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Wisconsin planting calendar

When to plant potatoes in Wisconsin — sow, transplant & harvest dates

Wisconsin is mostly USDA zone 5a (range 3b-6a). Dates below are derived from potatoes's frost tolerance and Wisconsin's frost window — not generic national averages.

Potatoes planting timetable for Wisconsin

StageWhen in WisconsinAnchor
Direct-sow outsidelate April (April 24)21 days before the last frost (mid-May)
First harvest (estimate)mid-July (July 18)~85 days from direct sow

Dates are state-wide averages for the dominant zone. Local microclimates — elevation, urban heat, coastal moderation — can shift the window by 1-2 weeks. Use the frost-date calculator for a date tuned to your town.

Why Wisconsin's climate shifts the potatoes dates

Wisconsin's last spring frost averages mid-May and first fall frost early October, which sets the whole planting clock. Wisconsin is a cold, continental Midwest state, milder along Lake Michigan and considerably colder in the northern interior. Sow early — potatoes bolt once daytime temperatures hold above 24 °C, so the earlier they go in, the longer the harvest.

Potatoes are planted as certified seed potatoes (not supermarket tubers) 2-4 weeks before the last spring frost, once soil temperature reaches at least 7 °C; they tolerate light frost in the ground but emerging foliage is killed below -2 °C, so hill soil over any shoots that break through during a late freeze. In zones 9-11 potatoes are a winter or early-spring crop, planted in late January-February to mature before summer heat forces them dormant. Days-to-harvest ranges from 70 days for early/new-potato types to 110-120 days for maincrop storage varieties.

Frost-risk note

Don't plant before mid-May — a hard freeze can still set young plants back. In the north-central highlands near the UP line (zone 3b) the safe date runs a week or two later.

Regional variation within Wisconsin

the north-central highlands near the UP line (zone 3b) runs roughly 1-2 weeks behind the state average; the Lake Michigan shore around Milwaukee (zone 6a) can plant 1-2 weeks earlier.

What else to plant in Wisconsin around then

The same early window suits peas, lettuce, spinach, and onion sets.

Quick-grow guide

Frequently asked questions

When is the best time to plant potatoes in Wisconsin?

In Wisconsin (mostly USDA zone 5a), direct-sow potatoes late April (before the last frost, mid-May), and harvest from mid-July. Potatoes are half-hardy — young plants shrug off a light frost but not a hard freeze, so sowing can start a couple of weeks before the last spring frost.

What USDA zone is Wisconsin?

Most of Wisconsin sits in USDA hardiness zone 5a, with the state spanning roughly 3b-6a from the north-central highlands near the UP line (zone 3b) to the Lake Michigan shore around Milwaukee (zone 6a). The last spring frost averages mid-May and the first fall frost early October.

Can you grow potatoes in Wisconsin?

Yes. Wisconsin's dominant zone 5a supports potatoes — the key is timing. Potatoes are half-hardy — young plants shrug off a light frost but not a hard freeze, so sowing can start a couple of weeks before the last spring frost.

Does the planting date change across Wisconsin?

the north-central highlands near the UP line (zone 3b) runs roughly 1-2 weeks behind the state average; the Lake Michigan shore around Milwaukee (zone 6a) can plant 1-2 weeks earlier.

What else can I plant in Wisconsin around the same time?

The same early window suits peas, lettuce, spinach, and onion sets.

Source and methodology

State zone spans from the USDA Plant Hardiness Zone Map (2023); frost-date averages from NOAA Climate Data Online. Hot-state two-season timing cross-checked against the UF/IFAS Florida Gardening Calendar and the University of Arizona Cooperative Extension planting calendar. Curated by the Growli editorial team.

Keep going

Same crop, nearby states (Midwest)

Other crops for Wisconsin