When to plant rosemary in zone 6b — planting calendar

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Showing USDA Zone 6B

Growing SeasonZone 6b

Last frost ~Apr 20First frost ~Oct 15Today

Start indoorsTransplant / sowHarvestFrost risk

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Start indoors Feb 9 · Transplant Apr 20 · First harvest Jul 9 · Wrap by Oct 8

Last spring frostApr 20

Start seeds indoorsFeb 9

Transplant outApr 20

First harvestJul 9

Last harvestOct 8

First fall frostOct 15

Why these dates work in zone 6b

Zone 6b's last spring frost averages Apr 20 and first fall frost Oct 15 — about 178 frost-free days. Rosemary 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 10 weeks ahead gives strong transplants ready the moment the soil warms.

Common questions

How long does rosemary take to grow in zone 6b?

Rosemary matures in about 80–100 days from transplanting. In zone 6b that means setting plants out around Apr 20 and first picking around Jul 9.

Will rosemary survive frost in zone 6b?

No — rosemary is frost-sensitive. In zone 6b, wait until after the last frost (around Apr 20) to plant, and harvest before the first fall frost (around Oct 15).

For soil, spacing, pests and companion planting, see the full rosemary growing guide →