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When to Plant Tarragon in Mason County, WA

Mason County, Washington Zone 8b May

Your May planting checklist for Mason County, Washington

Your Mason County, Washington garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 18
Avg. first frost October 29
Soil temp (4") 68°F
Watering High
Pest pressure High
Daylight 14.9 hrs
A few tasks this May that'll pay off in June
  • 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.

Mason County, Washington is in USDA Zone 8b. The average last spring frost is April 18 and the first fall frost is October 29, giving you a growing season of approximately 194 days.

At an elevation of 230 feet, Mason County receives approximately 36.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Tarragon during the growing season.

Mason County, WA (Zone 8b) Moderate season
194 days
Last Spring Frost April 18
194 growing days
First Fall Frost October 29

Mason County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (54 days to spare)
Transplant: Apr 12 🍅 Harvest: Jun 14 – Aug 23
Recommended (50%) ✓ Fits season (54 days to spare)
Transplant: Apr 25 🍅 Harvest: Jun 27 – Sep 5
Safe Start (90%) ✓ Fits season (67 days to spare)
Transplant: May 16 🍅 Harvest: Jul 18 – Sep 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 Mason County

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

Soil pH

Your soil pH (5.4–6.7) overlaps with Tarragon's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.3%) — Tarragon will thrive.

How to Plant Tarragon

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

Succession Planting Tarragon

3
successive plantings in your 194-day season

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

Plant Water Budget

Plant needs
0.4″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 5" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 4.1" 0" ❄️ Dormant
Apr 1.7" 2.9" 0" ✅ Rainfall sufficient
May 1.7" 1.8" 0" ✅ Rainfall sufficient
Jun 1.7" 1.5" 0.2" 💧 Light watering
Jul 1.7" 0.6" 1.1" 🚿 Regular watering
Aug 1.7" 0.7" 1" 🚿 Regular watering
Sep 1.7" 1.3" 0.4" 💧 Light watering
Oct 1.7" 3.2" 0" ✅ Rainfall sufficient
Nov 6.5" 0" ❄️ Dormant
Dec 5.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Mason 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 ~1,031 GDD — county provides 2,667 GDD Excellent fit

Tarragon Planting Timeline — Mason County, WA

Tarragon Planting Calendar

Activity When Date Range
Transplant Outdoors April 25 Apr 25 – May 9
Harvest June 27 Jun 27 – Sep 5

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.4"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

194 days in Mason County

Growing Tips for Tarragon in Mason County

Direct sow Tarragon outdoors after April 18 in Mason 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 Mason County, WA?

Mason County is in Zone 8b with an average last frost of April 18. Plan your Tarragon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mason County, WA?

Mason County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 18 and first fall frost is October 29.

🌱

Your Mason County Garden Planner — Free

A 24-page printable planner built for Mason County (Zone 8b). 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 Mason County, WA. 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.