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When to Plant Potatoes in La Paz County, AZ

La Paz County, Arizona Zone 9a May

Your May game plan for La Paz County, Arizona

Here's what deserves your attention in La Paz County, Arizona this month. Everything below is tailored to Zone 9a and timed around your local frost dates.

Avg. last frost February 2
Avg. first frost December 6
Soil temp (4") 62°F
Watering Critical
Pest pressure High
Daylight 13.8 hrs
  1. Collect potatoes at their peak

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

Before June arrives, get these ready
  • First harvests: potatoes

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Potatoes are a versatile staple crop that produces tubers underground. They come in hundreds of varieties with varying colors, textures, and maturity dates.

La Paz County, Arizona is in USDA Zone 9a. 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 Potatoes may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Potatoes will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Potatoes successfully. Mulch heavily to conserve soil moisture.

La Paz County, AZ (Zone 9a) 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 (172 days to spare)
Start indoors: Dec 7 Transplant: Jan 25 🍅 Harvest: Apr 5 – Jun 14
Recommended (50%) ✓ Fits season (160 days to spare)
Start indoors: Dec 22 Transplant: Feb 9 🍅 Harvest: Apr 20 – Jun 29
Safe Start (90%) ✓ Fits season (156 days to spare)
Start indoors: Jan 16 Transplant: Mar 6 🍅 Harvest: May 15 – Jul 24

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 Potatoes's growing requirements.

Soil pH

Your soil pH (7.2–8.3) is more alkaline than Potatoes prefers (5.0–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in La Paz County warms quickly in spring but drains fast. Potatoes 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 Potatoes.

How to Plant Potatoes

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Potatoes

5
successive plantings in your 307-day season

Sow every 8 weeks. Last sowing by Aug 08 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.2″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 2,509 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Potatoes

Potatoes needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Potatoes Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 4.3" 0.9" 3.4" 🚿 Regular watering
Mar 4.3" 1" 3.3" 🚿 Regular watering
Apr 4.3" 0.6" 3.7" 🚿 Regular watering
May 4.3" 0.4" 3.9" 🚿 Regular watering
Jun 4.3" 0.7" 3.6" 🚿 Regular watering
Jul 4.3" 2.5" 1.8" 💧 Light watering
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 2.5" 1.8" 💧 Light watering
Oct 4.3" 1.6" 2.7" 🚿 Regular watering
Nov 4.3" 1" 3.3" 🚿 Regular watering
Dec 4.3" 1.2" 3.1" 🚿 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.

Potatoes 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.

Potatoes needs ~2,731 GDD — county provides 8,855 GDD Excellent fit

Potatoes Planting Timeline — La Paz County, AZ

Potatoes Planting Calendar

Activity When Date Range
Start Indoors December 22 Dec 22 – Jan 5
Transplant Outdoors February 9 Feb 9 – Feb 23
Direct Sow February 2 Feb 2 – Feb 23
Harvest April 20 Apr 20 – Jun 29

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

70–120 days

🧪 Soil pH

Needs 5–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

307 days in La Paz County

Growing Tips for Potatoes in La Paz County

Direct sow Potatoes 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 Potatoes with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 105°F in La Paz County, provide afternoon shade for Potatoes and water deeply in the morning.

Common pests for Potatoes in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

La Paz County receives only 17" of rain annually. Potatoes needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant seed potatoes (not grocery store potatoes) 4 inches deep in spring. Hill soil around stems as plants grow to prevent greening. Stop watering when plants die back.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Cucumber
  • Squash Summer

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

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

La Paz County is in Zone 9a with an average last frost of February 2. Plan your Potatoes 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 9a. 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 9a). 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: May 2026.

Sources & credits

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