When to Plant Rosemary in Solano County, CA
Top priorities for Solano County, California gardeners in May
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.
-
Collect rosemary 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: rosemary
Rosemary is an aromatic evergreen shrub with needle-like leaves and a piney, citrus flavor. It is a Mediterranean herb that thrives in warm, dry conditions.
Solano County, California is in USDA Zone 9b. 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 376 feet, Solano County receives approximately 40.4 inches of rainfall annually with predominantly loam soil. Summer highs average 95°F, so Rosemary may need afternoon shade and extra watering during peak heat.
Solano County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.3
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 Solano County
How your county's soil matches Rosemary's growing requirements.
Soil pH
Your soil pH (6.8–7.3) is within Rosemary's preferred range (6.0–7.5).
Soil Texture
The loam soil in Solano County is excellent for Rosemary — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Rosemary.
Organic Matter
Organic matter is moderate (2.6%). Annual compost additions will help Rosemary.
How to Plant Rosemary
Succession Planting Rosemary
Sow every 9.1 weeks. Last sowing by Jun 06 to harvest before frost.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Rosemary
Rosemary 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 | Rosemary Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 8.9" | 0" | ❄️ Dormant |
| Feb | 1.3" | 8.4" | 0" | ✅ Rainfall sufficient |
| Mar | 1.3" | 6.6" | 0" | ✅ Rainfall sufficient |
| Apr | 1.3" | 2.7" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 1" | 0.3" | 💧 Light watering |
| Jun | 1.3" | 0.2" | 1.1" | 🚿 Regular watering |
| Jul | 1.3" | 0" | 1.3" | 🚿 Regular watering |
| Aug | 1.3" | 0" | 1.3" | 🚿 Regular watering |
| Sep | 1.3" | 0.4" | 0.9" | 🚿 Regular watering |
| Oct | 1.3" | 1.9" | 0" | ✅ Rainfall sufficient |
| Nov | 1.3" | 3.3" | 0" | ✅ Rainfall sufficient |
| Dec | 1.3" | 7.1" | 0" | ✅ Rainfall sufficient |
Water needs are for active growing months only (Feb–Dec in Solano County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Rosemary 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.
Rosemary Planting Timeline — Solano County, CA
Rosemary Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | February 16 | Feb 16 – Mar 2 |
| Harvest | May 11 | May 11 – Sep 28 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Transplant Outdoors |
| March | Transplant Outdoors |
| April | — |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.3"/week · Natural rainfall sufficient
📅 Days to Maturity
80–180 days
🧪 Soil pH
Needs 6–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 9b
📆 Growing Season
297 days in Solano County
Growing Tips for Rosemary in Solano County
Direct sow Rosemary outdoors after February 09 in Solano County when soil has warmed and frost danger has passed.
General growing tips
Grow in well-drained soil and avoid overwatering. In cold climates, grow in containers and bring indoors for winter. Propagate from stem cuttings for faster results than seed.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Rosemary in Other Locations
Frequently Asked Questions
When should I plant Rosemary in Solano County, CA?
Solano County is in Zone 9b with an average last frost of February 9. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.
What planting zone is Solano County, CA?
Solano County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 9 and first fall frost is December 3.
Your Solano County Garden Planner — Free
A 24-page printable planner built for Solano 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.