When to plant Thyme in Sullivan, IL
In Sullivan, Thyme is a single-season spring crop — there's no second fall window. Plant April 21–May 5 for an 70–90-day harvest, finishing well before the October 17 first frost.
When to Plant Thyme in Sullivan, IL
Your July planting checklist for Moultrie County, Illinois
July is a pivotal month for Moultrie County, Illinois gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Bring in the thyme
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
Get ahead of August
- First harvests: thyme
Thyme is a low-growing perennial herb with tiny, aromatic leaves and a warm, earthy flavor. It is one of the most versatile culinary and medicinal herbs.
Sullivan, Illinois is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.
At an elevation of 596 feet, Moultrie County receives approximately 30 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Thyme to ensure they mature before fall.
Sullivan Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-7.2
Drainage
Well Drained
Thyme 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 Sullivan
How your county's soil matches Thyme's growing requirements.
Soil pH
Your soil pH (5.8–7.2) overlaps with Thyme's range (6.0–8.0), though not a perfect match.
Soil Texture
The silt loam soil in Moultrie County is excellent for Thyme — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.2%) — Thyme will thrive.
How to Plant Thyme
Succession Planting Thyme
Sow every 8 weeks. Last sowing by Jul 19 to harvest before frost.
Thyme Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Thyme
Thyme needs approximately 0.3 inches of water per week (1.3" per month). Here's how your county's rainfall compares month by month.
| Month | Thyme Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.1" | 0" | ❄️ Dormant |
| Feb | — | 1.2" | 0" | ❄️ Dormant |
| Mar | — | 2.2" | 0" | ❄️ Dormant |
| Apr | 1.3" | 2.7" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 3" | 0" | ✅ Rainfall sufficient |
| Jun | 1.3" | 4.2" | 0" | ✅ Rainfall sufficient |
| Jul | 1.3" | 3.7" | 0" | ✅ Rainfall sufficient |
| Aug | 1.3" | 3" | 0" | ✅ Rainfall sufficient |
| Sep | 1.3" | 2.7" | 0" | ✅ Rainfall sufficient |
| Oct | 1.3" | 2.4" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.1" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Moultrie County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Thyme 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.
Thyme Planting Timeline — Sullivan, IL
Thyme Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 21 | Apr 21 – May 5 |
| Harvest | June 30 | Jun 30 – Sep 1 |
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
0.3"/week · Natural rainfall sufficient
📅 Days to Maturity
70–90 days
🧪 Soil pH
Needs 6–8 · Your soil: acceptable
🗺️ USDA Zone
Zone 6a
📆 Growing Season
186 days in Moultrie County
Growing Tips for Thyme in Sullivan
Direct sow Thyme outdoors after April 14 in Moultrie County when soil has warmed and frost danger has passed.
General growing tips
Start from seed, cuttings, or divisions. Plant in well-drained, lean soil. Prune lightly after flowering. Replace plants every 3-4 years when they become woody.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Thyme in Other Locations
When should I plant Thyme in Sullivan, IL?
In Sullivan, IL, plant Thyme after the last frost (around April 14) and before the first frost (around October 17). Best results when soil holds above 50°F.
What growing zone is Sullivan, IL for Thyme?
Sullivan sits in USDA Zone 6a. Thyme grows reliably in zones 4a through 9b, so it's a good fit here.
Can Thyme grow in Sullivan's climate?
Yes — Thyme grows well in Sullivan's temperate climate. Sullivan averages a 186-day frost-free season, with last frost around April 14 and first frost around October 17.
Your Moultrie County Garden Planner — Free
A 22-page printable planner built for Moultrie County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.