sweet corn (Zea mays), photographi

Can I Grow Sweet Corn in Wisconsin?

USDA Zones 3b-6a · Plant zone range 2-11

Yes — Strong Match

sweet corn (zones 2-11) covers every zone Wisconsin contains (3b-6a), so hardiness is not what limits it anywhere in the state.

Sweet Corn in Wisconsin — the short answer

Sweet Corn in Wisconsin: hardy in zones 2–11, full sun, against a state median of ~173 frost-free days.

Plant zones
2-11
Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
Wisconsin zones
3b-6a
USDA PHZM 2023
Frost window
Apr 17 - May 2 – Oct 9 - Oct 21
NOAA RCC ACIS 1991-2020, 28°F
Shortest county season
140 days
NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
Days to maturity
80 days
Growable Ground Plant Database

Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.

Score your parcel · free

Your yard isn't the whole zone.

Sweet Corn is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Wisconsin site runs ~173 frost-free days, but that is a state median, not your yard: slope, trees, and low spots move the last-frost date across a single parcel. Enter your address and we'll score sweet corn against your land's actual frost dates, sun, and soil.

We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.

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Wisconsin is not one climate

A single Wisconsin answer averages 72 counties whose growing seasons are 77 days apart — from 140 frost-free days in Florence County to 217 in Milwaukee County. Which end of that your land sits nearer changes what sweet corn can finish before the first hard freeze.

140 daysFlorence County217 daysMilwaukee County

The middle half of 72 counties runs 158187 days, with a median of 173 days — a 77-day span end to end.

Measured across 72 Wisconsin counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.

Where in Wisconsin Fits Best

Even within Wisconsin's zones 3b-6a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for sweet corn (USDA PHZM 2023):

Zone Comparison

Sweet Corn Needs

  • USDA Zones: 2-11
  • Frost-Free Days: 65+
  • Sun: Full Sun
  • Mature size: 8 ft tall
  • Picking window: ~10 days of harvest
  • Drought tolerance: Low

Wisconsin Has

  • USDA Zones: 3b-6a
  • Last Hard Freeze (28°F): Apr 17 - May 2
  • First Hard Freeze (28°F): Oct 9 - Oct 21
  • Annual Rainfall: 28-34 inches
  • Common Soils: Silt loam, Clay loam, Sandy outwash

Plant Zone Range (zones 2-11)

2a
11b
3a (Cold)13b (Hot)

Preferred Soil pH

3.5 (Acidic)7.0 (Neutral)9.0 (Alkaline)
Highlighted range: pH 4.58.5

Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.

When to Plant Sweet Corn in Wisconsin

The frost window

Across Wisconsin, the last spring hard freeze (28°F) clears between Apr 17 and May 2, and the first fall hard freeze lands between Oct 9 and Oct 21 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 160-day window you can count on — up to 187 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.

When to start the seed

Sweet Corn is direct-sown where it grows rather than started under cover, so there is no seed-tray head start to bank — Wisconsin's dates above are the whole calendar for it. That makes the last-freeze date the binding constraint, and a warmer pocket of your own yard is worth more to this crop than it is to a transplanted one.

Days to maturity vs. the window

At 80 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 80 days to spare even in Wisconsin's tightest freeze scenario — room for a later start or a second sowing.

Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.

Growing Season Fit

The zone check says sweet corn survives winter here. Whether the season is long enough — and warm enough — is a different question.

Frost-free days

Sweet Corn wants 65+ frost-free days; a typical Wisconsin site sees ~173 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.

Growing degree days

Sweet Corn needs ~2000 GDD (base 50°F) to ripen. The state median runs ~2102 GDD (from PRISM 1991-2020 climate normals), so Wisconsin sits right at the threshold — pay attention to siting and microclimate.

GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.

Soil + Drainage Fit

Sweet Corn tolerates a wide pH range (pH 4.5-8.5) — 4 units, acid ground through alkaline — so soil acidity is rarely what limits it in Wisconsin. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. It will grow across that whole span, but it does best between pH 5 and 7 — worth knowing before you decide whether a Wisconsin soil test result is a problem or just a number.

Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. Wisconsin soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.

Before you plant sweet corn for food

Anything you grow to eat takes up what is in the ground it grows in, so what is on record near you is worth knowing before sweet corn goes in. What follows is Wisconsin’s documented federal record at state scale — a screening signal, not a soil test, and not a statement about any one lot.

Safe to Grow Here?

What the federal record shows across Wisconsin — and how to grow with it.

Federal record: High

We checked the federal record across Wisconsin57,912 documented sites across 8 of the 9 source types we track.

The most significant on record: 314 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.

Wisconsin carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.

Severity Distribution

across Wisconsin

High909Moderate13,703Low43,300

Highest-Severity Sites

4s and B Mine
Mining Sites · Unknown
Algoma Municipal Landfill
Superfund · Superfund NPL
Amcast Industrial Corporation
Superfund · Superfund NPL
Appleton Waterworks
PFAS Sampling · PFAS Detected
Ashland/Northern States Power Lakefront
Superfund · Superfund NPL

Know Before You Grow

  • Underground tanks leak petroleum as they age — near a former filling station, test the soil.
  • Near a brownfield, raised beds of imported soil give your food clean ground.
  • On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.

