When to Plant Thyme in Alameda County, CA
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.
Alameda County, California is in USDA Zone 9b. The average last spring frost is January 18 and the first fall frost is December 12, giving you a growing season of approximately 328 days.
At an elevation of 379 feet, Alameda County receives approximately 16.4 inches of rainfall annually with predominantly loam soil. Summer highs average 97°F, so Thyme may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Thyme successfully. Mulch heavily to conserve soil moisture.
Alameda County Soil Profile
Soil Type
Loam
Soil pH
6.3-7.7
Drainage
Well Drained
Plant Planting Risk Windows
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 Alameda County
How your county's soil matches Thyme's growing requirements.
Soil pH
Your soil pH (6.3–7.7) is within Thyme's preferred range (6.0–8.0).
Soil Texture
The loam soil in Alameda County is excellent for Thyme — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.0%). Annual compost additions will help Thyme.
How to Plant Thyme
Succession Planting Thyme
Sow every 8 weeks. Last sowing by Sep 13 to harvest before frost.
Plant Water Budget
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 | 1.3" | 3" | 0" | ✅ Rainfall sufficient |
| Feb | 1.3" | 3.6" | 0" | ✅ Rainfall sufficient |
| Mar | 1.3" | 2.6" | 0" | ✅ Rainfall sufficient |
| Apr | 1.3" | 1.2" | 0.1" | 💧 Light watering |
| May | 1.3" | 0.4" | 0.9" | 🚿 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" | 0.2" | 1.1" | 🚿 Regular watering |
| Oct | 1.3" | 0.6" | 0.7" | 🚿 Regular watering |
| Nov | 1.3" | 1.5" | 0" | ✅ Rainfall sufficient |
| Dec | 1.3" | 3.1" | 0" | ✅ Rainfall sufficient |
Water needs are for active growing months only (Jan–Dec in Alameda 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 Planting Timeline — Alameda County, CA
Thyme Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | January 25 | Jan 25 – Feb 8 |
| Harvest | April 5 | Apr 5 – Jun 7 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Transplant Outdoors |
| 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
0.3"/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
328 days in Alameda County
Growing Tips for Thyme in Alameda County
Direct sow Thyme outdoors after January 18 in Alameda County when soil has warmed and frost danger has passed.
With summer highs reaching 97°F in Alameda 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 →
Thyme in Other Locations
Frequently Asked Questions
When should I plant Thyme in Alameda County, CA?
Alameda County is in Zone 9b with an average last frost of January 18. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.
What planting zone is Alameda County, CA?
Alameda County, California is in USDA Hardiness Zone 9b. The average last spring frost is January 18 and first fall frost is December 12.
Plan Your Garden with Confidence
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