When to plant sweet corn in California
California’s average last spring frost is February 20, and the first fall frost typically arrives around December 1 — about 284 frost-free days (USDA zones 5a, 6b, 7b, 8b, 9b, 10a, 10b). Sweet Corn needs 60–100 days to mature, which fits comfortably within California's growing season.
California 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 sweet corn in California: the short answer
For a spring planting, sow Feb 22 – Mar 13. Wait until the soil is at least 55°F and frost is over.
Succession sow again in California: Mar 13 · Mar 27 · Apr 10 · Apr 24 · May 8 · May 22 · Jun 5 · Jun 19
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 sweet corn in California, step by step
- Prepare the bed. It needs at least six to eight hours of direct sun a day and loose soil at least 24 inches deep, with a pH between 5.8 and 7.0. Dig in compost before planting.
- Sow outdoors (Feb 22 – Mar 13). Space plants about 10 inches apart in rows 30 inches apart, sowing seed 1.5 inches deep. It is killed by frost, so nothing goes outside until the danger has passed.
- Water and feed. It needs plenty of water; keep the soil evenly moist and never let it dry out.
- Watch for pests and problems. Pests: corn earworm, European corn borer, corn rootworm, raccoons. Diseases and disorders: common smut, common rust, Stewart's wilt.
- Harvest (from about Apr 28 – Jun 7). Sweet Corn takes 60-100 days to reach harvest. Plant in a block of at least 4 short rows, not one long row, or the ears fill unevenly. Keep sugar-enhanced and supersweet types isolated from field corn. Succeed by sowing every 2 weeks or planting early/mid/late varieties together.
Figures come from our crop data; dates use California’s average frost dates. More in the full sweet corn growing guide.
Sweet Corn planting dates by USDA zone in California
California spans USDA zones 5a, 6b, 7b, 8b, 9b, 10a, 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 sweet corn dates shift with them.
| Zone | Last frost | First frost | Season | Start indoors | Plant sweet corn |
|---|---|---|---|---|---|
| Zone 5 | Apr 30 | Oct 5 | 160 days | - | May 2 – May 21 |
| Zone 6 | Apr 15 | Oct 15 | 185 days | - | Apr 17 – May 6 |
| Zone 7 | Apr 5 | Oct 25 | 200 days | - | Apr 7 – Apr 26 |
| Zone 8 | Mar 20 | Nov 5 | 230 days | - | Mar 22 – Apr 10 |
| Zone 9 | Feb 20 | Nov 30 | 280 days | - | Feb 22 – Mar 13 |
| Zone 10 | Jan 30 | Dec 15 | 330 days | - | Feb 1 – Feb 20 |
Questions gardeners in California ask
When is the best time to plant sweet corn in California?
Sow sweet corn in California between February 22 and March 13. That timing is set by California's average last spring frost of February 20; California spans several climates, so cooler and higher parts of the state run later.
What is the latest I can plant sweet corn in California?
About October 2. Sweet corn needs at least 60 days to mature, and frost around December 1 ends the season, so later plantings risk being cut short.
When will sweet corn planted in California be ready to harvest?
Planted on time, sweet corn is usually ready from about April 28 to June 7, 60-100 days after sowing.
When is the last frost in California?
On average around February 20, with the first fall frost around December 1 - about 284 frost-free days. Your town may differ by two weeks or more.