When to plant eggplant in USDA Zone 5a

Plan your eggplant planting around local frost risk and soil temperature, then work backward from the harvest week your buyers need. The calendar below is a starting point, not a field-level weather forecast.

Madison WI, Des Moines, southern MN, central MI. Average last spring frost May 8, first fall frost September 29 — a 144-day frost-free season.

Zone fit: good

Eggplant is frost-tender, so timing the outdoor transplant to the last frost matters more here than in warmer zones. Row cover buys 2 weeks of head start.

Key dates

Start seeds indoors

March 6 – March 20

Transplant outdoors

May 22 – June 12

Expected first harvest

August 17 – September 14

Fall planting window

June 16 – July 7

Fall harvest window

September 11 – October 9

Windows are calculated from your zone's average frost dates. Adjust ±1 week for microclimates, elevation, and your own frost records.

Spacing and soil

Plant spacing: 24″
Row spacing: 36″
Seed depth: 0.25″
Soil temperature: 75–90°F
Frost tolerance: tender
Days to harvest: 80 days

Grower notes for Zone 5a

Flea beetle pressure is highest in early season; use row cover for the first 3 weeks after transplant.

Plant near: beans, peppers, marigolds

Keep away from: fennel

Other nightshades for Zone 5a

Same crop, other zones

Track your own plantings

BAU Farm Intelligence turns these windows into per-field tasks — indoor seed-start reminders, transplant dates, harvest projections — using your farm's actual frost history.

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