When to Plant Basil in Missouri
Published: April 21, 2026
Missouri gardeners in Zone 6b have a 33-week growing season for basil (March 22 to November 10). The moderate climate supports a full warm-season crop plus a single main harvest. This guide gives exact dates for Missouri based on your local frost calendar.
Basil Planting Dates for Missouri
| Start seeds indoors | February 8–15 |
| Last frost (average) | March 22 |
| Transplant outdoors | April 5–15 |
| Direct sow outdoors | April 5–15 |
| Expect first harvest | May 5 – June 4 |
| First fall frost (average) | November 10 |
Dates above assume Zone 6b, the most common zone in Missouri. Gardeners in cooler St. Louis (Zone 6b) plant 1–2 weeks later; warmer Kansas City (Zone 6a) can plant 1–2 weeks earlier.
Growing Basil in Missouri's Climate
Missouri's moderate Zone 6b climate is well-suited to basil with minimal special accommodation. The standard transplant calendar works as written, and harvest windows line up with what seed packets recommend without adjustment.
Succession planting extends your basil harvest significantly in Missouri. A second planting 3 to 4 weeks after the first gives you a backup in case of pest pressure and extends the total harvest window into early fall.
Common basil pests to watch for in Missouri include Aphids and Spider Mite. The first line of defense is companion planting: Tomato and Pepper planted nearby discourage several of these pests by confusing host-plant identification or repelling adults before they can lay eggs. Weekly garden walks in the early morning catch problems when they're still manageable.
Basil Garden Calendar for Missouri
| Month | Task | Notes |
|---|---|---|
| January | — | Dormant season |
| February | Start seeds indoors | Use grow lights; warm soil to 70–75°F for best germination |
| March | Harden off seedlings | Set seedlings outdoors 1–2 hours daily, increasing gradually |
| April | Transplant outdoors | Soil temp must be 60°F+; nighttime lows above 50°F |
| May ← | First harvest window opens | Basil begins producing 30–60 days after transplant |
| June | Peak growth; water 1 inch/week | Monitor for pests daily; stake or support as needed |
| July | Continue care | Consistent watering; remove yellow leaves |
| August | — | Dormant season |
| September | — | Dormant season |
| October | — | Dormant season |
| November | First frost approaches | Harvest remaining basil; cover plants on frost nights |
| December | — | Dormant season |
Basil Growing Tips for Missouri Gardeners
- •Never expose basil to temperatures below 50°F — even briefly — it turns black and dies.
- •Pinch flower buds immediately as they appear to keep leaves large and productive.
- •Missouri's moderate climate supports succession planting — sow new transplants or seeds every 3 weeks during spring to extend the harvest window into fall.
- •Harvest by cutting whole stems from the top, leaving lower sets of leaves to branch out.
Companion Planting for Basil in Missouri
In Missouri's moderate climate, planting basil with Tomato and Pepper helps deter pests and improve soil. Avoid planting near Sage and Fennel, which inhibit basil growth through root chemistry or shared pest pressure. See the full basil companion planting guide for the complete list.
Basil Planting Dates by City in Missouri
Top cities in Missouri — select for city-level frost dates and planting calendars.
Frequently Asked Questions
When should I plant basil in Missouri?
In Missouri (Zone 6b), start basil seeds indoors around February 8–15 and transplant outdoors around April 5–15 — 2 weeks after the state's average last frost of March 22.
What is the last frost date in Missouri?
Missouri's average last frost date is March 22 in the state's most common Zone 6b. Frost dates vary by city — higher elevations and northern counties run 1 to 3 weeks later than the state average. See the city list below for city-level frost dates.
Can I grow basil year-round in Missouri?
Not year-round — Missouri's cold season stops basil production. The basil season runs March 22 to November 10, roughly 33 weeks.
What basil varieties grow best in Missouri?
For Missouri's Zone 6b, Sweet Genovese basil is the universal choice; supplement with Thai and Lime basils for variety.
When do I start basil seeds indoors in Missouri?
Start basil seeds indoors in Missouri around February 8–15, which is 6 weeks before the state's average last frost of March 22. Use grow lights and keep soil temperatures at 70–75°F for fastest germination.