When to plant Onion in Scott County County,
For Onion in Scott County County, the safe spring window opens around March 31 and closes around April 21. Last expected frost is April 14, first fall frost October 17, giving a 186-day growing season. A second sowing from August 8 to August 22 extends the harvest into fall.
When to Plant Onion in Scott County, IL
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.
Scott County, Illinois is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.
At an elevation of 987 feet, Scott County receives approximately 37.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Onion to ensure they mature before fall.
Scott County Soil Profile
Soil Type
Silt Loam
Soil pH
6-7.1
Drainage
Well Drained
Monthly Watering Guide for Onion
Onion needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Onion Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.8" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3" | 1.3" | 💧 Light watering |
| May | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 5.2" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Aug | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Sep | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Oct | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Nov | — | 2.6" | 0" | ❄️ Dormant |
| Dec | — | 2.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Scott County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Onion Planting Timeline — Scott County, IL
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 10 | Mar 10 – Mar 24 |
| Transplant Outdoors | April 14 | Apr 14 – Apr 28 |
| Direct Sow | March 31 | Mar 31 – Apr 21 |
| Harvest | July 14 | Jul 14 – Sep 1 |
| Fall Sowing | August 8 | Aug 8 – Aug 22 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | — |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 6a
📆 Growing Season
186 days in Scott County
Growing Tips for Scott 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
Check more plant combinations with our Companion Planting Checker →
Onion in Other Locations
Frequently Asked Questions
When should I plant Onion in Scott County, IL?
Scott County is in Zone 6a with an average last frost of April 14. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Scott County, IL?
Scott County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 17.
When should I plant Onion in Scott County County, ?
In Scott County County, , plant Onion after the last frost (around April 14) and before the first frost (around October 17). Best results when soil holds above 50°F.
What growing zone is Scott County County, for Onion?
Scott County County sits in USDA Zone 6a. Onion grows reliably in zones 3a through 10b, so it's a good fit here.
Can Onion grow in Scott County County's climate?
Yes — Onion grows well in Scott County County's temperate climate. Scott County County averages a 186-day frost-free season, with last frost around April 14 and first frost around October 17.
Your Scott County Garden Planner — Free
A 22-page printable planner built for Scott County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.