North Dakota · zones 4a–4a
When to plant spinach in North Dakota.
Sow between Mar 24 to May 5 in a typical year, keyed to North Dakota's median last frost around May 15. A second, fall sowing fits Jul 9 to Aug 27. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Spinach dates for a typical North Dakota season.
Direct sow
Mar 24 to May 5
Keyed to the ~May 15 last frost. Sow 0.5" deep, 3" apart.
Fall round
Jul 9 to Aug 27
Counted back from the ~Sep 22 first frost.
Harvest
~42 days later
~0.25 lb per plant over ~1 weeks.
North Dakota spans more than one climate: Zone 4 is the most common zone, but the state runs 4a to 4a. That's why the planner works from your ZIP code's frost dates, not your zone: mountain and coastal gardens in the same state can be three weeks apart.
In North Dakota: watch for
The pests that find spinach here.
The short season here, about 130 frost-free days, keeps spinach in front of leaf miners only briefly. One early row cover usually carries a planting through the worst of it.
Winding pale tunnels or blotches inside the leaves.
Organic fix: Pick and destroy mined leaves; cover the row.
Cercospora leaf spot
Round spots with gray centers and a red-purple rim, oldest leaves worst.
Organic fix: Space wider so leaves dry fast, clear old debris, and pull pigweed and lambsquarters nearby.
Your season math: North Dakota gives spinach about 130 frost-free days, and it needs roughly 42 days to a first harvest. That fits about 13 re-sown rounds across the season, so you can keep it coming instead of picking once.
Planting spinach in North Dakota: questions
When should I plant spinach in North Dakota?+
In a typical North Dakota year, sow spinach between Mar 24 to May 5, keyed to the state's median last frost around May 15. There's also a fall window: Jul 9 to Aug 27. Your exact dates shift with your ZIP code and microclimate.
What USDA zone is North Dakota?+
North Dakota spans zones 4a–4a, mostly zone 4. But frost dates, not zones, set planting time. The free planner uses your ZIP code's actual frost dates.
How many spinach plants do I need?+
Depends who you're feeding. The crop page has exact counts per household size, or the free planner does the math for your family in about 60 seconds.