Zone 9b covers 17 days of last-frost dates. We measured Las Vegas, NV at Feb 6 and Sacramento, CA at Feb 23. 10 of the 15 places we checked in this zone don't dependably freeze at all. Give us your town or ZIP and we'll use ten years of daily lows recorded at your own coordinates instead of the middle of that range.
Why these dates work in zone 9b
Zone 9b's last spring frost averages Feb 9 and first fall frost Dec 8 — about 302 frost-free days. Swiss Chard tolerates light frost, so you can sow ahead of the last-frost date and keep harvesting into the cooler fall. Starting seeds indoors 4 weeks ahead gives strong transplants ready the moment the soil warms. There's also room for a fall succession sowing around Sep 29 for a second harvest before frost.
Common questions
How long does swiss chard take to grow in zone 9b?
Swiss Chard matures in about 50–60 days from sowing. In zone 9b that means sowing around Jan 26 and first picking around Mar 17.
Will swiss chard survive frost in zone 9b?
Yes — swiss chard tolerates light frost. In zone 9b you can sow a little before the last frost (around Feb 9) and keep harvesting past the first fall frost (around Dec 8).
Can I plant a second crop of swiss chard in zone 9b?
Yes — in zone 9b there's time for a fall sowing around Sep 29 for a second harvest before frost.
For soil, spacing, pests and companion planting, see the full swiss chard growing guide →