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When to Plant Lemon Thyme in Maricopa County, AZ

Maricopa County, Arizona Zone 9b May

May to-do list for Maricopa 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 January 31
Avg. first frost December 6
Soil temp (4") 66°F
Watering Critical
Pest pressure High
Daylight 13.7 hrs
  1. Collect lemon thyme at their peak

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

Coming up in June — start thinking about
  • First harvests: lemon thyme

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Lemon thyme is a low-growing perennial herb with tiny, citrus-scented leaves. It combines the savory quality of thyme with a bright lemon flavor, excellent with fish and poultry.

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 Lemon Thyme may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Lemon Thyme will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Lemon Thyme 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 (178 days to spare)
Transplant: Jan 24 🍅 Harvest: Apr 4 – Jun 6
Recommended (50%) ✓ Fits season (169 days to spare)
Transplant: Feb 7 🍅 Harvest: Apr 18 – Jun 20
Safe Start (90%) ✓ Fits season (164 days to spare)
Transplant: Mar 6 🍅 Harvest: May 15 – Jul 17

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 Lemon Thyme's growing requirements.

Soil pH

Your soil pH (7.2–8.5) overlaps with Lemon Thyme's range (6.0–8.0), though not a perfect match.

Soil Texture

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

How to Plant Lemon Thyme

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

Succession Planting Lemon Thyme

5
successive plantings in your 309-day season

Sow every 8 weeks. Last sowing by Sep 07 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.2″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 1,095 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Lemon Thyme

Lemon Thyme needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Lemon Thyme Needs Rainfall You Supplement Action
Jan 2.2" 0.9" 1.3" 🚿 Regular watering
Feb 2.2" 0.8" 1.4" 🚿 Regular watering
Mar 2.2" 0.7" 1.5" 🚿 Regular watering
Apr 2.2" 0.5" 1.7" 🚿 Regular watering
May 2.2" 0.3" 1.9" 🚿 Regular watering
Jun 2.2" 0.4" 1.8" 🚿 Regular watering
Jul 2.2" 2.1" 0.1" 💧 Light watering
Aug 2.2" 2.3" 0" ✅ Rainfall sufficient
Sep 2.2" 1.9" 0.3" 💧 Light watering
Oct 2.2" 1.2" 1" 💧 Light watering
Nov 2.2" 0.6" 1.6" 🚿 Regular watering
Dec 2.2" 0.8" 1.4" 🚿 Regular 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.

Lemon Thyme 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.

Lemon Thyme needs ~2,480 GDD — county provides 9,610 GDD Excellent fit

Lemon Thyme Planting Timeline — Maricopa County, AZ

Lemon Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors February 7 Feb 7 – Feb 21
Harvest April 18 Apr 18 – Jun 20

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · 1-2 times/week

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

309 days in Maricopa County

Growing Tips for Lemon Thyme in Maricopa County

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

Sandy soil in Maricopa County dries quickly — mulch Lemon Thyme 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 Lemon Thyme and water deeply in the morning.

Maricopa County receives only 12" of rain annually. Lemon Thyme needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start from cuttings or divisions. Plant in well-drained soil. Trim back after flowering. Use as a fragrant ground cover or edging plant along garden paths.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lemon Thyme in Maricopa County, AZ?

Maricopa County is in Zone 9b with an average last frost of January 31. Plan your Lemon Thyme 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.