When to plant thyme in zone 5b — planting calendar

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Showing USDA Zone 5B

Growing SeasonZone 5b

Last frost ~May 15First frost ~Sep 30Today

Start indoorsTransplant / sowHarvestFrost risk

MARAPRMAYJUNJULAUGSEPOCT

Start indoors Mar 20 · Transplant May 8 · First harvest Jul 7 · Wrap by Sep 30

Last spring frostMay 15

Start seeds indoorsMar 20

Transplant outMay 8

First harvestJul 7

Last harvestSep 30

First fall frostSep 30

Why these dates work in zone 5b

Zone 5b's last spring frost averages May 15 and first fall frost Sep 30 — about 138 frost-free days. Thyme 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 8 weeks ahead gives strong transplants ready the moment the soil warms.

Common questions

How long does thyme take to grow in zone 5b?

Thyme matures in about 60–90 days from transplanting. In zone 5b that means setting plants out around May 8 and first picking around Jul 7.

Will thyme survive frost in zone 5b?

Yes — thyme tolerates light frost. In zone 5b you can set plants out a little before the last frost (around May 15) and keep harvesting past the first fall frost (around Sep 30).

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