Sources: EPA, USGS1.8M documented sites tracked nationwide across 9 federal source types.

What Else to Consider for Sweet Corn in Wisconsin

Zone compatibility tells you about winter cold survival — but Wisconsin growers also need to think about:

Cold winters (-30F in northern WI)

Short growing season (110-140 frost-free days)

Sandy central soils drain too quickly

What to actually do about these — and the constraints that apply to every Wisconsin grower, not just sweet corn — is covered on the Wisconsin growing guide.

Timing shifts within Wisconsin

Sweet Corn needs about 65 days of frost-free season to complete its cycle. Even Florence County — Wisconsin’s shortest season at 140 frost-free days — clears that by 75 days, so season length isn’t the constraint anywhere in Wisconsin. What varies is your own parcel.

Across Wisconsin’s 72 counties the frost-free season runs from 140 days in Florence County to 217 days in Milwaukee County — a spread of 77 days, which is why a single statewide planting date misleads. The median Wisconsin county sees 173 frost-free days, leaving sweet corn about 108 days of slack on a typical parcel — room for a second sowing where the season runs long.

County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Sweet Corn's 65-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.

Wisconsin Cooperative Extension

For Wisconsin-specific cultivar recommendations, planting calendars, and pest pressure for sweet corn, the canonical source is UW–Madison Division of Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.

Is Sweet Corn native to Wisconsin?

No — the USDA PLANTS Database lists Sweet Corn as introduced rather than native in the Lower 48, so it is not part of Wisconsin's native flora. It grows here as a garden plant; pairing it with a few Wisconsin natives keeps local pollinators fed too.

Looking for plants that belong here? The Wisconsin growing guide lists USDA-documented natives for the state.

Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.

What pests threaten sweet corn in Wisconsin?

Japanese beetle is documented in Wisconsin and will find sweet corn, but it is manageable here. What an experienced grower watches for, and does:

Japanese beetle

Japanese beetle

Worth watching

This is on the University of Minnesota's list of Japanese beetle preferred plants — but their read is that fruits, vegetables and herbs tolerate limited leaf feeding, and that in most cases the damage is cosmetic and will not kill the plant.

What to do: Protect it only through the few peak weeks: handpick into soapy water in the cool of morning, harvest regularly through July and August to take the feeding pressure off the edible parts, and keep the plant well watered — a vigorous plant outgrows feeding that looks worse than it is. Do not hang a beetle trap.

Documented range: states listed as Japanese-beetle infested · University of Minnesota Extension, National Plant Board

The full japanese beetle playbook

Only pests whose documented range and host relationship both trace to a primary source appear here — so a quiet section means we have nothing sourced to tell you, not that your garden is pest-free.

Common Questions About Growing Sweet Corn in Wisconsin

When can I plant Sweet Corn in Wisconsin?

Wisconsin's last spring hard freeze (28°F) clears between Apr 17 and May 2, and the first fall hard freeze lands between Oct 9 and Oct 21 (NOAA Regional Climate Centers ACIS, 1991-2020). Time outdoor planting to after the last hard freeze for your specific site — a further two to three weeks for anything tender — and count back from those dates for transplant scheduling.

Can Sweet Corn mature before first frost in Wisconsin?

Yes — Sweet Corn matures in 80 days (Growable Ground Plant Database), and Wisconsin's dependable hard-freeze-free window runs 160 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 80 days of margin. Plant once the last hard freeze has passed — two to three weeks later for anything tender — and it ripens ahead of the first fall freeze.

What hardiness zone is Sweet Corn grown in across Wisconsin?

Wisconsin spans USDA hardiness zones 3b-6a (USDA ARS PHZM 2023). Sweet Corn carries a range of zones 2-11, so the overlap zones are where outdoor growing is most reliable.

How many frost-free days does a typical Wisconsin site have?

A typical Wisconsin site sees ~173 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Sweet Corn needs 65+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.

Is Sweet Corn native to Wisconsin?

No — the USDA PLANTS Database lists Sweet Corn as introduced rather than native in the Lower 48, so it is not part of Wisconsin's native flora. It grows here as a garden plant; pairing it with a few Wisconsin natives keeps local pollinators fed too.

How should I amend the soil for Sweet Corn in Wisconsin?

Sweet Corn tolerates pH 4.5-8.5 (FAO ECOCROP). That is a 4-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Wisconsin site — amend for drainage and organic matter first.

Will Sweet Corn actually grow on my specific land in Wisconsin?

State-level zone + climate data is a sketch. A Growable Ground parcel report scores sweet corn against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.

Free Report

Check your specific parcel in Wisconsin

State-level data is a sketch. Your Growable Ground report scores sweet corn against your parcel's exact soil, sun, drainage, and frost data — not zone averages.

Three things about your lot that Wisconsin sweet corn averages can't show:

Your soil pHYour frost-free days — Wisconsin averages 173Your sun & shade

We read public map data around Wisconsin — soil, climate, flood, and parcel records. How we handle your address.

25+ data sources read at your address, not the Wisconsin sweet corn average

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