When to plant thyme in Madison, Wisconsin

May 1 – May 15

Transplant outdoors · typical Madison year

Climate basis: NOAA station Uw Arboretum - Madison, WI (USC00470273), 4 mi (6 km) from downtown Madison (ZCTA 53703 centroid), elevation 870 ft, on the 1991–2020 climate normals. Transplant thyme outdoors from approximately the dates above, anchored to the median last spring 32°F freeze (May 1). One year in ten still freezes after May 17.

Last spring freezeMay 11-in-10 after May 17
First fall freezeOctober 91-in-10 before Sep 26
Frost-free season161 daysmedian at 32°F
Hard freeze, 28°Apr 20Oct 20kills even hardy greens
USDA zone5b-15 to -10°F winter low not frost timing

The Madison year

Transplant outdoorsMay 1 – May 15
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to May 17
Thyme in Madison · freeze context from Uw Arboretum - Madison, WI, 1991–2020 normals.

Every method, with its sources

Transplant outdoors

May 1 – May 15

Oklahoma State Table 1: plant thyme after the last spring frost (seed or cuttings; most gardeners set out plants). Point rule given a 14-day span. Anchored to the median last spring freeze (May 1). Oklahoma State University Extension

Start seeds indoors

Not calculated

The cited guide gives no indoor seed-starting lead time for thyme, so no window is calculated.

Direct-sow outdoors

Not calculated

The cited extension guides do not time direct sowing for this crop.

Fall planting

Not calculated

No source-backed fall planting rule exists for this crop in the registry, so no fall window is calculated.

Variety assumption: A hardy perennial once established; harvest lightly the first season.

These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.

This week, not a typical year:
Crop rule sources (1)

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