When to plant Tarragon in Sonoma County County,
Sonoma County County sits in cold Zone 9b. Plant Tarragon March 5–March 19 for the single annual harvest; the November 26 first frost closes the window.
When to Plant Tarragon in Sonoma County, CA
What to do in June
If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.
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It's harvest week for tarragon
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
Coming up in July — start thinking about
- First harvests: tarragon
French tarragon is a perennial herb with slender leaves and a distinctive anise-like flavor essential in French cooking. It does not produce viable seed and must be propagated vegetatively.
Sonoma County, California is in USDA Zone 9b. The average last spring frost is February 26 and the first fall frost is November 26, giving you a growing season of approximately 273 days.
At an elevation of 91 feet, Sonoma County receives approximately 31.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 90°F, providing good warmth for Tarragon during the growing season. Sandy soil warms quickly in spring — great for early planting — but Tarragon will need more frequent watering and organic matter to retain nutrients.
Sonoma County Soil Profile
Soil Type
Sandy Loam
Soil pH
5.9-7
Drainage
Well Drained
Tarragon 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 Sonoma County
How your county's soil matches Tarragon's growing requirements.
Soil pH
Your soil pH (5.9–7.0) overlaps with Tarragon's range (6.0–7.5), though not a perfect match.
Soil Texture
Sandy soil in Sonoma County warms quickly in spring but drains fast. Tarragon will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Drainage is adequate for Tarragon.
Organic Matter
Organic matter is moderate (2.5%). Annual compost additions will help Tarragon.
How to Plant Tarragon
Succession Planting Tarragon
Sow every 6.9 weeks. Last sowing by Aug 28 to harvest before frost.
Tarragon Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Tarragon
Tarragon needs approximately 0.4 inches of water per week (1.7" per month). Here's how your county's rainfall compares month by month.
| Month | Tarragon Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 6.2" | 0" | ❄️ Dormant |
| Feb | 1.7" | 6.8" | 0" | ✅ Rainfall sufficient |
| Mar | 1.7" | 5.2" | 0" | ✅ Rainfall sufficient |
| Apr | 1.7" | 2.3" | 0" | ✅ Rainfall sufficient |
| May | 1.7" | 0.8" | 0.9" | 🚿 Regular watering |
| Jun | 1.7" | 0.1" | 1.6" | 🚿 Regular watering |
| Jul | 1.7" | 0" | 1.7" | 🚿 Regular watering |
| Aug | 1.7" | 0" | 1.7" | 🚿 Regular watering |
| Sep | 1.7" | 0.4" | 1.3" | 🚿 Regular watering |
| Oct | 1.7" | 1.3" | 0.4" | 💧 Light watering |
| Nov | 1.7" | 2.7" | 0" | ✅ Rainfall sufficient |
| Dec | — | 5.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Feb–Nov in Sonoma County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Tarragon 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.
Tarragon Planting Timeline — Sonoma County, CA
Tarragon Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | March 5 | Mar 5 – Mar 19 |
| Harvest | May 7 | May 7 – Jul 16 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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
0.4"/week · Only during dry spells
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 9b
📆 Growing Season
273 days in Sonoma County
Growing Tips for Tarragon in Sonoma County
Direct sow Tarragon outdoors after February 26 in Sonoma County when soil has warmed and frost danger has passed.
Sandy soil in Sonoma County dries quickly — mulch Tarragon with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
Common pests for Tarragon in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
Purchase plants or divisions as French tarragon does not grow true from seed. Plant in well-drained soil. Divide every 3-4 years to maintain vigor. Harvest tips regularly for best flavor.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Tarragon in Other Locations
Frequently Asked Questions
When should I plant Tarragon in Sonoma County, CA?
Sonoma County is in Zone 9b with an average last frost of February 26. Plan your Tarragon planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sonoma County, CA?
Sonoma County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 26 and first fall frost is November 26.
When should I plant Tarragon in Sonoma County County, ?
In Sonoma County County, , plant Tarragon after the last frost (around February 26) and before the first frost (around November 26). Best results when soil holds above 50°F.
What growing zone is Sonoma County County, for Tarragon?
Sonoma County County sits in USDA Zone 9b. Tarragon grows reliably in zones 4a through 9b, so it's a good fit here.
Can Tarragon grow in Sonoma County County's climate?
Yes — Tarragon grows well in Sonoma County County's temperate climate. Sonoma County County averages a 274-day frost-free season, with last frost around February 26 and first frost around November 26.
Your Sonoma County Garden Planner — Free
A 22-page printable planner built for Sonoma 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.