When to Plant Thai Basil in Des Moines County, IA
May in Des Moines County, Iowa — your action list
Your Des Moines County, Iowa garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.
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Move thai basil into the garden
Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.
To set up a strong June, finish these tasks
- Starting indoors: thai basil
- First harvests: 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.
Des Moines County, Iowa is in USDA Zone 6a. The average last spring frost is April 17 and the first fall frost is October 16, giving you a growing season of approximately 182 days.
At an elevation of 606 feet, Des Moines County receives approximately 38.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Thai Basil during the growing season.
Des Moines County Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-6.7
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 Des Moines County
How your county's soil matches Thai Basil's growing requirements.
Soil pH
Your soil pH (6.2–6.7) is within Thai Basil's preferred range (6.0–7.0).
Soil Texture
The silt loam soil in Des Moines County is excellent for Thai Basil — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Thai Basil.
Organic Matter
Organic matter is moderate (4.0%). Annual compost additions will help Thai Basil.
How to Plant Thai Basil
Succession Planting Thai Basil
Sow every 5.7 weeks. Last sowing by Aug 02 to harvest before frost.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
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 | — | 1.8" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.3" | 1" | 💧 Light watering |
| May | 4.3" | 4" | 0.3" | 💧 Light watering |
| Jun | 4.3" | 5.4" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 4.6" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Oct | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| Nov | — | 2.9" | 0" | ❄️ Dormant |
| Dec | — | 2.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Des Moines 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 — Des Moines County, IA
Thai Basil Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 27 | Feb 27 – Mar 13 |
| Transplant Outdoors | May 1 | May 1 – May 15 |
| Direct Sow | April 24 | Apr 24 – May 15 |
| Harvest | June 26 | Jun 26 – Aug 28 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
50–75 days
🧪 Soil pH
Needs 6–7 · Your soil: ideal
🗺️ USDA Zone
Zone 6a
📆 Growing Season
182 days in Des Moines County
Growing Tips for Thai Basil in Des Moines County
Direct sow Thai Basil outdoors after April 17 in Des Moines 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 Des Moines County, IA?
Des Moines County is in Zone 6a with an average last frost of April 17. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.
What planting zone is Des Moines County, IA?
Des Moines County, Iowa is in USDA Hardiness Zone 6a. The average last spring frost is April 17 and first fall frost is October 16.
Your Des Moines County Garden Planner — Free
A 24-page printable planner built for Des Moines 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.