When to plant Tarragon in Marshall County, IL
Plant Tarragon in Marshall County, between April 28 and May 12 — the only viable window. Zone 5b's short season (175 frost-free days) rules out a fall crop.
When to Plant Tarragon in Marshall County, IL
Your July game plan for Marshall County, Illinois
We've pulled the most time-sensitive tasks for Marshall County, Illinois this July and put them front and centre. Tackle them in order.
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It's harvest week for tarragon
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
August prep starts now
- First harvests: tarragon
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.
Marshall County, Illinois is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 13, giving you a growing season of approximately 175 days.
At an elevation of 1,177 feet, Marshall County receives approximately 30.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Tarragon to ensure they mature before fall.
Marshall County Soil Profile
Soil Type
Silt Loam
Soil pH
6-6.8
Drainage
Well Drained
Tarragon Planting Risk Windows
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 Marshall County
How your county's soil matches Tarragon's growing requirements.
Soil pH
Your soil pH (6.0–6.8) is within Tarragon's preferred range (6.0–7.5).
Soil Texture
The silt loam soil in Marshall County is excellent for Tarragon — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.2%) — Tarragon will thrive.
How to Plant Tarragon
Succession Planting Tarragon
Sow every 6.9 weeks. Last sowing by Jul 15 to harvest before frost.
Tarragon Water Budget
Water stress score is 6/10 — 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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 1.7" | 2.8" | 0" | ✅ Rainfall sufficient |
| May | 1.7" | 3.4" | 0" | ✅ Rainfall sufficient |
| Jun | 1.7" | 4" | 0" | ✅ Rainfall sufficient |
| Jul | 1.7" | 3" | 0" | ✅ Rainfall sufficient |
| Aug | 1.7" | 3.4" | 0" | ✅ Rainfall sufficient |
| Sep | 1.7" | 2.7" | 0" | ✅ Rainfall sufficient |
| Oct | 1.7" | 2.5" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2" | 0" | ❄️ Dormant |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Marshall 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 Planting Timeline — Marshall County, IL
Tarragon Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 28 | Apr 28 – May 12 |
| Harvest | June 30 | Jun 30 – Sep 8 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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: ideal
🗺️ USDA Zone
Zone 5b
📆 Growing Season
175 days in Marshall County
Growing Tips for Tarragon in Marshall County
Direct sow Tarragon outdoors after April 21 in Marshall 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 →
Tarragon in Other Locations
Frequently Asked Questions
When should I plant Tarragon in Marshall County, IL?
Marshall County is in Zone 5b with an average last frost of April 21. Plan your Tarragon planting based on this frost date — see the calendar above for exact timing.
What planting zone is Marshall County, IL?
Marshall County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 21 and first fall frost is October 13.
When should I plant Tarragon in Marshall County, IL?
In Marshall County, IL, plant Tarragon after the last frost (around April 21) and before the first frost (around October 13). Best results when soil holds above 50°F.
What growing zone is Marshall County, IL for Tarragon?
Marshall County sits in USDA Zone 5b. Tarragon grows reliably in zones 4a through 9b, so it's a good fit here.
Can Tarragon grow in Marshall County's climate?
Yes — Tarragon grows well in Marshall County's temperate climate. Marshall County averages a 175-day frost-free season, with last frost around April 21 and first frost around October 13.
Your Marshall County Garden Planner — Free
A 22-page printable planner built for Marshall County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.