Zone 9a covers 32 days of last-frost dates. We measured Mobile, AL at Feb 3 and Seattle, WA at Mar 7. 1 of the 10 places we checked in this zone doesn'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 9a
Zone 9a's last spring frost averages Feb 12 and first fall frost Dec 3 — about 294 frost-free days. Arugula 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 22 for a second harvest before frost.
Common questions
How long does arugula take to grow in zone 9a?
Arugula matures in about 30–40 days from sowing. In zone 9a that means sowing around Jan 15 and first picking around Feb 14.
Will arugula survive frost in zone 9a?
Yes — arugula tolerates light frost. In zone 9a you can sow a little before the last frost (around Feb 12) and keep harvesting past the first fall frost (around Dec 3).
Can I plant a second crop of arugula in zone 9a?
Yes — in zone 9a there's time for a fall sowing around Oct 22 for a second harvest before frost.
For soil, spacing, pests and companion planting, see the full arugula growing guide →