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When to plant Thyme in Monterey County, CA

In Monterey County, Thyme is a single-season spring crop — there's no second fall window. Plant March 20–April 3 for an 70–90-day harvest, finishing well before the November 17 first frost.

When to Plant Thyme in Monterey County, CA

Thyme
Monterey County, California Zone 9b July

July in Monterey County, California — your action list

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Avg. last frost March 13
Avg. first frost November 17
Soil temp (4") 95°F
Watering Critical
Pest pressure High
Daylight 14.2 hrs
  1. Basket week: thyme

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

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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.

Monterey County, California is in USDA Zone 9b. The average last spring frost is March 13 and the first fall frost is November 17, giving you a growing season of approximately 249 days.

At an elevation of 260 feet, Monterey County receives approximately 12.5 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Thyme during the growing season. With low rainfall, drip irrigation is essential for growing Thyme successfully. Mulch heavily to conserve soil moisture.

Monterey County, CA (Zone 9b) Long season
249 days
Last Spring Frost March 13
249 growing days
First Fall Frost November 17

Monterey County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.2

Drainage

Well Drained

Thyme Planting Risk Windows

Early Start (70% safe) ✓ Fits season (108 days to spare)
Transplant: Mar 6 🍅 Harvest: May 15 – Jul 17
Recommended (50%) ✓ Fits season (109 days to spare)
Transplant: Mar 20 🍅 Harvest: May 29 – Jul 31
Safe Start (90%) ✓ Fits season (74 days to spare)
Transplant: May 24 🍅 Harvest: Aug 2 – Oct 4

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 Monterey County

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

Soil pH

Your soil pH (6.7–7.2) is within Thyme's preferred range (6.0–8.0).

Soil Texture

The loam soil in Monterey County is excellent for Thyme — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Thyme.

How to Plant Thyme

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

Succession Planting Thyme

4
successive plantings in your 249-day season

Sow every 8 weeks. Last sowing by Aug 19 to harvest before frost.

Thyme Water Budget

Plant needs
0.3″/week
Rainfall provides
0.2″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 237 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 2.7" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 1.3" 2.1" 0" ✅ Rainfall sufficient
Apr 1.3" 1" 0.3" 💧 Light watering
May 1.3" 0.3" 1" 🚿 Regular watering
Jun 1.3" 0.1" 1.2" 🚿 Regular watering
Jul 1.3" 0" 1.3" 🚿 Regular watering
Aug 1.3" 0" 1.3" 🚿 Regular watering
Sep 1.3" 0.1" 1.2" 🚿 Regular watering
Oct 1.3" 0.5" 0.8" 🚿 Regular watering
Nov 1.3" 1.2" 0.1" 💧 Light watering
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Monterey 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 ~1,580 GDD — county provides 4,917 GDD Excellent fit

Thyme Planting Timeline — Monterey County, CA

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors March 20 Mar 20 – Apr 3
Harvest May 29 May 29 – Jul 31

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

Month-by-Month Timeline

MonthActivities
January
February
March Transplant Outdoors
April Transplant Outdoors
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: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

249 days in Monterey County

Growing Tips for Thyme in Monterey County

Direct sow Thyme outdoors after March 13 in Monterey County when soil has warmed and frost danger has passed.

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 Monterey County, CA?

Monterey County is in Zone 9b with an average last frost of March 13. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.

What planting zone is Monterey County, CA?

Monterey County, California is in USDA Hardiness Zone 9b. The average last spring frost is March 13 and first fall frost is November 17.

When should I plant Thyme in Monterey County, CA?

In Monterey County, CA, plant Thyme after the last frost (around March 13) and before the first frost (around November 17). Best results when soil holds above 50°F.

What growing zone is Monterey County, CA for Thyme?

Monterey County sits in USDA Zone 9b. Thyme grows reliably in zones 4a through 9b, so it's a good fit here.

Can Thyme grow in Monterey County's climate?

Yes — Thyme grows well in Monterey County's temperate climate. Monterey County averages a 249-day frost-free season, with last frost around March 13 and first frost around November 17.

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Your Monterey County Garden Planner — Free

A 22-page printable planner built for Monterey 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 Monterey County, CA. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.