When to plant swiss chard in USDA Zone 4a

Plan your swiss chard 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.

Fargo ND, northern MN, northern WI, northern ME. Average last spring frost May 22, first fall frost September 15 — a 116-day frost-free season.

Zone fit: excellent
Swiss chard is well suited to Zone 4a. Standard planting dates work with minor adjustments for microclimates.

Key dates

Start seeds indoors
April 17 – May 1
Direct-seed or transplant outdoors
April 24 – May 15
Expected first harvest
June 25 – July 23
Fall planting window
June 30 – July 21
Fall harvest window
August 31 – September 28

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
10″
Row spacing
18″
Seed depth
0.5″
Soil temperature
50–75°F
Frost tolerance
hardy
Days to harvest
55 days

Grower notes for Zone 4a

Cut-and-come-again crop. A spring planting can produce well into fall with cool weather and consistent water.

Plant near: beans, onions

Keep away from: corn

Other leafy greens for Zone 4a

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.