When to plant spinach in Alaska
Alaska’s average last spring frost is May 17, and the first fall frost typically arrives around September 13 — about 119 frost-free days (USDA zones 1a, 2b, 3b, 4b, 5b, 6b, 7b, 8b). Spinach needs 37–45 days to mature, which fits comfortably within Alaska's growing season.
Alaska covers a wide range of climates, so your exact frost dates may differ from the state average by two weeks or more. For dates tuned to your town, use the calendar generator.
When to plant spinach in Alaska: the short answer
For a spring planting, sow Apr 7 – Apr 26. Seeds germinate in soil from 35 to 75°F.
Succession sow again in Alaska: Apr 24 · May 6 · May 18 · May 30 · Jun 11
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 Alaska, 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 7 – Apr 26). 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 Alaska.
- 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 19 – May 27). 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 Alaska’s average frost dates. More in the full spinach growing guide.
Spinach planting dates by USDA zone in Alaska
Alaska spans USDA zones 1a, 2b, 3b, 4b, 5b, 6b, 7b, 8b. 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.
| Zone | Last frost | First frost | Season | Start indoors | Plant spinach |
|---|---|---|---|---|---|
| Zone 1 | Jun 15 | Aug 20 | 65 days | - | May 6 – May 25 |
| Zone 2 | Jun 1 | Sep 1 | 90 days | - | Apr 22 – May 11 |
| Zone 3 | May 15 | Sep 15 | 120 days | - | Apr 5 – Apr 24 |
| Zone 4 | May 10 | Sep 25 | 135 days | - | Mar 31 – Apr 19 |
| Zone 5 | Apr 30 | Oct 5 | 160 days | - | Mar 21 – Apr 9 |
| Zone 6 | Apr 15 | Oct 15 | 185 days | - | Mar 6 – Mar 25 |
| Zone 7 | Apr 5 | Oct 25 | 200 days | - | Feb 24 – Mar 15 |
| Zone 8 | Mar 20 | Nov 5 | 230 days | - | Feb 8 – Feb 27 |
When to plant spinach in nearby states
| State | Last frost | Sow |
|---|---|---|
| Alaska (this page) | May 17 | Apr 7 – Apr 26 |
| Hawaii | frost-free | - |
Questions gardeners in Alaska ask
When is the best time to plant spinach in Alaska?
Sow spinach in Alaska between April 7 and April 26. That timing is set by Alaska's average last spring frost of May 17; Alaska spans several climates, so cooler and higher parts of the state run later.
Can I plant spinach in the fall in Alaska?
Yes. For a fall crop, sow between July 16 and August 2, so the crop matures in cool weather before Alaska's first frost around September 13.
When will spinach planted in Alaska be ready to harvest?
Planted on time, spinach is usually ready from about May 19 to May 27, 37-45 days after sowing.
When is the last frost in Alaska?
On average around May 17, with the first fall frost around September 13 - about 119 frost-free days. Your town may differ by two weeks or more.