When to plant spinach in North Dakota
North Dakota’s average last spring frost is May 15, and the first fall frost typically arrives around September 20 — about 128 frost-free days (USDA zones 3a, 3b, 4a, 4b). Spinach needs 37–45 days to mature, which fits comfortably within North Dakota's growing season.
When to plant spinach in North Dakota: the short answer
For a spring planting, sow Apr 5 – Apr 24. Seeds germinate in soil from 35 to 75°F.
Succession sow again in North Dakota: Apr 22 · May 4 · May 16 · May 28 · Jun 9
Spring succession stops before summer heat makes it bolt. Start sowing again in late summer for a fall crop (see the fall window above).
Windows are ~1–2 week bands around each date. Frost dates are a statewide average from NOAA/NCEI normals; your town may differ by two weeks or more. Calendar year 2026.
How to grow spinach in North Dakota, step by step
- Prepare the bed. It needs six or more hours of sun for the best growth, though four to six hours in partial shade is enough and loose soil at least 12 inches deep, with a pH between 6.0 and 7.5. Dig in compost before planting.
- Sow outdoors (Apr 5 – Apr 24). Space plants about 4 inches apart in rows 12 inches apart, sowing seed ½ inch deep. It tolerates hard frost, so it is one of the first crops to plant. As a cool-season crop it does best before summer heat arrives in North Dakota.
- Water and feed. Give it steady, even moisture, about an inch of water a week from rain or the hose.
- Watch for pests and problems. Pests: leaf miner, aphids, flea beetle. Diseases and disorders: downy mildew, white rust, damping off.
- Harvest (from about May 17 – May 25). Spinach takes 37-45 days to reach harvest. Bolts fast in heat and long days - it is really a spring and fall crop. A late-fall sowing under row cover often overwinters for an early-spring cut.
Figures come from our crop data; dates use North Dakota’s average frost dates. More in the full spinach growing guide.
Spinach planting dates by USDA zone in North Dakota
North Dakota spans USDA zones 3a, 3b, 4a, 4b. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average, so the spinach dates shift with them.
When to plant spinach in nearby states
| State | Last frost | Sow |
|---|---|---|
| North Dakota (this page) | May 15 | Apr 5 – Apr 24 |
| South Dakota | May 10 | Mar 31 – Apr 19 |
| Nebraska | April 30 | Mar 21 – Apr 9 |
| Kansas | April 15 | Mar 6 – Mar 25 |
| Oklahoma | April 1 | Feb 20 – Mar 11 |
Questions gardeners in North Dakota ask
When is the best time to plant spinach in North Dakota?
Sow spinach in North Dakota between April 5 and April 24. That timing is set by North Dakota's average last spring frost of May 15.
Can I plant spinach in the fall in North Dakota?
Yes. For a fall crop, sow between July 23 and August 9, so the crop matures in cool weather before North Dakota's first frost around September 20.
When will spinach planted in North Dakota be ready to harvest?
Planted on time, spinach is usually ready from about May 17 to May 25, 37-45 days after sowing.
When is the last frost in North Dakota?
On average around May 15, with the first fall frost around September 20 - about 128 frost-free days. Your town may differ by two weeks or more.