When to plant sweet corn in Burlington, Vermont

May 13 – May 27

Direct-sow outdoors · typical Burlington year

Climate basis: NOAA station Burlington INTL AP, VT (USW00014742), 3 mi (5 km) from downtown Burlington (ZCTA 05401 centroid), elevation 330 ft, on the 1991–2020 climate normals. Direct-sow sweet corn from approximately the dates above, anchored to the median last spring 32°F freeze (April 29). One year in ten still freezes after May 11.

Last spring freezeApril 291-in-10 after May 11

First fall freezeOctober 151-in-10 before Oct 2

Frost-free season≈ 169 daysmedian at 32°F

Hard freeze, 28°Apr 18 – Oct 28kills even hardy greens

USDA zone5b-15 to -10°F winter low — not frost timing

The Burlington year

Direct-sow outdoorsMay 13 – May 27

indoors under lights
in the garden
frost-free season
1-in-10 years still freeze to May 11

Sweet corn in Burlington · freeze context from Burlington INTL AP, VT, 1991–2020 normals.

Every method, with its sources

Direct-sow outdoors

May 13 – May 27

UGA: wait until at least two weeks after the last average killing frost. Purdue lists corn as tender (after last frost) and UNH keys sowing to 60°F soil; the later UGA rule is used. Anchored to the median last spring freeze (Apr 29). University of Georgia Cooperative Extension · Purdue University Extension · University of New Hampshire Extension

Start seeds indoors

Not calculated

The cited guides time sweet corn by direct seeding only.

Transplant outdoors

Not calculated

The cited extension guides do not time an outdoor transplanting window 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: Assumes a mid-season hybrid (about 70–85 days; Penn State lists 80).

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 (3)

University of Georgia Cooperative Extension: Growing Home Garden Sweet Corn (Circular 905) (accessed 2026-07-24)
"Wait until at least two weeks after the last average killing frost before planting."
Purdue University Extension: Indiana Vegetable Planting Calendar (HO-186-W) (accessed 2026-07-24)
Hardiness classes: hardy = plant 4-6 wk before last spring frost; semi-hardy = 2-4 wk before; tender = after average last frost; very tender = at least 2 wk after. Table 2: fall planting at least 4-8 wk before first fall frost.
University of New Hampshire Extension: Growing Vegetables: When to Plant Your Vegetable Garden [fact sheet] (accessed 2026-07-24)
Per-crop 'time from seed to transplant' and 'safe to set out in garden' relative to last frost.

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