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When to Plant Lavender in Maricopa County, AZ

Maricopa County, Arizona Zone 9b May

What to do in May

Your Maricopa County, Arizona garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost January 31
Avg. first frost December 6
Soil temp (4") 66°F
Watering Critical
Pest pressure High
Daylight 13.7 hrs
  1. It's harvest week for lavender

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

Looking ahead to June
  • First harvests: lavender

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Lavender is a fragrant perennial herb with silvery foliage and purple flower spikes. It is prized for its essential oils, culinary uses, and ornamental beauty.

Maricopa County, Arizona is in USDA Zone 9b. The average last spring frost is January 31 and the first fall frost is December 6, giving you a growing season of approximately 309 days.

At an elevation of 4,014 feet, Maricopa County receives approximately 12.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 108°F, so Lavender may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Lavender will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Lavender successfully. Mulch heavily to conserve soil moisture.

Maricopa County, AZ (Zone 9b) Year-round
309 days
Last Spring Frost January 31
309 growing days
First Fall Frost December 6

Maricopa County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (66 days to spare)
Transplant: Jan 24 🍅 Harvest: Apr 25 – Sep 26
Recommended (50%) ✓ Fits season (57 days to spare)
Transplant: Feb 7 🍅 Harvest: May 9 – Oct 10
Safe Start (90%) ✓ Fits season (52 days to spare)
Transplant: Mar 6 🍅 Harvest: Jun 5 – Nov 6

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 Maricopa County

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

Soil pH

Your soil pH (7.2–8.5) overlaps with Lavender's range (6.5–8.0), though not a perfect match.

Soil Texture

Sandy soil in Maricopa County warms quickly in spring but drains fast. Lavender 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 Lavender.

How to Plant Lavender

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

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
0.2″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 433 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Lavender

Lavender needs approximately 0.3 inches of water per week (1.3" per month). Here's how your county's rainfall compares month by month.

Month Lavender Needs Rainfall You Supplement Action
Jan 1.3" 0.9" 0.4" 💧 Light watering
Feb 1.3" 0.8" 0.5" 💧 Light watering
Mar 1.3" 0.7" 0.6" 💧 Light watering
Apr 1.3" 0.5" 0.8" 🚿 Regular watering
May 1.3" 0.3" 1" 🚿 Regular watering
Jun 1.3" 0.4" 0.9" 🚿 Regular watering
Jul 1.3" 2.1" 0" ✅ Rainfall sufficient
Aug 1.3" 2.3" 0" ✅ Rainfall sufficient
Sep 1.3" 1.9" 0" ✅ Rainfall sufficient
Oct 1.3" 1.2" 0.1" 💧 Light watering
Nov 1.3" 0.6" 0.7" 🚿 Regular watering
Dec 1.3" 0.8" 0.5" 💧 Light watering

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

Lavender 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.

Lavender needs ~4,495 GDD — county provides 9,610 GDD Excellent fit

Lavender Planting Timeline — Maricopa County, AZ

Lavender Planting Calendar

Activity When Date Range
Transplant Outdoors February 7 Feb 7 – Feb 21
Harvest May 9 May 9 – Oct 10

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.3"/week · Only during dry spells

📅 Days to Maturity

90–200 days

🧪 Soil pH

Needs 6.5–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

309 days in Maricopa County

Growing Tips for Lavender in Maricopa County

Direct sow Lavender outdoors after January 31 in Maricopa County when soil has warmed and frost danger has passed.

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

With summer highs reaching 108°F in Maricopa County, provide afternoon shade for Lavender and water deeply in the morning.

General growing tips

Plant in well-drained, sandy soil. Avoid heavy mulching around the crown. Prune after flowering but do not cut into old wood. Lavender resents wet winter conditions.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lavender in Maricopa County, AZ?

Maricopa County is in Zone 9b with an average last frost of January 31. Plan your Lavender planting based on this frost date — see the calendar above for exact timing.

What planting zone is Maricopa County, AZ?

Maricopa County, Arizona is in USDA Hardiness Zone 9b. The average last spring frost is January 31 and first fall frost is December 6.

🌱

Your Maricopa County Garden Planner — Free

A 24-page printable planner built for Maricopa 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 Maricopa 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.