Zone 7a covers 30 days of last-frost dates. We measured Fayetteville, AR at Mar 31 and Ogden, UT at Apr 30. 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 7a
Zone 7a's last spring frost averages Apr 13 and first fall frost Nov 12 — about 213 frost-free days. Zinnia is frost-sensitive, so the around last frost timing builds in a safety margin against a late cold snap — setting plants out too early risks losing them to frost. Starting seeds indoors 4 weeks ahead gives strong transplants ready the moment the soil warms.
Common questions
How long does zinnia take to grow in zone 7a?
Zinnia matures in about 50–70 days from sowing. In zone 7a that means sowing around Apr 13 and first picking around Jun 2.
Will zinnia survive frost in zone 7a?
No — zinnia is frost-sensitive. In zone 7a, wait until after the last frost (around Apr 13) to plant, and harvest before the first fall frost (around Nov 12).
For soil, spacing, pests and companion planting, see the full zinnia growing guide →