When to Plant Sunflower in Linn County, KS
Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.
Linn County, Kansas is in USDA Zone 6a. The average last spring frost is April 9 and the first fall frost is October 25, giving you a growing season of approximately 199 days.
At an elevation of 434 feet, Linn County receives approximately 33 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Sunflower during the growing season.
Linn County Soil Profile
Soil Type
Loam
Soil pH
6.6-7.2
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.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Sunflower Planting Timeline — Linn County, KS
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 12 | Feb 12 – Feb 26 |
| Transplant Outdoors | April 23 | Apr 23 – May 7 |
| Direct Sow | April 16 | Apr 16 – May 7 |
| Harvest | July 2 | Jul 2 – Aug 20 |
Plant 1" deep · 18" apart · Rows 30" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | — |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Low — drought tolerant
Days to Maturity
70–100 days
Soil pH
6 – 7.5
USDA Zone
Zone 6a
Growing Season
199 days
Growing Tips for Linn County
Direct sow after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Sunflower in Other Locations
Frequently Asked Questions
When should I plant Sunflower in Linn County, KS?
Linn County is in Zone 6a with an average last frost of April 9. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Linn County, KS?
Linn County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 9 and first fall frost is October 25.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Linn County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.
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