Swiss Chard in Zone 10a & 10b
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Yes, Swiss chard grows in zones 10a and 10b. Start seeds indoors in Aug–Jan and plant out in Sep–Feb. For a fall crop, start seeds indoors in Aug–Jan and plant out in Sep–Feb.
When to plant Swiss chard in zone 10b
Zones 10a and 10b share the same average frost dates, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. In your zone it needs a head start on the heat that direct-sowing elsewhere doesn't require.
| Window | Fall window |
|---|---|
| Start indoors | Aug–Jan |
| Direct sow / transplant outside | Sep–Feb |
| Estimated harvest | ~55 days after transplanting |
Spacing: 4 per square foot (square-foot-gardening spacing). Mature height: 1-2 ft.
Zone 10b dates sourced from growinginthegarden.com.
Fall window: the last sowing date is the average first frost minus days to maturity, the method in Purdue Extension's fall garden guide, which lists Swiss chard for late-summer planting.
Plant alongside it in zone 10b
These go outside within two weeks of Swiss chard in zone 10b, so one planting day can cover them.
Swiss chard does what spinach and lettuce can't: keep producing through the heat of summer without bolting. It can be started indoors or direct-seeded, and a single planting will often keep giving cut-and-come-again harvests for months.
How Swiss chard fits zone 10's season
Zone 10b's frost-free window runs about 324 days, from January 30 to December 20. Swiss chard needs about 55 days from sowing to first harvest.
Swiss Chard planting windows in every zone
Zone 10b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Harvest |
|---|---|---|---|
| 3a & 3b | May 2–May 9 | May 16–May 23 | Jul 10–Jul 17 |
| 4a & 4bSpring window | Apr 17–Apr 24 | May 1–May 8 | Jun 25–Jul 2 |
| Fall window | Not usually | Jul 13–Jul 27 | Sep 6–Sep 20 |
| 5a & 5bSpring window | Apr 12–Apr 19 | Apr 26–May 3 | Jun 20–Jun 27 |
| Fall window | Not usually | Jul 28–Aug 11 | Sep 21–Oct 5 |
| 6a & 6bSpring window | Mar 28–Apr 4 | Apr 11–Apr 18 | Jun 5–Jun 12 |
| Fall window | Not usually | Aug 7–Aug 21 | Oct 1–Oct 15 |
| 7a & 7bSpring window | Mar 13–Mar 20 | Mar 27–Apr 3 | May 21–May 28 |
| Fall window | Not usually | Aug 17–Aug 31 | Oct 11–Oct 25 |
| 8a & 8bSpring window | Feb 25–Mar 4 | Mar 11–Mar 18 | May 5–May 12 |
| Fall window | Not usually | Sep 2–Sep 16 | Oct 27–Nov 10 |
| 9a & 9bSpring window | Jan 18–Jan 25 | Feb 1–Feb 8 | Mar 28–Apr 4 |
| Fall window | Not usually | Sep 27–Oct 11 | Nov 21–Dec 5 |
| 10a & 10bFall window (your zone) | Aug–Jan | Sep–Feb | ~55 days after transplanting |
Harvest dates are about 55 days after the sow or plant-out date, not after starting seeds indoors.
Good companions
- Bush Beans: Beans fix nitrogen chard uses heavily.
Where to buy Swiss chard seeds
Botanical Interests · Burpee (each supplier's Swiss chard seeds)
Varieties we recommend, and where to get them:
- Bright Lights: The gold-standard rainbow chard, an AAS winner at 55 days with savoyed leaves and stems in gold, pink, orange, red and white on the same planting. Buy: True Leaf Market · Burpee Full notes
- Fordhook Giant: The traditional white-stemmed, green-leaf standard Johnny's rates as a strong, heat-tolerant performer at about 50 days. Buy: Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds Full notes
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing Swiss chard" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 10b calendar · Plan your beds in the Garden Designer →
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Growing Swiss Chard in USDA zone 10b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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