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When to Plant Tarragon in Shoshone County, ID

Shoshone County, Idaho Zone 6b May

Shoshone County, Idaho gardeners: here's your May plan

May is a pivotal month for Shoshone County, Idaho gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 10
Avg. first frost September 26
Soil temp (4") 41°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Harden off and plant tarragon

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

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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.

Shoshone County, Idaho is in USDA Zone 6b. The average last spring frost is May 10 and the first fall frost is September 26, giving you a growing season of approximately 139 days.

At an elevation of 6,353 feet, Shoshone County receives approximately 14.1 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Tarragon to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Tarragon successfully. Mulch heavily to conserve soil moisture.

Shoshone County, ID (Zone 6b) Short season
139 days
Last Spring Frost May 10
139 growing days
First Fall Frost September 26
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Shoshone County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 10 🍅 Harvest: Jul 12 – Sep 20
Recommended (50%) ✗ May not fit
Transplant: May 17 🍅 Harvest: Jul 19 – Sep 27
Safe Start (90%) ✓ Fits season (2 days to spare)
Transplant: Jun 11 🍅 Harvest: Aug 13 – Oct 22

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 Shoshone County

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

Soil pH

Your soil pH (6.6–7.7) overlaps with Tarragon's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Tarragon.

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Tarragon.

How to Plant Tarragon

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

Succession Planting Tarragon

2
successive plantings in your 139-day season

Sow every 6.9 weeks. Last sowing by Jun 28 to harvest before frost.

Plant Water Budget

Plant needs
0.4″/week
Rainfall provides
0.4″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 139 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 1.7" 1.9" 0" ✅ Rainfall sufficient
Jun 1.7" 0.9" 0.8" 💧 Light watering
Jul 1.7" 1.2" 0.5" 💧 Light watering
Aug 1.7" 1.5" 0.2" 💧 Light watering
Sep 1.7" 1.3" 0.4" 💧 Light watering
Oct 1.2" 0" ❄️ Dormant
Nov 0.9" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Shoshone 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 ~975 GDD — county provides 1,807 GDD Excellent fit

Tarragon Planting Timeline — Shoshone County, ID

Tarragon Planting Calendar

Activity When Date Range
Transplant Outdoors May 17 May 17 – May 31
Harvest July 19 Jul 19 – Sep 27

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July Harvest
August Harvest
September Harvest
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: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

139 days in Shoshone County

Growing Tips for Tarragon in Shoshone County

Direct sow Tarragon outdoors after May 10 in Shoshone 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 Shoshone County, ID?

Shoshone County is in Zone 6b with an average last frost of May 10. Plan your Tarragon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Shoshone County, ID?

Shoshone County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 10 and first fall frost is September 26.

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Your Shoshone County Garden Planner — Free

A 24-page printable planner built for Shoshone County (Zone 6b). 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 Shoshone County, ID. 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.