When to Plant Onion in Sheridan County, ND
Sheridan County, North Dakota gardeners: here's your May plan
Here's what deserves your attention in Sheridan County, North Dakota this month. Everything below is tailored to Zone 4a and timed around your local frost dates.
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Time to transplant onion
Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.
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Outdoor sowing time: onion
Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.
To set up a strong June, finish these tasks
- Starting indoors: 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.
Sheridan County, North Dakota is in USDA Zone 4a. The average last spring frost is May 12 and the first fall frost is October 1, giving you a growing season of approximately 142 days.
At an elevation of 1,070 feet, Sheridan County receives approximately 24.1 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Onion to ensure they mature before fall.
Sheridan County Soil Profile
Soil Type
Loam
Soil pH
6.4-7.5
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.
Soil Compatibility in Sheridan County
How your county's soil matches Onion's growing requirements.
Soil pH
Your soil pH (6.4–7.5) overlaps with Onion's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in Sheridan County is excellent for Onion — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.5%). Annual compost additions will help Onion.
How to Plant Onion
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Plant 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 | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2" | 0" | ❄️ Dormant |
| Apr | — | 2.4" | 0" | ❄️ Dormant |
| May | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| Jun | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Jul | 4.3" | 2.4" | 1.9" | 💧 Light watering |
| Aug | 4.3" | 2.2" | 2.1" | 💧 Light watering |
| Sep | 4.3" | 1.9" | 2.4" | 🚿 Regular watering |
| Oct | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Nov | — | 1.9" | 0" | ❄️ Dormant |
| Dec | — | 1.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Sheridan 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 — Sheridan County, ND
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 31 | Mar 31 – Apr 14 |
| Transplant Outdoors | May 12 | May 12 – May 26 |
| Direct Sow | May 5 | May 5 – May 26 |
| Harvest | August 11 | Aug 11 – Sep 29 |
| Fall Sowing | July 9 | Jul 9 – Jul 23 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing |
| August | Harvest |
| September | Harvest |
| 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 4a
📆 Growing Season
142 days in Sheridan County
Growing Tips for Onion in Sheridan County
Direct sow Onion outdoors after May 12 in Sheridan 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.
Sheridan County receives only 24" of rain annually. Onion needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
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 Sheridan County, ND?
Sheridan County is in Zone 4a with an average last frost of May 12. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sheridan County, ND?
Sheridan County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 12 and first fall frost is October 1.
Your Sheridan County Garden Planner — Free
A 24-page printable planner built for Sheridan County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.