Lawn & Garden • Wisconsin Planting Dates • Updated October 29, 2026

When to Plant Tomatoes in Wisconsin: Dates, Soil Temps and Tips

Explore related guides: When to start seeds in Wisconsin · Tomatoes in Minnesota · Tomatoes in Illinois · Tomatoes in Iowa · Tomatoes in Nebraska.

Tomatoes are the most common crop in Wisconsin gardens, and the biggest mistake is planting them too soon. Even without a frost, nights below 50°F can injure heat-loving tomatoes and stall them for weeks. This guide explains when to plant tomatoes in Wisconsin, region by region, using UW–Madison Extension guidance on dates, soil temperature and the best early varieties for a short season.

When to plant tomatoes in Wisconsin: the short answer

In southern Wisconsin, UW Extension suggests planting tomatoes out around May 15 to 20. In west-central Wisconsin, Memorial Day is the usual target. Central Wisconsin and the lower Lake Michigan shore typically plant one to two weeks after Madison, northern counties two to three weeks later, and the Lake Superior clay plain as late as the last week of June. In every region, wait for soil of at least 60°F and nights that stay above 50°F.

Tomato planting dates by region

Freeze dates are 1991 to 2020 averages from the Wisconsin State Climatology Office. Start seeds indoors 6 to 8 weeks before your planting date; see our Wisconsin seed starting calendar.

Soil temperature and night temperature

• Soil at least 60°F. UW Extension advises not planting tomatoes and peppers until soil reaches at least 60°F; cold soil stunts transplants. An inexpensive soil thermometer helps.
• Nights above 50°F. Temperatures below 50°F can cause cold injury to heat-loving crops even when nights never reach freezing.
• Use season extenders. Water-filled plant protectors, cold frames and frost cloth let you plant a little earlier and protect plants on cold nights.
• Watch the forecast for the 10 days after planting; spring weather in Wisconsin is fickle.

Early tomato varieties for Wisconsin’s short season

UW Extension notes that tomatoes are a long-season crop, so gardeners in northern Wisconsin should choose cultivars that mature in fewer days. Its Homegrown Tomatoes for Wisconsin publication lists these early options:

Growing several varieties with different maturity dates spreads out the harvest and protects against disease.

How to plant tomatoes in Wisconsin

1. Harden off plants for 7 to 10 days, wheeling them outside on mild days and back in before cold nights.
2. Check soil temperature a few inches deep in the morning before planting.
3. Plant on a calm, cloudy day or in late afternoon.
4. Bury the stem deep; tomatoes root along the buried stem.
5. Stake, cage or trellis now. UW Extension strongly recommends support for indeterminate tomatoes to maximize harvest and reduce disease.
6. Water deeply and evenly, and mulch once the soil has warmed.

Tools for planting tomatoes

All five were listed as sold by Amazon.com when checked on October 29, 2026. Check the current listing before you buy.

To know when soil is ready: Taylor Soil Thermometer

The simple tool UW Extension suggests for timing warm-season planting: a stainless steel probe that shows when soil reaches the 60°F tomatoes need.

For a late cold snap: Amazon Basics Plant Covers, 10 x 30 ft

A breathable frost cloth for the cold nights that can still arrive in late May and June in central and northern Wisconsin.

For support: Happygrill Adjustable Tomato Cages, 60 in, 3 Pack

Tall, adjustable cages for the support UW Extension strongly recommends for indeterminate tomatoes.

For tying to stakes: VELCRO Brand Adjustable Plant Ties, 75 ft

Soft, reusable ties that hold stems to stakes without cutting into them.

For steady watering: Gilmour 50 ft Flat Soaker Hose

A flat soaker hose that waters the roots and keeps leaves dry, helping to reduce leaf disease and blossom end rot.

Conclusion

Plant tomatoes in Wisconsin around May 15 to 20 in the south, Memorial Day in west-central Wisconsin, late May to mid-June in central and northern counties, and as late as the end of June near Lake Superior. Wait for 60°F soil and nights above 50°F, pick early varieties up north, and support plants from day one.

FAQs

When should I plant tomatoes in Madison?
Around May 15 to 20, once soil has reached about 60°F and nights stay above 50°F.

When should I plant tomatoes in Green Bay?
Typically late May to early June, one to two weeks later than Madison, as UW Extension suggests for central Wisconsin and the lower Lake Michigan shore.

When should I plant tomatoes in northern Wisconsin?
Two to three weeks later than southern Wisconsin, usually early to mid-June, and as late as the last week of June along the Lake Superior clay plain.

What soil temperature do tomatoes need?
At least 60°F. Cold soil can stunt plants and slow their growth for weeks.

What are the best early tomatoes for Wisconsin?
UW Extension lists Sub-Arctic Plenty (45 days), Early Girl (54 days), Quick Pick and Early Cascade (60 days) and Mountain Spring (65 days).

Can cold nights hurt tomatoes without a frost?
Yes. Temperatures below 50°F can cause cold injury to heat-loving crops like tomatoes even if it never freezes.

Sources and review scope

This guide was prepared on October 29, 2026 from the following sources and from the product listings on Amazon.com. Homingwell did not perform hands-on testing.

• UW–Madison Extension – Homegrown tomatoes for Wisconsin (A1691)
• UW–Madison Extension (Kenosha County) – Timing of seeding in Wisconsin
• Wisconsin Public Radio with UW Extension – Starting a successful vegetable garden
• Wisconsin State Climatology Office – Average last spring freeze dates
• Milwaukee Journal Sentinel – Early planting pluses and minuses

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