When to plant Basil in Mercer County, MO
In Zone 5b (Mercer County), direct-sow Basil between April 27 and May 18 for spring, after the April 20 last-frost mark.
When to Plant Basil in Mercer County, MO
Your June planting checklist for Mercer County, Missouri
June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Mercer County, Missouri.
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Get basil seeds going inside
Label every cell. You will absolutely forget which is which otherwise.
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Harvest basil as they ripen
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
Before July arrives, get these ready
- First harvests: basil
Basil is a fragrant warm-season herb essential to Italian and Thai cuisines. It comes in many varieties including sweet, Thai, purple, and lemon types.
Mercer County, Missouri is in USDA Zone 5b. The average last spring frost is April 20 and the first fall frost is October 14, giving you a growing season of approximately 177 days.
At an elevation of 523 feet, Mercer County receives approximately 41.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Basil during the growing season.
Mercer County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-6.8
Drainage
Well Drained
Basil 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 Mercer County
How your county's soil matches Basil's growing requirements.
Soil pH
Your soil pH (5.6–6.8) overlaps with Basil's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Mercer County is excellent for Basil — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Basil.
Organic Matter
Organic matter is moderate (2.9%). Annual compost additions will help Basil.
How to Plant Basil
Succession Planting Basil
Sow every 5.7 weeks. Last sowing by Jul 31 to harvest before frost.
Basil Water Budget
Monthly Watering Guide for Basil
Basil needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.
| Month | Basil Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 2" | 0" | ❄️ Dormant |
| Mar | — | 3.2" | 0" | ❄️ Dormant |
| Apr | 2.6" | 4.3" | 0" | ✅ Rainfall sufficient |
| May | 2.6" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jun | 2.6" | 5.1" | 0" | ✅ Rainfall sufficient |
| Jul | 2.6" | 4" | 0" | ✅ Rainfall sufficient |
| Aug | 2.6" | 4.4" | 0" | ✅ Rainfall sufficient |
| Sep | 2.6" | 3.6" | 0" | ✅ Rainfall sufficient |
| Oct | 2.6" | 3.2" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 2.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Mercer County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
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.
Basil Planting Timeline — Mercer County, MO
Basil Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 2 | Mar 2 – Mar 16 |
| Transplant Outdoors | May 4 | May 4 – May 18 |
| Direct Sow | April 27 | Apr 27 – May 18 |
| Harvest | June 29 | Jun 29 – Aug 31 |
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 | Harvest |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.6"/week · Natural rainfall sufficient
📅 Days to Maturity
50–75 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
177 days in Mercer County
Growing Tips for Basil in Mercer County
Direct sow Basil outdoors after April 20 in Mercer County when soil has warmed and frost danger has passed.
General growing tips
Start seeds indoors or direct sow after last frost. Pinch flower buds to extend leaf production. Harvest leaves from the top down, cutting just above a leaf pair.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Isolate 150 ft between varieties. Different basil species can cross.
Basil in Other Locations
Frequently Asked Questions
When should I plant Basil in Mercer County, MO?
Mercer County is in Zone 5b with an average last frost of April 20. Plan your Basil planting based on this frost date — see the calendar above for exact timing.
What planting zone is Mercer County, MO?
Mercer County, Missouri is in USDA Hardiness Zone 5b. The average last spring frost is April 20 and first fall frost is October 14.
When should I plant Basil in Mercer County, MO?
In Mercer County, MO, plant Basil after the last frost (around April 20) and before the first frost (around October 14). Best results when soil holds above 50°F.
What growing zone is Mercer County, MO for Basil?
Mercer County sits in USDA Zone 5b. Basil grows reliably in zones 4a through 11b, so it's a good fit here.
Can Basil grow in Mercer County's climate?
Yes — Basil grows well in Mercer County's temperate climate. Mercer County averages a 177-day frost-free season, with last frost around April 20 and first frost around October 14.
Your Mercer County Garden Planner — Free
A 22-page printable planner built for Mercer 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.