When to plant brussels sprouts in USDA Zone 5a

Plan your brussels sprouts 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: challenging
Brussels sprouts needs a long season and this zone averages just 144 frost-free days. Start early, use black plastic, and plan for row cover on shoulder-season frosts.

Key dates

Start seeds indoors
March 20 – April 3
Transplant outdoors
April 17 – May 8
Expected first harvest
August 2 – August 30
Fall planting window
May 19 – June 9
Fall harvest window
September 3 – October 1

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
55–75°F
Frost tolerance
hardy
Days to harvest
100 days

Grower notes for Zone 5a

Fall-only crop in the Southeast. Top the plant 4 weeks before target harvest for uniform sprouts up the stem.

Plant near: onions, dill

Keep away from: strawberries

Other brassicas 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.