Why these dates work in zone 4a
Zone 4a's last spring frost averages May 7 and first fall frost Oct 13 — about 159 frost-free days. Spinach 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 Aug 18 for a second harvest before frost.
Common questions
How long does spinach take to grow in zone 4a?
Spinach matures in about 37–50 days from sowing. In zone 4a that means sowing around Apr 9 and first picking around May 16.
Will spinach survive frost in zone 4a?
Yes — spinach tolerates light frost. In zone 4a you can sow a little before the last frost (around May 7) and keep harvesting past the first fall frost (around Oct 13).
Can I plant a second crop of spinach in zone 4a?
Yes — in zone 4a there's time for a fall sowing around Aug 18 for a second harvest before frost.
For soil, spacing, pests and companion planting, see the full spinach growing guide →