Zone 8a covers 26 days of last-frost dates. We measured Little Rock, AR at Mar 9 and Baltimore, MD at Apr 4. 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 8a
Zone 8a's last spring frost averages Mar 15 and first fall frost Nov 19 — about 249 frost-free days. Onion tolerates light frost, so you can sow ahead of the last-frost date and keep harvesting into the cooler fall. Starting seeds indoors 10 weeks ahead gives strong transplants ready the moment the soil warms.
Common questions
How long does onion take to grow in zone 8a?
Onion matures in about 90–110 days from sowing. In zone 8a that means sowing around Mar 1 and first picking around May 30.
Will onion survive frost in zone 8a?
Yes — onion tolerates light frost. In zone 8a you can sow a little before the last frost (around Mar 15) and keep harvesting past the first fall frost (around Nov 19).
For soil, spacing, pests and companion planting, see the full onion growing guide →