When to plant swiss chard in Milwaukee, Wisconsin
April 12 – April 26
Direct-sow outdoors · typical Milwaukee yearClimate basis: NOAA station West Allis, WI (USC00479046), 6 mi (10 km) from downtown Milwaukee (ZCTA 53202 centroid), elevation 723 ft, on the 1991–2020 climate normals. Direct-sow swiss chard from approximately the dates above, anchored to the median last spring 32°F freeze (April 26). One year in ten still freezes after May 12.
The Milwaukee year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to May 12
Every method, with its sources
Direct-sow outdoors
Apr 12 – Apr 26Purdue: semi-hardy — 2–4 weeks before the last frost; Penn State's earliest sowing Apr 17 (−14 days) is the later start and is used. Anchored to the median last spring freeze (Apr 26). Penn State Extension (York County Master Gardeners) · Purdue University Extension
Start seeds indoors
Not calculatedThe cited extension guides do not time an indoor seed-starting window for this crop.
Transplant outdoors
Not calculatedThe cited extension guides do not time an outdoor transplanting window for this crop.
Fall planting
Not calculatedNo source-backed fall planting rule exists for this crop in the registry, so no fall window is calculated.
Variety assumption: First cutting about 50–60 days from seed (Penn State lists 55); tolerates summer heat better than spinach.
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.
Crop rule sources (2)
- Penn State Extension (York County Master Gardeners): Vegetable Seed Planting Guide (accessed 2026-07-24)Earliest/latest sowing dates for a May 1 last-frost / Oct 1 first-frost baseline; offsets derived by date difference from May 1. Also days-to-maturity figures.
- 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.