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When to Plant Tarragon in San Benito County, CA

San Benito County, California Zone 9b May

May to-do list for San Benito County, California

Each item below is timed to San Benito County, California's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost February 21
Avg. first frost November 29
Soil temp (4") 76°F
Watering Critical
Pest pressure High
Daylight 14 hrs
  1. Bring in the tarragon

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

June prep starts now
  • First harvests: tarragon

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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.

San Benito County, California is in USDA Zone 9b. The average last spring frost is February 21 and the first fall frost is November 29, giving you a growing season of approximately 281 days.

At an elevation of 149 feet, San Benito County receives approximately 13 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Tarragon during the growing season. With low rainfall, drip irrigation is essential for growing Tarragon successfully. Mulch heavily to conserve soil moisture.

San Benito County, CA (Zone 9b) Year-round
281 days
Last Spring Frost February 21
281 growing days
First Fall Frost November 29
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San Benito County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (150 days to spare)
Transplant: Feb 12 🍅 Harvest: Apr 16 – Jun 25
Recommended (50%) ✓ Fits season (141 days to spare)
Transplant: Feb 28 🍅 Harvest: May 2 – Jul 11
Safe Start (90%) ✓ Fits season (117 days to spare)
Transplant: Apr 15 🍅 Harvest: Jun 17 – Aug 26

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 San Benito County

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

Soil pH

Your soil pH (6.5–7.4) is within Tarragon's preferred range (6.0–7.5).

Soil Texture

The loam soil in San Benito County is excellent for Tarragon — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

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

How to Plant Tarragon

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

Succession Planting Tarragon

5
successive plantings in your 281-day season

Sow every 6.9 weeks. Last sowing by Aug 31 to harvest before frost.

Plant Water Budget

Plant needs
0.4″/week
Rainfall provides
0.2″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 622 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 2.5" 0" ❄️ Dormant
Feb 1.7" 2.6" 0" ✅ Rainfall sufficient
Mar 1.7" 2.2" 0" ✅ Rainfall sufficient
Apr 1.7" 1.1" 0.6" 💧 Light watering
May 1.7" 0.3" 1.4" 🚿 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" 0.1" 1.6" 🚿 Regular watering
Oct 1.7" 0.5" 1.2" 🚿 Regular watering
Nov 1.7" 1.3" 0.4" 💧 Light watering
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in San Benito 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 needs ~1,538 GDD — county provides 5,781 GDD Excellent fit

Tarragon Planting Timeline — San Benito County, CA

Tarragon Planting Calendar

Activity When Date Range
Transplant Outdoors February 28 Feb 28 – Mar 14
Harvest May 2 May 2 – Jul 11

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

Month-by-Month Timeline

MonthActivities
January
February Transplant Outdoors
March Transplant Outdoors
April
May Harvest
June Harvest
July Harvest
August
September
October
November
December
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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: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

281 days in San Benito County

Growing Tips for Tarragon in San Benito County

Direct sow Tarragon outdoors after February 21 in San Benito County when soil has warmed and frost danger has passed.

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 →

Frequently Asked Questions

When should I plant Tarragon in San Benito County, CA?

San Benito County is in Zone 9b with an average last frost of February 21. Plan your Tarragon planting based on this frost date — see the calendar above for exact timing.

What planting zone is San Benito County, CA?

San Benito County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 21 and first fall frost is November 29.

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Your San Benito County Garden Planner — Free

A 24-page printable planner built for San Benito 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 San Benito County, CA. Local conditions may vary. Last updated: May 2026.

Sources & credits

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