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. Mustard Greens tolerates light frost, so you can sow ahead of the last-frost date and keep harvesting into the cooler fall. There's also room for a fall succession sowing around Oct 27 for a second harvest before frost.
Common questions
How long does mustard greens take to grow in zone 9b?
Mustard Greens matures in about 25–40 days from sowing. In zone 9b that means sowing around Jan 12 and first picking around Feb 6.
Will mustard greens survive frost in zone 9b?
Yes — mustard greens 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 mustard greens in zone 9b?
Yes — in zone 9b there's time for a fall sowing around Oct 27 for a second harvest before frost.
For soil, spacing, pests and companion planting, see the full mustard greens growing guide →