When to Plant Onion in Simpson County, MS
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.
Simpson County, Mississippi is in USDA Zone 8a. The average last spring frost is March 10 and the first fall frost is November 15, giving you a growing season of approximately 250 days.
At an elevation of 90 feet, Simpson County receives approximately 48.4 inches of rainfall annually with predominantly clay loam soil. Summer highs average 97°F, so Onion may need afternoon shade and extra watering during peak heat. Clay soil retains moisture well for Onion, but amend with compost to improve drainage and prevent root rot.
Simpson County Soil Profile
Soil Type
Clay Loam
Soil pH
5.6-6.8
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
Onion Planting Timeline — Simpson County, MS
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 3 | Feb 3 – Feb 17 |
| Transplant Outdoors | March 10 | Mar 10 – Mar 24 |
| Direct Sow | February 24 | Feb 24 – Mar 17 |
| Fall Sowing | September 6 | Sep 6 – Sep 20 |
| Harvest | June 9 | Jun 9 – Jul 28 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors Direct Sow |
| March | Transplant Outdoors Direct Sow |
| April | — |
| May | — |
| June | Harvest |
| July | Harvest |
| August | — |
| September | Fall Sowing |
| 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 8a
Growing Season
250 days
Growing Tips for Simpson 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 Simpson County, MS?
Simpson County is in Zone 8a with an average last frost of March 10. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Simpson County, MS?
Simpson County, Mississippi is in USDA Hardiness Zone 8a. The average last spring frost is March 10 and first fall frost is November 15.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Simpson County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.
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