When to Plant Onion in Yuba County, CA
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.
Yuba County, California is in USDA Zone 9a. The average last spring frost is April 22 and the first fall frost is November 9, giving you a growing season of approximately 201 days.
At an elevation of 303 feet, Yuba County receives approximately 26.5 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Onion during the growing season.
Yuba County Soil Profile
Soil Type
Loam
Soil pH
6.3-7.3
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 8/10 — consider drought-tolerant varieties and mulching
Onion Planting Timeline — Yuba County, CA
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 25 | Mar 25 – Apr 8 |
| Transplant Outdoors | April 22 | Apr 22 – May 6 |
| Direct Sow | April 1 | Apr 1 – Apr 22 |
| Fall Sowing | September 14 | Sep 14 – Sep 28 |
| Harvest | July 22 | Jul 22 – Sep 9 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Transplant Outdoors |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Fall Sowing Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
90–120 days
Soil pH
6 – 7
USDA Zone
Zone 9a
Growing Season
201 days
Growing Tips for Yuba County
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 Yuba County, CA?
Yuba County is in Zone 9a with an average last frost of April 22. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Yuba County, CA?
Yuba County, California is in USDA Hardiness Zone 9a. The average last spring frost is April 22 and first fall frost is November 9.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Yuba County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.
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