When to plant kale 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). Kale needs 50–65 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 kale in Arizona: the short answer
For a spring planting, plant out Feb 15 – Mar 4, with seeds started indoors Jan 25 – Feb 8. Seeds germinate in soil from 45 to 85°F.
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 kale in Arizona, step by step
- Start seeds indoors (Jan 25 – Feb 8). Sow seeds ½ inch deep in seed-starting mix under bright light. They take 5-10 days to sprout, fastest in soil around 70°F. Harden seedlings off for a week before they go outside.
- 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 18 inches deep, with a pH between 6.0 and 7.5. Dig in compost before planting.
- Plant out (Feb 15 – Mar 4). Space plants about 16 inches apart in rows 20 inches apart. 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: cabbage worm, cabbage looper, cabbage aphid, flea beetle, harlequin bug. Diseases and disorders: black rot, clubroot, downy mildew.
- Harvest (from about Apr 13 – Apr 28). Kale takes 50-65 days to reach harvest. Flavour turns sweet after a hard frost, so the fall crop is the good one. Pick lower leaves and let the plant keep growing upward.
Figures come from our crop data; dates use Arizona’s average frost dates. More in the full kale growing guide.
Kale 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 kale dates shift with them.
| Zone | Last frost | First frost | Season | Start indoors | Plant kale |
|---|---|---|---|---|---|
| Zone 4 | May 10 | Sep 25 | 135 days | Mar 22 – Apr 5 | Apr 12 – Apr 29 |
| Zone 5 | Apr 30 | Oct 5 | 160 days | Mar 12 – Mar 26 | Apr 2 – Apr 19 |
| Zone 6 | Apr 15 | Oct 15 | 185 days | Feb 25 – Mar 11 | Mar 18 – Apr 4 |
| Zone 7 | Apr 5 | Oct 25 | 200 days | Feb 15 – Mar 1 | Mar 8 – Mar 25 |
| Zone 8 | Mar 20 | Nov 5 | 230 days | Jan 30 – Feb 13 | Feb 20 – Mar 9 |
| Zone 9 | Feb 20 | Nov 30 | 280 days | Jan 2 – Jan 16 | Jan 23 – Feb 9 |
| Zone 10 | Jan 30 | Dec 15 | 330 days | Dec 12 – Dec 26 | Jan 2 – Jan 19 |
When to plant kale in nearby states
| State | Last frost | Plant out |
|---|---|---|
| Arizona (this page) | March 15 | Feb 15 – Mar 4 |
| New Mexico | April 20 | Mar 23 – Apr 9 |
Questions gardeners in Arizona ask
When is the best time to plant kale in Arizona?
Plant kale transplants outdoors in Arizona between February 15 and March 4. 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.
When should I start kale seeds indoors in Arizona?
Start seeds indoors between January 25 and February 8, about 6 weeks before the last frost, so the seedlings are ready to plant out from February 15.
Can I plant kale in the fall in Arizona?
Yes. For a fall crop, sow between August 20 and September 6, so the crop matures in cool weather before Arizona's first frost around November 15.
When will kale planted in Arizona be ready to harvest?
Planted on time, kale is usually ready from about April 13 to April 28, 50-65 days after planting.
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.