When to plant basil 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

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Start indoors Apr 17 · Sow May 29 · First harvest Jun 23 · Wrap by Sep 15

Last spring frostMay 15

Start seeds indoorsApr 17

Direct sowMay 29

First harvestJun 23

Last harvestSep 15

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. Basil is frost-sensitive, so the 2w after 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 4 weeks ahead gives strong transplants ready the moment the soil warms.

Common questions

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

Basil matures in about 25–35 days from sowing. In zone 5b that means sowing around May 29 and first picking around Jun 23.

Will basil survive frost in zone 5b?

No — basil is frost-sensitive. In zone 5b, wait until after the last frost (around May 15) to plant, and harvest before the first fall frost (around Sep 30).

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