When to Plant Thai Basil in Richland County, WI
May in Richland County, Wisconsin — your action list
If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.
-
Set out thai basil seedlings
Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.
-
Sow thai basil where they'll grow
Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.
Looking ahead to June
- Starting indoors: thai basil
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.
Richland County, Wisconsin is in USDA Zone 5a. The average last spring frost is May 5 and the first fall frost is October 5, giving you a growing season of approximately 153 days.
At an elevation of 1,098 feet, Richland County receives approximately 38.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Thai Basil during the growing season.
Richland County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-6.9
Drainage
Well Drained
Plant 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 Richland County
How your county's soil matches Thai Basil's growing requirements.
Soil pH
Your soil pH (5.8–6.9) overlaps with Thai Basil's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Richland County is excellent for Thai Basil — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.9%) — Thai Basil will thrive.
How to Plant Thai Basil
Succession Planting Thai Basil
Sow every 5.7 weeks. Last sowing by Jul 22 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Thai Basil
Thai Basil needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Thai Basil Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.9" | 0" | ❄️ Dormant |
| Mar | — | 2.8" | 0" | ❄️ Dormant |
| Apr | — | 3.8" | 0" | ❄️ Dormant |
| May | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Jun | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Sep | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Oct | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Nov | — | 2.9" | 0" | ❄️ Dormant |
| Dec | — | 2.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Richland County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Thai Basil 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.
Thai Basil Planting Timeline — Richland County, WI
Thai Basil Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 17 | Mar 17 – Mar 31 |
| Transplant Outdoors | May 19 | May 19 – Jun 2 |
| Direct Sow | May 12 | May 12 – Jun 2 |
| Harvest | July 14 | Jul 14 – Sep 15 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
50–75 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 5a
📆 Growing Season
153 days in Richland County
Growing Tips for Thai Basil in Richland County
Direct sow Thai Basil outdoors after May 05 in Richland County when soil has warmed and frost danger has passed.
General growing tips
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 Richland County, WI?
Richland County is in Zone 5a with an average last frost of May 5. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.
What planting zone is Richland County, WI?
Richland County, Wisconsin is in USDA Hardiness Zone 5a. The average last spring frost is May 5 and first fall frost is October 5.
Your Richland County Garden Planner — Free
A 24-page printable planner built for Richland County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.