When to Plant Thyme in Yolo 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.
Yolo County, California is in USDA Zone 9a. The average last spring frost is February 9 and the first fall frost is December 3, giving you a growing season of approximately 297 days.
At an elevation of 163 feet, Yolo County receives approximately 27.7 inches of rainfall annually with predominantly loam soil. Summer highs average 95°F, so Thyme may need afternoon shade and extra watering during peak heat.
Yolo County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.8
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 Yolo County
How your county's soil matches Thyme's growing requirements.
Soil pH
Your soil pH (6.7–7.8) is within Thyme's preferred range (6.0–8.0).
Soil Texture
The loam soil in Yolo County is excellent for Thyme — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.4%). Annual compost additions will help Thyme.
How to Plant Thyme
Succession Planting Thyme
Sow every 8 weeks. Last sowing by Sep 04 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 | — | 6" | 0" | ❄️ Dormant |
| Feb | 1.3" | 5.4" | 0" | ✅ Rainfall sufficient |
| Mar | 1.3" | 4" | 0" | ✅ Rainfall sufficient |
| Apr | 1.3" | 2.3" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 0.8" | 0.5" | 💧 Light 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" | 0.3" | 1" | 🚿 Regular watering |
| Oct | 1.3" | 1.1" | 0.2" | 💧 Light watering |
| Nov | 1.3" | 2.6" | 0" | ✅ Rainfall sufficient |
| Dec | 1.3" | 5.1" | 0" | ✅ Rainfall sufficient |
Water needs are for active growing months only (Feb–Dec in Yolo 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 — Yolo County, CA
Thyme Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | February 16 | Feb 16 – Mar 2 |
| Harvest | April 27 | Apr 27 – Jun 29 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Transplant Outdoors |
| March | Transplant Outdoors |
| April | Harvest |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.3"/week · Natural rainfall sufficient
📅 Days to Maturity
70–90 days
🧪 Soil pH
Needs 6–8 · Your soil: ideal
🗺️ USDA Zone
Zone 9a
📆 Growing Season
297 days in Yolo County
Growing Tips for Thyme in Yolo County
Direct sow Thyme outdoors after February 09 in Yolo 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 →
Thyme in Other Locations
Frequently Asked Questions
When should I plant Thyme in Yolo County, CA?
Yolo County is in Zone 9a with an average last frost of February 9. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.
What planting zone is Yolo County, CA?
Yolo County, California is in USDA Hardiness Zone 9a. The average last spring frost is February 9 and first fall frost is December 3.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Yolo County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.
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