When to plant Thai Basil in Boone County, IL
Spring Thai Basil in Boone County goes in April 30–May 21, once nighttime temps stop dipping near freezing.
When to Plant Thai Basil in Boone County, IL
Thai basil has a distinctive anise-licorice flavor with sturdy purple stems and small leaves. It is essential in Thai, Vietnamese, and other Southeast Asian cuisines.
Boone County, Illinois is in USDA Zone 5b. The average last spring frost is April 23 and the first fall frost is October 16, giving you a growing season of approximately 176 days.
At an elevation of 512 feet, Boone County receives approximately 39.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Thai Basil to ensure they mature before fall.
Boone County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Thai Basil Planting Timeline — Boone County, IL
Thai Basil Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 5 | Mar 5 – Mar 19 |
| Transplant Outdoors | May 7 | May 7 – May 21 |
| Direct Sow | April 30 | Apr 30 – May 21 |
| Harvest | July 2 | Jul 2 – Sep 3 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Direct Sow |
| May | Transplant Outdoors Direct Sow |
| 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
50–75 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 5b
📆 Growing Season
176 days in Boone County
Growing Tips for Boone County
Start seeds indoors or direct sow after last frost. Thai basil holds up better to heat in cooking than sweet basil. Pinch flowers to prolong leaf production.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Thai Basil in Other Locations
Frequently Asked Questions
When should I plant Thai Basil in Boone County, IL?
Boone County is in Zone 5b with an average last frost of April 23. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.
What planting zone is Boone County, IL?
Boone County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 23 and first fall frost is October 16.
When should I plant Thai Basil in Boone County, IL?
In Boone County, IL, plant Thai Basil after the last frost (around April 23) and before the first frost (around October 16). Best results when soil holds above 50°F.
What growing zone is Boone County, IL for Thai Basil?
Boone County sits in USDA Zone 5b. Thai Basil grows reliably in zones 4a through 11b, so it's a good fit here.
Can Thai Basil grow in Boone County's climate?
Yes — Thai Basil grows well in Boone County's temperate climate. Boone County averages a 176-day frost-free season, with last frost around April 23 and first frost around October 16.
Your Boone County Garden Planner — Free
A 22-page printable planner built for Boone 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.