When to plant Onion in Jackson County, MN
In Zone 5a (Jackson County), direct-sow Onion between April 16 and May 7 for spring, after the April 30 last-frost mark. A second sowing from July 28 to August 11 extends the harvest into fall.
When to Plant Onion in Jackson County, MN
Top priorities for Jackson County, Minnesota gardeners in June
Your garden in Jackson County, Minnesota is working on a schedule, even when you're not. Here's where you should be this June.
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Begin indoor sowing: onion
You're about 15 weeks out from your last frost — the perfect window to get these germinating indoors.
To set up a strong July, finish these tasks
- 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.
Jackson County, Minnesota is in USDA Zone 5a. The average last spring frost is April 30 and the first fall frost is October 6, giving you a growing season of approximately 159 days.
At an elevation of 1,042 feet, Jackson County receives approximately 37.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Onion to ensure they mature before fall.
Jackson County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-7
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 Jackson County
How your county's soil matches Onion's growing requirements.
Soil pH
Your soil pH (6.1–7.0) is within Onion's preferred range (6.0–7.0).
Soil Texture
The silt loam soil in Jackson County is excellent for Onion — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.2%) — 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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| May | 4.3" | 4.6" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Sep | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Oct | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Nov | — | 2.9" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Jackson 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 — Jackson County, MN
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 26 | Mar 26 – Apr 9 |
| Transplant Outdoors | April 30 | Apr 30 – May 14 |
| Direct Sow | April 16 | Apr 16 – May 7 |
| Harvest | July 30 | Jul 30 – Sep 17 |
| Fall Sowing | July 28 | Jul 28 – Aug 11 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing Harvest |
| August | Fall Sowing Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: ideal
🗺️ USDA Zone
Zone 5a
📆 Growing Season
159 days in Jackson County
Growing Tips for Onion in Jackson County
Direct sow Onion outdoors after April 30 in Jackson 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 Jackson County, MN?
Jackson County is in Zone 5a with an average last frost of April 30. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jackson County, MN?
Jackson County, Minnesota is in USDA Hardiness Zone 5a. The average last spring frost is April 30 and first fall frost is October 6.
When should I plant Onion in Jackson County, MN?
In Jackson County, MN, plant Onion after the last frost (around April 30) and before the first frost (around October 6). Best results when soil holds above 50°F.
What growing zone is Jackson County, MN for Onion?
Jackson County sits in USDA Zone 5a. Onion grows reliably in zones 3a through 10b, so it's a good fit here.
Can Onion grow in Jackson County's climate?
Yes — Onion grows well in Jackson County's temperate climate. Jackson County averages a 159-day frost-free season, with last frost around April 30 and first frost around October 6.
Your Jackson County Garden Planner — Free
A 22-page printable planner built for Jackson County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.