When to plant Onion in Macon County, IL
Macon County sits in USDA Zone 6a. Plant Onion between March 30 (after last frost on April 13) and April 20. A second sowing from August 10 to August 24 extends the harvest into fall.
When to Plant Onion in Macon County, IL
July to-do list for Macon County, Illinois
We've pulled the most time-sensitive tasks for Macon County, Illinois this July and put them front and centre. Tackle them in order.
-
Collect onion at their peak
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
Looking ahead to August
- First harvests: onion
- Fall sowing: 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.
Macon County, Illinois is in USDA Zone 6a. The average last spring frost is April 13 and the first fall frost is October 19, giving you a growing season of approximately 189 days.
At an elevation of 1,064 feet, Macon County receives approximately 31.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Onion during the growing season.
Macon County Soil Profile
Soil Type
Silt Loam
Soil pH
6-7.1
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 Macon County
How your county's soil matches Onion's growing requirements.
Soil pH
Your soil pH (6.0–7.1) overlaps with Onion's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Macon County is excellent for Onion — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.3%) — Onion will thrive.
How to Plant Onion
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Onion Water Budget
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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.2" | 0" | ❄️ Dormant |
| Apr | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| May | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Jun | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Jul | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Aug | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Sep | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Oct | 4.3" | 2.3" | 2" | 💧 Light watering |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 1.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Macon 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 — Macon County, IL
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 9 | Mar 9 – Mar 23 |
| Transplant Outdoors | April 13 | Apr 13 – Apr 27 |
| Direct Sow | March 30 | Mar 30 – Apr 20 |
| Harvest | July 13 | Jul 13 – Aug 31 |
| Fall Sowing | August 10 | Aug 10 – Aug 24 |
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 | — |
| 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 6a
📆 Growing Season
189 days in Macon County
Growing Tips for Onion in Macon County
Direct sow Onion outdoors after April 13 in Macon 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 Macon County, IL?
Macon County is in Zone 6a with an average last frost of April 13. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Macon County, IL?
Macon County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 13 and first fall frost is October 19.
When should I plant Onion in Macon County, IL?
In Macon County, IL, plant Onion after the last frost (around April 13) and before the first frost (around October 19). Best results when soil holds above 50°F.
What growing zone is Macon County, IL for Onion?
Macon 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 Macon County's climate?
Yes — Onion grows well in Macon County's temperate climate. Macon County averages a 189-day frost-free season, with last frost around April 13 and first frost around October 19.
Your Macon County Garden Planner — Free
A 22-page printable planner built for Macon 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.