When to Plant Spinach in Grand Forks County, ND
May in Grand Forks County, North Dakota — your action list
Welcome to May in Zone 4a. These are the moves that will have the biggest impact on your growing season.
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Plant out spinach
Frost risk is low now in Grand Forks County, North Dakota. If you've been covering beds overnight, you can stop.
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Put spinach seeds straight in the ground
These tolerate cool soil, so you're not gambling by sowing now.
Get ahead of June
- Starting indoors: spinach
- First harvests: spinach
Spinach is a nutrient-packed cool-season green that grows quickly in spring and fall. It is rich in iron, vitamins, and antioxidants and excellent raw or cooked.
Grand Forks County, North Dakota is in USDA Zone 4a. The average last spring frost is May 11 and the first fall frost is September 30, giving you a growing season of approximately 142 days.
At an elevation of 572 feet, Grand Forks County receives approximately 27.7 inches of rainfall annually with predominantly loam soil. Summer highs average 79°F, so choose short-season varieties of Spinach to ensure they mature before fall.
Grand Forks County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.4
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 Grand Forks County
How your county's soil matches Spinach's growing requirements.
Soil pH
Your soil pH (6.8–7.4) is within Spinach's preferred range (6.5–7.5).
Soil Texture
The loam soil in Grand Forks County is excellent for Spinach — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.3%). Annual compost additions will help Spinach.
How to Plant Spinach
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Spinach
Sow every 4 weeks. Last sowing by Aug 11 to harvest before frost.
For a dedicated fall crop, sow by Jul 08.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Spinach
Spinach needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.
| Month | Spinach Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 0.8" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | — | 3.2" | 0" | ❄️ Dormant |
| May | 3" | 4.1" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 4.6" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 3" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 3.6" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 2.5" | 0.5" | 💧 Light watering |
| Oct | — | 1.8" | 0" | ❄️ Dormant |
| Nov | — | 0.8" | 0" | ❄️ Dormant |
| Dec | — | 0.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Grand Forks County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Spinach 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.
Spinach Planting Timeline — Grand Forks County, ND
Spinach Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 30 | Mar 30 – Apr 13 |
| Transplant Outdoors | May 11 | May 11 – May 25 |
| Direct Sow | May 4 | May 4 – May 25 |
| Harvest | June 15 | Jun 15 – Aug 17 |
| Fall Sowing | July 8 | Jul 8 – Jul 22 |
Plant 0.5" 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 | Harvest |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.7"/week · Natural rainfall sufficient
📅 Days to Maturity
35–50 days
🧪 Soil pH
Needs 6.5–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 4a
📆 Growing Season
142 days in Grand Forks County
Growing Tips for Spinach in Grand Forks County
Direct sow Spinach outdoors after May 11 in Grand Forks County when soil has warmed and frost danger has passed.
Your generous 142.0-day season in Grand Forks County allows multiple plantings of Spinach. Sow every 17.0 days for continuous harvest.
General growing tips
Direct sow as soon as soil can be worked in spring. Plant in partial shade for summer crops to delay bolting. Succession plant every 2 weeks for continuous harvest.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Wind pollinated — isolate 1/2 mile for purity. Easy to let bolt in heat.
Spinach in Other Locations
Frequently Asked Questions
When should I plant Spinach in Grand Forks County, ND?
Grand Forks County is in Zone 4a with an average last frost of May 11. Plan your Spinach planting based on this frost date — see the calendar above for exact timing.
What planting zone is Grand Forks County, ND?
Grand Forks County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 11 and first fall frost is September 30.
Your Grand Forks County Garden Planner — Free
A 24-page printable planner built for Grand Forks 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.