Zone 6b covers 17 days of last-frost dates. We measured Springfield, MO at Apr 6 and Detroit, MI at Apr 23. 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 6b
Zone 6b's last spring frost averages Apr 19 and first fall frost Nov 6 — about 201 frost-free days. Broccoli tolerates light frost, so you can set plants out ahead of the last-frost date and keep harvesting into the cooler fall. Starting seeds indoors 6 weeks ahead gives strong transplants ready the moment the soil warms. There's also room for a fall succession sowing around Aug 7 for a second harvest before frost.
Common questions
How long does broccoli take to grow in zone 6b?
Broccoli matures in about 80–100 days from transplanting. In zone 6b that means setting plants out around Mar 29 and first picking around Jun 17.
Will broccoli survive frost in zone 6b?
Yes — broccoli tolerates light frost. In zone 6b you can set plants out a little before the last frost (around Apr 19) and keep harvesting past the first fall frost (around Nov 6).
Can I plant a second crop of broccoli in zone 6b?
Yes — in zone 6b there's time for a fall sowing around Aug 7 for a second harvest before frost.
For soil, spacing, pests and companion planting, see the full broccoli growing guide →