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When to Plant Spinach in La Paz County, AZ

La Paz County, Arizona Zone 9b April

Top priorities for La Paz County, Arizona gardeners in April

Each item below is timed to La Paz County, Arizona's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost February 2
Avg. first frost December 6
Soil temp (4") 55°F
Watering Critical
Pest pressure High
Daylight 12.8 hrs
  1. Start harvesting spinach

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

May prep starts now
  • First harvests: spinach

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Spinach is a nutrient-packed cool-season green that grows quickly in spring and fall. It is rich in iron, vitamins, and antioxidants and excellent raw or cooked.

La Paz County, Arizona is in USDA Zone 9b. The average last spring frost is February 2 and the first fall frost is December 6, giving you a growing season of approximately 307 days.

At an elevation of 4,875 feet, La Paz County receives approximately 17.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 105°F, so Spinach may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Spinach will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Spinach successfully. Mulch heavily to conserve soil moisture.

La Paz County, AZ (Zone 9b) Year-round
307 days
Last Spring Frost February 2
307 growing days
First Fall Frost December 6

La Paz County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (221 days to spare)
Start indoors: Dec 21 Transplant: Jan 18 🍅 Harvest: Feb 22 – Apr 26
Recommended (50%) ✓ Fits season (209 days to spare)
Start indoors: Jan 5 Transplant: Feb 2 🍅 Harvest: Mar 9 – May 11
Safe Start (90%) ✓ Fits season (205 days to spare)
Start indoors: Jan 30 Transplant: Feb 27 🍅 Harvest: Apr 3 – Jun 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.

Soil Compatibility in La Paz County

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

Soil pH

Your soil pH (7.2–8.3) is more alkaline than Spinach prefers (6.5–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is low (0.7%). Add 2-3 inches of compost before planting Spinach.

How to Plant Spinach

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 Spinach

10
successive plantings in your 307-day season

Sow every 4 weeks. Last sowing by Oct 17 to harvest before frost.

For a dedicated fall crop, sow by Oct 11.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.2″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,522 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Spinach

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

Month Spinach Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 3" 0.9" 2.1" 🚿 Regular watering
Mar 3" 1" 2" 🚿 Regular watering
Apr 3" 0.6" 2.4" 🚿 Regular watering
May 3" 0.4" 2.6" 🚿 Regular watering
Jun 3" 0.7" 2.3" 🚿 Regular watering
Jul 3" 2.5" 0.5" 💧 Light watering
Aug 3" 3.7" 0" ✅ Rainfall sufficient
Sep 3" 2.5" 0.5" 💧 Light watering
Oct 3" 1.6" 1.4" 💧 Light watering
Nov 3" 1" 2" 🚿 Regular watering
Dec 3" 1.2" 1.8" 🚿 Regular watering

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

Spinach 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.

Spinach needs ~1,222 GDD — county provides 8,855 GDD Excellent fit

Spinach Planting Timeline — La Paz County, AZ

Spinach Planting Calendar

Activity When Date Range
Start Indoors January 5 Jan 5 – Jan 19
Transplant Outdoors February 2 Feb 2 – Feb 16
Direct Sow January 12 Jan 12 – Feb 2
Harvest March 9 Mar 9 – May 11
Fall Sowing October 11 Oct 11 – Oct 25

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · 1-2 times/week

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

307 days in La Paz County

Growing Tips for Spinach in La Paz County

Direct sow Spinach outdoors after February 02 in La Paz County when soil has warmed and frost danger has passed.

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

Summer highs in La Paz County reach 105°F — grow Spinach as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 308.0-day season in La Paz County allows multiple plantings of Spinach. Sow every 17.0 days for continuous harvest.

General growing tips

Direct sow as soon as soil can be worked in spring. Plant in partial shade for summer crops to delay bolting. Succession plant every 2 weeks for continuous harvest.

Recommended Spinach Varieties for La Paz County

Slow-bolting spinach for warm springs — best as fall crop here

Bloomsdale Long Standing Tyee Space

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Spinach Seeds
Life Cycle Annual
Pollination Wind Pollinated
How to Collect Let plants bolt. Harvest seed stalks when seeds turn tan.
Storage Store airtight; viable 5 years at 35°F, under 45% humidity.

Wind pollinated — isolate 1/2 mile for purity. Easy to let bolt in heat.

Frequently Asked Questions

When should I plant Spinach in La Paz County, AZ?

La Paz County is in Zone 9b with an average last frost of February 2. Plan your Spinach planting based on this frost date — see the calendar above for exact timing.

What planting zone is La Paz County, AZ?

La Paz County, Arizona is in USDA Hardiness Zone 9b. The average last spring frost is February 2 and first fall frost is December 6.

🌱

Your La Paz County Garden Planner — Free

A 24-page printable planner built for La Paz County (Zone 9b). 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 La Paz County, AZ. Local conditions may vary. Last updated: April 2026.

Sources & credits

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