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When to Plant Tarragon in Jasper County, IL

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.

Jasper County, Illinois is in USDA Zone 6a. The average last spring frost is April 13 and the first fall frost is October 20, giving you a growing season of approximately 190 days.

At an elevation of 1,384 feet, Jasper County receives approximately 35 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91ยฐF, providing good warmth for Tarragon during the growing season.

Jasper County, IL (Zone 6a) Moderate season
190 days
Last Spring Frost April 13
190 growing days
First Fall Frost October 20

Jasper County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (50 days to spare)
Transplant: Apr 14 🍅 Harvest: Jun 16 – Aug 25
Recommended (50%) ✓ Fits season (50 days to spare)
Transplant: Apr 20 🍅 Harvest: Jun 22 – Aug 31
Safe Start (90%) ✓ Fits season (47 days to spare)
Transplant: May 4 🍅 Harvest: Jul 6 – Sep 14

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 459 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Tarragon needs ~1,369 GDD — county provides 3,467 GDD Excellent fit

Tarragon Planting Timeline โ€” Jasper County, IL

Tarragon Planting Calendar

Activity When Date Range
Transplant Outdoors April 20 Apr 20 โ€“ May 4
Harvest June 22 Jun 22 โ€“ Aug 31

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“90 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 6a

Growing Season

190 days

Growing Tips for Jasper 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

Level Up Your Garden

Frequently Asked Questions

When should I plant Tarragon in Jasper County, IL?

Jasper County is in Zone 6a with an average last frost of April 13. Plan your Tarragon planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jasper County, IL?

Jasper County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 13 and first fall frost is October 20.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jasper County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

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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 Jasper County, IL. Local conditions may vary. Last updated: April 2026.