When to Plant Eggplant in Wisconsin
Beautiful purple fruits that love heat even more than tomatoes. Start early indoors for best results.
The Short Answer
Wisconsin Frost Dates
Your planting dates depend on which part of Wisconsin you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Northern Wisconsin | 3b, 4a | May 15 - Jun 1 | Sep 10 - Sep 25 |
| Central Wisconsin | 4a, 4b | May 5 - May 20 | Sep 20 - Oct 5 |
| Southern Wisconsin | 4b, 5a, 5b | Apr 25 - May 10 | Oct 1 - Oct 15 |
Eggplant Planting Schedule for Wisconsin
Northern Wisconsin (Zones 3b, 4a)
Average last frost: May 15 - Jun 1 · Average first frost: Sep 10 - Sep 25
Central Wisconsin (Zones 4a, 4b)
Average last frost: May 5 - May 20 · Average first frost: Sep 20 - Oct 5
Southern Wisconsin (Zones 4b, 5a, 5b)
Average last frost: Apr 25 - May 10 · Average first frost: Oct 1 - Oct 15
Growing Eggplant in Wisconsin
Eggplant in Wisconsin's Climate
Eggplant is one of the trickiest warm-season crops for cold climates — it demands even more heat than peppers. Asian varieties (Ichiban, Orient Express, 55-58 days) are the only reliable choice. Start indoors 10 weeks before last frost. Black plastic mulch and row cover are both necessary. Container growing on sun-baked pavement sometimes outproduces in-ground planting.
Soil Considerations for Wisconsin
Rich agricultural soils in southern half. Sandy soils in central plain. Heavy clay in some lake regions. Generally fertile. Make sure soil has warmed to at least 70°F before planting eggplant outside.
Wisconsin Climate & Growing Season
Cold winters. Warm summers. Lake Michigan moderates eastern climate. Good growing season in south. Short season in north. Eggplant cannot tolerate any frost, so wait until all frost danger has passed before transplanting outside. Watch local forecasts carefully in spring.
Growing season length varies across Wisconsin: Northern Wisconsin (3b, 4a) has a last frost around May 15 - Jun 1, while Southern Wisconsin (4b, 5a, 5b) sees frost end around Apr 25 - May 10. This difference matters for eggplant — transplant timing shifts by several weeks across the state.
Growing Tips
Harvest when skin is glossy and firm. Dull skin means overripe and seedy. Use row covers if nights are cool.
Companion Planting
Plant eggplant alongside these companions for better growth:
Keep eggplant away from:
The Bottom Line
Last reviewed: March 29, 2026