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. Lemon Balm 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.
Common questions
How long does lemon balm take to grow in zone 6b?
Lemon Balm matures in about 60–90 days from transplanting. In zone 6b that means setting plants out around Apr 19 and first picking around Jun 18.
Will lemon balm survive frost in zone 6b?
Yes — lemon balm 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).
For soil, spacing, pests and companion planting, see the full lemon balm growing guide →