When to plant Sunflower in Warren County, MO
Warren County's climate puts the Sunflower spring window between April 11 and May 2. time plantings around the expected last-frost window for best survival.
When to Plant Sunflower in Warren County, MO
Sunflower (Helianthus annuus) is a fast-growing North American native annual famous for its towering stems and brilliant yellow heads. It thrives in full sun and heat, producing large, pollen-rich blooms that attract bees, butterflies, and seed-eating birds. Varieties range from 18-inch dwarfs to 12-foot giants and nearly every color except blue.
Warren County, Missouri is in USDA Zone 6b. The average last spring frost is April 11 and the first fall frost is October 25, giving you a growing season of approximately 197 days.
At an elevation of 654 feet, Warren County receives approximately 30 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Sunflower during the growing season.
Warren County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Sunflower Planting Timeline — Warren County, MO
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 21 | Mar 21 – Apr 4 |
| Transplant Outdoors | April 11 | Apr 11 – Apr 25 |
| Direct Sow | April 11 | Apr 11 – May 2 |
| Bloom | July 4 | Jul 4 – Oct 3 |
Plant 1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Direct Sow |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
70–100 days
🧪 Soil pH
Needs 6–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 6b
📆 Growing Season
197 days in Warren County
Growing Tips for Warren County
Direct-sow 1 inch deep after last frost; germination takes 7-14 days at 65-75°F soil. Sunflowers dislike root disturbance so direct sowing is strongly preferred over transplanting. Plant in succession every 2 weeks for extended bloom. Stake tall varieties. Avoid overwatering — they tolerate drought once established. Birds will self-deadhead seed heads; leave them up through fall for wildlife.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Sunflower in Other Locations
Frequently Asked Questions
When should I plant Sunflower in Warren County, MO?
Warren County is in Zone 6b with an average last frost of April 11. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Warren County, MO?
Warren County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 11 and first fall frost is October 25.
When should I plant Sunflower in Warren County, MO?
In Warren County, MO, plant Sunflower after the last frost (around April 11) and before the first frost (around October 25). Best results when soil holds above 50°F.
What growing zone is Warren County, MO for Sunflower?
Warren County sits in USDA Zone 6b. Sunflower grows reliably in zones 2a through 11b, so it's a good fit here.
Can Sunflower grow in Warren County's climate?
Yes — Sunflower grows well in Warren County's temperate climate. Warren County averages a 197-day frost-free season, with last frost around April 11 and first frost around October 25.
Your Warren County Garden Planner — Free
A 22-page printable planner built for Warren County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.