10
Harvest March 17 Mar 17 – May 26
Fall Sowing October 6 Oct 6 – Oct 20

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · 1-2 times/week

📅 Days to Maturity

30–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 10a

📆 Growing Season

294 days in Yuma County

Growing Tips for Lettuce in Yuma County

Direct sow Lettuce outdoors after February 10 in Yuma County when soil has warmed and frost danger has passed.

Sandy soil in Yuma County dries quickly — mulch Lettuce with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Summer highs in Yuma County reach 92°F — grow Lettuce as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 295.0-day season in Yuma County allows multiple plantings of Lettuce. Sow every 15.0 days for continuous harvest.

Common pests for Lettuce in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

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.

Recommended Lettuce Varieties for Yuma County

Bolt-resistant varieties for warm summers — grow as spring/fall crop

Jericho Muir Nevada New Red Fire

Companion Planting

Good Companions

Avoid Planting Near

  • Celery

Check more plant combinations with our Companion Planting Checker →

🌾 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 35°F, under 45% humidity.

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

Frequently Asked Questions

When should I plant Lettuce in Yuma County, AZ?

Yuma County is in Zone 10a with an average last frost of February 10. Plan your Lettuce planting based on this frost date — see the calendar above for exact timing.

What planting zone is Yuma County, AZ?

Yuma County, Arizona is in USDA Hardiness Zone 10a. The average last spring frost is February 10 and first fall frost is December 1.

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Your Yuma County Garden Planner — Free

A 24-page printable planner built for Yuma County (Zone 10a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.