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When to Plant Kale in La Paz County, AZ

La Paz County, Arizona Zone 9a May

May to-do list for La Paz County, Arizona

May is a pivotal month for La Paz County, Arizona gardens. Focus on these tasks first and you'll set up the rest of the season for success.

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. It's harvest week for kale

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

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Kale is an exceptionally hardy, nutrient-dense green available in curly, lacinato, and Russian varieties. It tolerates heavy frost and often tastes sweeter after cold exposure.

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 Kale may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Kale will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Kale 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
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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 (207 days to spare)
Start indoors: Dec 21 Transplant: Jan 18 🍅 Harvest: Mar 15 – May 10
Recommended (50%) ✓ Fits season (195 days to spare)
Start indoors: Jan 5 Transplant: Feb 2 🍅 Harvest: Mar 30 – May 25
Safe Start (90%) ✓ Fits season (191 days to spare)
Start indoors: Jan 30 Transplant: Feb 27 🍅 Harvest: Apr 24 – Jun 19

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 Kale's growing requirements.

Soil pH

Your soil pH (7.2–8.3) is more alkaline than Kale prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

How to Plant Kale

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

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

Succession Planting Kale

7
successive plantings in your 307-day season

Sow every 5.7 weeks. Last sowing by Sep 27 to harvest before frost.

For a dedicated fall crop, sow by Oct 11.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.2″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,851 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Kale

Kale needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Kale Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 3.5" 0.9" 2.6" 🚿 Regular watering
Mar 3.5" 1" 2.5" 🚿 Regular watering
Apr 3.5" 0.6" 2.9" 🚿 Regular watering
May 3.5" 0.4" 3.1" 🚿 Regular watering
Jun 3.5" 0.7" 2.8" 🚿 Regular watering
Jul 3.5" 2.5" 1" 💧 Light watering
Aug 3.5" 3.7" 0" ✅ Rainfall sufficient
Sep 3.5" 2.5" 1" 💧 Light watering
Oct 3.5" 1.6" 1.9" 🚿 Regular watering
Nov 3.5" 1" 2.5" 🚿 Regular watering
Dec 3.5" 1.2" 2.3" 🚿 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.

Kale 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.

Kale needs ~1,725 GDD — county provides 8,855 GDD Excellent fit

Kale Planting Timeline — La Paz County, AZ

Kale 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 30 Mar 30 – May 25
Fall Sowing October 11 Oct 11 – Oct 25

Plant 1" deep · 15" apart · Rows 24" 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

Full Sun (6-8+ hours)

💧 Water

0.8"/week · 1-2 times/week

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

307 days in La Paz County

Growing Tips for Kale in La Paz County

Direct sow Kale 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 Kale 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 Kale as a spring or fall crop. Use shade cloth if planting in summer.

Common pests for Kale in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow or transplant in early spring or late summer. Harvest outer leaves first to keep plants productive. Kale overwinters in many climates and can provide greens all year.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Kale Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Allow 2nd year flower stalks to dry. Harvest pods when tan.
Storage Store airtight; viable 5 years at 35°F, under 50% humidity.

Isolate 1/2 mile from other brassicas (broccoli, cabbage, etc.) — they all cross.

Frequently Asked Questions

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

La Paz County is in Zone 9a with an average last frost of February 2. Plan your Kale 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.

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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.