When to plant Onion in White County County,
White County County sits in USDA Zone 7a. Plant Onion between March 25 (after last frost on April 8) and April 15. A second sowing from August 18 to September 1 extends the harvest into fall.
When to Plant Onion in White County, IL
Your June planting checklist for White County, Illinois
Your White County, Illinois garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.
July prep starts now
- First harvests: onion
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.
White County, Illinois is in USDA Zone 7a. The average last spring frost is April 8 and the first fall frost is October 27, giving you a growing season of approximately 202 days.
At an elevation of 788 feet, White County receives approximately 30.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Onion during the growing season.
White County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-7
Drainage
Well Drained
Onion 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 White County
How your county's soil matches Onion's growing requirements.
Soil pH
Your soil pH (5.8–7.0) overlaps with Onion's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in White County is excellent for Onion — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.7%) — Onion will thrive.
How to Plant Onion
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Onion Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
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 | — | 1.1" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 2.1" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| May | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Jun | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Jul | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Aug | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Sep | 4.3" | 2.4" | 1.9" | 💧 Light watering |
| Oct | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Nov | — | 2.1" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in White County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Onion Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Onion Planting Timeline — White County, IL
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 4 | Mar 4 – Mar 18 |
| Transplant Outdoors | April 8 | Apr 8 – Apr 22 |
| Direct Sow | March 25 | Mar 25 – Apr 15 |
| Harvest | July 8 | Jul 8 – Aug 26 |
| Fall Sowing | August 18 | Aug 18 – Sep 1 |
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 | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7a
📆 Growing Season
202 days in White County
Growing Tips for Onion in White County
Direct sow Onion outdoors after April 08 in White County when soil has warmed and frost danger has passed.
Common pests for Onion in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.
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
Check more plant combinations with our Companion Planting Checker →
Onion in Other Locations
Frequently Asked Questions
When should I plant Onion in White County, IL?
White County is in Zone 7a with an average last frost of April 8. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is White County, IL?
White County, Illinois is in USDA Hardiness Zone 7a. The average last spring frost is April 8 and first fall frost is October 27.
When should I plant Onion in White County County, ?
In White County County, , plant Onion after the last frost (around April 8) and before the first frost (around October 27). Best results when soil holds above 50°F.
What growing zone is White County County, for Onion?
White County County sits in USDA Zone 7a. Onion grows reliably in zones 3a through 10b, so it's a good fit here.
Can Onion grow in White County County's climate?
Yes — Onion grows well in White County County's temperate climate. White County County averages a 202-day frost-free season, with last frost around April 8 and first frost around October 27.
Your White County Garden Planner — Free
A 22-page printable planner built for White County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.