When to plant radishes 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). Radish needs 22–30 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 radishes in Arizona: the short answer
For a spring planting, sow Feb 10 – Mar 1. Seeds germinate in soil from 40 to 85°F.
Succession sow again in Arizona: Feb 25 · Mar 7 · Mar 17 · Mar 27 · Apr 6 · Apr 16
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 radishes in Arizona, step by step
- Prepare the bed. They need 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 6 inches deep, with a pH between 6.0 and 7.0. Dig in compost before planting.
- Sow outdoors (Feb 10 – Mar 1). Space plants about 2 inches apart in rows 6 inches apart, sowing seed ½ inch deep. It handles frost well, so it can go out before the last frost date. 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: flea beetle, cabbage root maggot, aphids. Diseases and disorders: clubroot, scab, downy mildew.
- Harvest (from about Mar 9 – Mar 17). Radish takes 22-30 days to reach harvest. The classic marker crop and quick filler. Sow a short row every 10 days - a single big sowing all matures at once and then goes pithy and hot.
Figures come from our crop data; dates use Arizona’s average frost dates. More in the full radish growing guide.
Radish 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 radish dates shift with them.
| Zone | Last frost | First frost | Season | Start indoors | Plant radish |
|---|---|---|---|---|---|
| Zone 4 | May 10 | Sep 25 | 135 days | - | Apr 7 – Apr 26 |
| Zone 5 | Apr 30 | Oct 5 | 160 days | - | Mar 28 – Apr 16 |
| Zone 6 | Apr 15 | Oct 15 | 185 days | - | Mar 13 – Apr 1 |
| Zone 7 | Apr 5 | Oct 25 | 200 days | - | Mar 3 – Mar 22 |
| Zone 8 | Mar 20 | Nov 5 | 230 days | - | Feb 15 – Mar 6 |
| Zone 9 | Feb 20 | Nov 30 | 280 days | - | Jan 18 – Feb 6 |
| Zone 10 | Jan 30 | Dec 15 | 330 days | - | Dec 28 – Jan 16 |
When to plant radishes in nearby states
| State | Last frost | Sow |
|---|---|---|
| Arizona (this page) | March 15 | Feb 10 – Mar 1 |
| New Mexico | April 20 | Mar 18 – Apr 6 |
Questions gardeners in Arizona ask
When is the best time to plant radishes in Arizona?
Sow radishes in Arizona between February 10 and March 1. 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 radishes in the fall in Arizona?
Yes. For a fall crop, sow between October 1 and October 18, so the crop matures in cool weather before Arizona's first frost around November 15.
When will radishes planted in Arizona be ready to harvest?
Planted on time, radishes are usually ready from about March 9 to March 17, 22-30 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.