When to Plant Onion in Garfield County, UT
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.
Garfield County, Utah is in USDA Zone 5b. The average last spring frost is May 27 and the first fall frost is September 21, giving you a growing season of approximately 117 days.
At an elevation of 5,058 feet, Garfield County receives approximately 20.3 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.
Garfield County Soil Profile
Soil Type
Loam
Soil pH
6.5-7.7
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 8/10 — consider drought-tolerant varieties and mulching
Onion Planting Timeline — Garfield County, UT
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 22 | Apr 22 – May 6 |
| Transplant Outdoors | May 27 | May 27 – Jun 10 |
| Direct Sow | May 13 | May 13 – Jun 3 |
| Fall Sowing | July 13 | Jul 13 – Jul 27 |
| Harvest | August 26 | Aug 26 – Oct 14 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Start Indoors Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | Fall Sowing |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| 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 5b
Growing Season
117 days
Growing Tips for Garfield 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 Garfield County, UT?
Garfield County is in Zone 5b with an average last frost of May 27. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Garfield County, UT?
Garfield County, Utah is in USDA Hardiness Zone 5b. The average last spring frost is May 27 and first fall frost is September 21.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Garfield County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.
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