When to plant spinach in Arizona
Arizona’s average last spring frost is March 15, and the first fall frost typically arrives around November 15 — about 245 frost-free days (USDA zones 4b, 5b, 6b, 7b, 8b, 9b, 10b). Spinach needs 37–45 days to mature, which fits comfortably within Arizona's growing season.
Arizona 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 Arizona: the short answer
For a spring planting, sow Feb 3 – Feb 22. Seeds germinate in soil from 35 to 75°F.
Succession sow again in Arizona: Feb 20 · Mar 4 · Mar 16 · Mar 28 · Apr 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 Arizona, 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 (Feb 3 – Feb 22). 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 Arizona.
- 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 Mar 17 – Mar 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 Arizona’s average frost dates. More in the full spinach growing guide.
Spinach planting dates by USDA zone in Arizona
Arizona spans USDA zones 4b, 5b, 6b, 7b, 8b, 9b, 10b. 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 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 |
| Zone 9 | Feb 20 | Nov 30 | 280 days | - | Jan 11 – Jan 30 |
| Zone 10 | Jan 30 | Dec 15 | 330 days | - | Dec 21 – Jan 9 |
When to plant spinach in nearby states
| State | Last frost | Sow |
|---|---|---|
| Arizona (this page) | March 15 | Feb 3 – Feb 22 |
| New Mexico | April 20 | Mar 11 – Mar 30 |
Questions gardeners in Arizona ask
When is the best time to plant spinach in Arizona?
Sow spinach in Arizona between February 3 and February 22. That timing is set by Arizona's average last spring frost of March 15; Arizona spans several climates, so cooler and higher parts of the state run later.
Can I plant spinach in the fall in Arizona?
Yes. For a fall crop, sow between September 17 and October 4, so the crop matures in cool weather before Arizona's first frost around November 15.
When will spinach planted in Arizona be ready to harvest?
Planted on time, spinach is usually ready from about March 17 to March 25, 37-45 days after sowing.
When is the last frost in Arizona?
On average around March 15, with the first fall frost around November 15 - about 245 frost-free days. Your town may differ by two weeks or more.