PlantingWindowThe American Planting Almanac

When to plant borage in Madison, Wisconsin

May 1 – May 15

Direct-sow 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. Direct-sow borage 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 season≈ 161 daysmedian at 32°F
Hard freeze, 28°Apr 20 – Oct 20kills even hardy greens
USDA zone5b-15 to -10°F winter low — not frost timing

The Madison year

Start seeds indoorsMar 20 – Apr 3
Direct-sow outdoorsMay 1 – May 15
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to May 17
Borage in Madison · freeze context from Uw Arboretum - Madison, WI, 1991–2020 normals.

Every method, with its sources

Start seeds indoors

Mar 20 – Apr 3

Illinois Extension permits starting borage indoors but gives no lead time, so the offset comes from Virginia Cooperative Extension's herb publication — whose annual herb table lists borage — which sows small herb seed about six weeks before the last frost date. Anchored to the median last spring freeze (May 1). Virginia Cooperative Extension, Virginia Tech

Direct-sow outdoors

May 1 – May 15

Illinois Extension sows borage directly in the garden after frost is past, a point rule that opens a two-week sowing span at the last spring freeze. Anchored to the median last spring freeze (May 1). University of Illinois Extension · Virginia Cooperative Extension, Virginia Tech

Variety assumption: Virginia Cooperative Extension lists borage as a self-sowing annual; it resents root disturbance, so direct sowing is the usual method.

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 (2)

Keep exploring

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