When to plant Sunflower in Atchison County, MO
In Atchison County, plant Sunflower in spring between April 29 and May 20, once soil temps hold above 50°F. Atchison County's last frost averages April 22, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between and — roughly 70–100 days before the first frost on October 13.
When to Plant Sunflower in Atchison 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.
Atchison County, Missouri is in USDA Zone 5b. The average last spring frost is April 22 and the first fall frost is October 13, giving you a growing season of approximately 174 days.
At an elevation of 1,206 feet, Atchison County receives approximately 39.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Sunflower to ensure they mature before fall.
Atchison County Soil Profile
Soil Type
Silt Loam
Soil pH
5.3-6.8
Drainage
Well Drained
Monthly Watering Guide for Sunflower
Sunflower needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Sunflower Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.9" | 0" | ❄️ Dormant |
| Mar | — | 3.1" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| May | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4.6" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Aug | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Oct | 4.3" | 3" | 1.3" | 💧 Light watering |
| Nov | — | 3.2" | 0" | ❄️ Dormant |
| Dec | — | 2.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Atchison County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Sunflower Planting Timeline — Atchison County, MO
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 1 | Apr 1 – Apr 15 |
| Transplant Outdoors | April 29 | Apr 29 – May 13 |
| Direct Sow | April 29 | Apr 29 – May 20 |
| Bloom | July 22 | Jul 22 – Oct 7 |
Plant 1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Transplant Outdoors 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 5b
📆 Growing Season
174 days in Atchison County
Growing Tips for Atchison 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 Atchison County, MO?
Atchison County is in Zone 5b with an average last frost of April 22. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Atchison County, MO?
Atchison County, Missouri is in USDA Hardiness Zone 5b. The average last spring frost is April 22 and first fall frost is October 13.
When should I plant Sunflower in Atchison County, MO?
In Atchison County, MO, plant Sunflower after the last frost (around April 22) and before the first frost (around October 13). Best results when soil holds above 50°F.
What growing zone is Atchison County, MO for Sunflower?
Atchison County sits in USDA Zone 5b. Sunflower grows reliably in zones 2a through 11b, so it's a good fit here.
Can Sunflower grow in Atchison County's climate?
Yes — Sunflower grows well in Atchison County's temperate climate. Atchison County averages a 174-day frost-free season, with last frost around April 22 and first frost around October 13.
Your Atchison County Garden Planner — Free
A 22-page printable planner built for Atchison 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.