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When to plant Tarragon in Gem County, ID

Plant Tarragon in Gem County during the brief May 16–May 30 window. With 145 frost-free days, fall plantings can't mature before October 1.

When to Plant Tarragon in Gem County, ID

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.

Gem County, Idaho is in USDA Zone 7a. The average last spring frost is May 9 and the first fall frost is October 1, giving you a growing season of approximately 145 days.

At an elevation of 6,100 feet, Gem County receives approximately 16 inches of rainfall annually with predominantly loam soil. Summer highs average 87°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.

Gem County, ID (Zone 7a) Short season
145 days
Last Spring Frost May 9
145 growing days
First Fall Frost October 1

Gem County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.7

Drainage

Well Drained

Monthly Watering Guide for Tarragon

Tarragon needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Tarragon Needs Rainfall You Supplement Action
Jan 1.2" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.6" 0" ❄️ Dormant
May 4.3" 1.7" 2.6" 🚿 Regular watering
Jun 4.3" 1.2" 3.1" 🚿 Regular watering
Jul 4.3" 1.5" 2.8" 🚿 Regular watering
Aug 4.3" 1.5" 2.8" 🚿 Regular watering
Sep 4.3" 1.4" 2.9" 🚿 Regular watering
Oct 4.3" 1.5" 2.8" 🚿 Regular watering
Nov 1.1" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Gem County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Tarragon Planting Timeline — Gem County, ID

Tarragon Planting Calendar

Activity When Date Range
Transplant Outdoors May 16 May 16 – May 30
Harvest July 18 Jul 18 – Sep 26

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 7a

📆 Growing Season

145 days in Gem County

Growing Tips for Gem County

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 Gem County, ID?

Gem County is in Zone 7a with an average last frost of May 9. Plan your Tarragon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Gem County, ID?

Gem County, Idaho is in USDA Hardiness Zone 7a. The average last spring frost is May 9 and first fall frost is October 1.

When should I plant Tarragon in Gem County, ID?

In Gem County, ID, plant Tarragon after the last frost (around May 9) and before the first frost (around October 1). Best results when soil holds above 50°F.

What growing zone is Gem County, ID for Tarragon?

Gem County sits in USDA Zone 7a. Tarragon grows reliably in zones 4a through 9b, so it's a good fit here.

Can Tarragon grow in Gem County's climate?

Yes — Tarragon grows well in Gem County's temperate climate. Gem County averages a 145-day frost-free season, with last frost around May 9 and first frost around October 1.

🌱

Your Gem County Garden Planner — Free

A 22-page printable planner built for Gem County (Zone 7a). 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 Gem County, ID. Local conditions may vary. Last updated: June 2026.

Sources & credits

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