When to Plant Sunflower in Colfax County, NE
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.
Colfax County, Nebraska is in USDA Zone 5a. The average last spring frost is April 22 and the first fall frost is October 11, giving you a growing season of approximately 172 days.
At an elevation of 525 feet, Colfax County receives approximately 25 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Sunflower to ensure they mature before fall.
Colfax County Soil Profile
Soil Type
Loam
Soil pH
6.4-7.7
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 — Colfax County, NE
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 25 | Feb 25 – Mar 11 |
| Transplant Outdoors | May 6 | May 6 – May 20 |
| Direct Sow | April 29 | Apr 29 – May 20 |
| Harvest | July 15 | Jul 15 – Sep 2 |
Plant 1" deep · 18" apart · Rows 30" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| 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 5a
Growing Season
172 days
Growing Tips for Colfax 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 Colfax County, NE?
Colfax County is in Zone 5a 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 Colfax County, NE?
Colfax County, Nebraska is in USDA Hardiness Zone 5a. The average last spring frost is April 22 and first fall frost is October 11.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Colfax County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.
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