When to Plant Onion in Sioux County, NE
Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.
Sioux County, Nebraska is in USDA Zone 4a. The average last spring frost is May 16 and the first fall frost is September 22, giving you a growing season of approximately 129 days.
At an elevation of 775 feet, Sioux County receives approximately 24.4 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Onion to ensure they mature before fall.
Sioux County Soil Profile
Soil Type
Loam
Soil pH
6.3-7.2
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.
Soil Compatibility in Sioux County
How your county's soil matches Onion's growing requirements.
Soil pH
Your soil pH (6.3–7.2) overlaps with Onion's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in Sioux County is excellent for Onion — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.3%) — Onion will thrive.
How to Plant Onion
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Onion Planting Timeline — Sioux County, NE
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 4 | Apr 4 – Apr 18 |
| Transplant Outdoors | May 16 | May 16 – May 30 |
| Direct Sow | May 9 | May 9 – May 30 |
| Fall Sowing | June 30 | Jun 30 – Jul 14 |
| Harvest | August 15 | Aug 15 – Oct 3 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Fall Sowing |
| July | Fall Sowing |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 4a
📆 Growing Season
129 days in Sioux County
Growing Tips for Onion in Sioux County
Direct sow Onion outdoors after May 16 in Sioux County when soil has warmed and frost danger has passed.
Your 129.0-day growing season in Sioux County is tight for Onion (90.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.
Common pests for Onion in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.
Sioux County receives only 24" of rain annually. Onion needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Onion in Other Locations
Frequently Asked Questions
When should I plant Onion in Sioux County, NE?
Sioux County is in Zone 4a with an average last frost of May 16. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sioux County, NE?
Sioux County, Nebraska is in USDA Hardiness Zone 4a. The average last spring frost is May 16 and first fall frost is September 22.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Sioux County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.
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