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When to Plant Basil in La Paz County, AZ

La Paz County, Arizona Zone 9a May

May to-do list for La Paz County, Arizona

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

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. Pick basil

    If you can't use it all right away, check the food-preservation section of your planner.

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

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Basil is a fragrant warm-season herb essential to Italian and Thai cuisines. It comes in many varieties including sweet, Thai, purple, and lemon types.

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 Basil may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Basil will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Basil 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 (193 days to spare)
Start indoors: Dec 7 Transplant: Jan 25 🍅 Harvest: Mar 22 – May 24
Recommended (50%) ✓ Fits season (181 days to spare)
Start indoors: Dec 22 Transplant: Feb 9 🍅 Harvest: Apr 6 – Jun 8
Safe Start (90%) ✓ Fits season (177 days to spare)
Start indoors: Jan 16 Transplant: Mar 6 🍅 Harvest: May 1 – Jul 3

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 Basil's growing requirements.

Soil pH

Your soil pH (7.2–8.3) is more alkaline than Basil prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

How to Plant Basil

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Basil

7
successive plantings in your 307-day season

Sow every 5.7 weeks. Last sowing by Sep 22 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.2″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 1,193 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Basil

Basil needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Basil Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 2.6" 0.9" 1.7" 🚿 Regular watering
Mar 2.6" 1" 1.6" 🚿 Regular watering
Apr 2.6" 0.6" 2" 🚿 Regular watering
May 2.6" 0.4" 2.2" 🚿 Regular watering
Jun 2.6" 0.7" 1.9" 🚿 Regular watering
Jul 2.6" 2.5" 0.1" 💧 Light watering
Aug 2.6" 3.7" 0" ✅ Rainfall sufficient
Sep 2.6" 2.5" 0.1" 💧 Light watering
Oct 2.6" 1.6" 1" 💧 Light watering
Nov 2.6" 1" 1.6" 🚿 Regular watering
Dec 2.6" 1.2" 1.4" 🚿 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.

Basil 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.

Basil needs ~1,797 GDD — county provides 8,855 GDD Excellent fit

Basil Planting Timeline — La Paz County, AZ

Basil 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 9 Feb 9 – Mar 2
Harvest April 6 Apr 6 – Jun 8

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · 1-2 times/week

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

307 days in La Paz County

Growing Tips for Basil in La Paz County

Direct sow Basil 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 Basil 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 Basil and water deeply in the morning.

General growing tips

Start seeds indoors or direct sow after last frost. Pinch flower buds to extend leaf production. Harvest leaves from the top down, cutting just above a leaf pair.

Companion Planting

Good Companions

Avoid Planting Near

  • Rue
  • Sage

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Basil Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let flower spikes dry brown on the plant.
Storage Store airtight; viable 5 years at 35°F, under 45% humidity.

Isolate 150 ft between varieties. Different basil species can cross.

Frequently Asked Questions

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

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