When to plant swiss chard 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). Swiss Chard needs 50–60 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 swiss chard in California: the short answer
For a spring planting, plant out Jan 30 – Feb 16, with seeds started indoors Jan 16 – Jan 30. Seeds germinate in soil from 40 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 swiss chard in California, step by step
- Start seeds indoors (Jan 16 – Jan 30). Sow seeds 0.75 inch deep in seed-starting mix under bright light. They take 5-14 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 12 inches deep, with a pH between 6.0 and 7.5. Dig in compost before planting.
- Plant out (Jan 30 – Feb 16). Space plants about 9 inches apart in rows 18 inches apart. It tolerates a light frost but not a hard freeze. As a cool-season crop it does best before summer heat arrives in California.
- 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: cercospora leaf spot, downy mildew.
- Harvest (from about Mar 28 – Apr 7). Swiss Chard takes 50-60 days to reach harvest. One of the most heat-tolerant leafy greens - a single spring sowing usually carries through summer into fall if kept picked.
Figures come from our crop data; dates use California’s average frost dates. More in the full swiss chard growing guide.
Swiss Chard 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 swiss chard dates shift with them.
| Zone | Last frost | First frost | Season | Start indoors | Plant swiss chard |
|---|---|---|---|---|---|
| Zone 5 | Apr 30 | Oct 5 | 160 days | Mar 26 – Apr 9 | Apr 9 – Apr 26 |
| Zone 6 | Apr 15 | Oct 15 | 185 days | Mar 11 – Mar 25 | Mar 25 – Apr 11 |
| Zone 7 | Apr 5 | Oct 25 | 200 days | Mar 1 – Mar 15 | Mar 15 – Apr 1 |
| Zone 8 | Mar 20 | Nov 5 | 230 days | Feb 13 – Feb 27 | Feb 27 – Mar 16 |
| Zone 9 | Feb 20 | Nov 30 | 280 days | Jan 16 – Jan 30 | Jan 30 – Feb 16 |
| Zone 10 | Jan 30 | Dec 15 | 330 days | Dec 26 – Jan 9 | Jan 9 – Jan 26 |
Questions gardeners in California ask
When is the best time to plant swiss chard in California?
Plant swiss chard transplants outdoors in California between January 30 and February 16. 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.
When should I start swiss chard seeds indoors in California?
Start seeds indoors between January 16 and January 30, about 4 weeks before the last frost, so the seedlings are ready to plant out from January 30.
Can I plant swiss chard in the fall in California?
Yes. For a fall crop, sow between September 12 and September 29, so the crop matures in cool weather before California's first frost around December 1.
When will swiss chard planted in California be ready to harvest?
Planted on time, swiss chard is usually ready from about March 28 to April 7, 50-60 days after planting.
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.