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When to Plant Thyme in Pinal County, AZ

Pinal County, Arizona Zone 9a May

Pinal County, Arizona gardeners: here's your May plan

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

Avg. last frost February 23
Avg. first frost November 27
Soil temp (4") 66°F
Watering Critical
Pest pressure High
Daylight 13.7 hrs
  1. Bring in the thyme

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

Looking ahead to June
  • First harvests: thyme

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Thyme is a low-growing perennial herb with tiny, aromatic leaves and a warm, earthy flavor. It is one of the most versatile culinary and medicinal herbs.

Pinal County, Arizona is in USDA Zone 9a. The average last spring frost is February 23 and the first fall frost is November 27, giving you a growing season of approximately 277 days.

At an elevation of 3,959 feet, Pinal County receives approximately 15.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 98°F, so Thyme may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Thyme will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Thyme successfully. Mulch heavily to conserve soil moisture.

Pinal County, AZ (Zone 9a) Year-round
277 days
Last Spring Frost February 23
277 growing days
First Fall Frost November 27

Pinal County Soil Profile

Soil Type

Sandy Loam

Soil pH

7-8.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (145 days to spare)
Transplant: Feb 17 🍅 Harvest: Apr 28 – Jun 30
Recommended (50%) ✓ Fits season (137 days to spare)
Transplant: Mar 2 🍅 Harvest: May 11 – Jul 13
Safe Start (90%) ✓ Fits season (125 days to spare)
Transplant: Mar 31 🍅 Harvest: Jun 9 – Aug 11

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 Pinal County

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

Soil pH

Your soil pH (7.0–8.6) overlaps with Thyme's range (6.0–8.0), though not a perfect match.

Soil Texture

Sandy soil in Pinal County warms quickly in spring but drains fast. Thyme will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Thyme.

Organic Matter

Organic matter is low (0.7%). Add 2-3 inches of compost before planting Thyme.

How to Plant Thyme

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

Succession Planting Thyme

4
successive plantings in your 277-day season

Sow every 8 weeks. Last sowing by Aug 29 to harvest before frost.

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 449 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Thyme

Thyme 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 Thyme Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 1.3" 1" 0.3" 💧 Light watering
Mar 1.3" 0.8" 0.5" 💧 Light watering
Apr 1.3" 0.5" 0.8" 🚿 Regular watering
May 1.3" 0.3" 1" 🚿 Regular watering
Jun 1.3" 0.5" 0.8" 🚿 Regular watering
Jul 1.3" 3" 0" ✅ Rainfall sufficient
Aug 1.3" 3.5" 0" ✅ Rainfall sufficient
Sep 1.3" 1.9" 0" ✅ Rainfall sufficient
Oct 1.3" 1.5" 0" ✅ Rainfall sufficient
Nov 1.3" 0.8" 0.5" 💧 Light watering
Dec 1" 0" ❄️ Dormant

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

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.

Thyme needs ~1,880 GDD — county provides 6,533 GDD Excellent fit

Thyme Planting Timeline — Pinal County, AZ

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors March 2 Mar 2 – Mar 16
Harvest May 11 May 11 – Jul 13

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.3"/week · Only during dry spells

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

277 days in Pinal County

Growing Tips for Thyme in Pinal County

Direct sow Thyme outdoors after February 23 in Pinal County when soil has warmed and frost danger has passed.

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

With summer highs reaching 98°F in Pinal County, provide afternoon shade for Thyme and water deeply in the morning.

General growing tips

Start from seed, cuttings, or divisions. Plant in well-drained, lean soil. Prune lightly after flowering. Replace plants every 3-4 years when they become woody.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Thyme in Pinal County, AZ?

Pinal County is in Zone 9a with an average last frost of February 23. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.

What planting zone is Pinal County, AZ?

Pinal County, Arizona is in USDA Hardiness Zone 9a. The average last spring frost is February 23 and first fall frost is November 27.

🌱

Your Pinal County Garden Planner — Free

A 24-page printable planner built for Pinal 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 Pinal 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.