When to plant swiss chard in USDA Zone 3b

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.

Grand Forks & Minot ND, northern MN border counties. Average last spring frost May 25, first fall frost September 10 — a 108-day frost-free season.

Zone fit: excellent
Swiss chard is well suited to Zone 3b. Standard planting dates work with minor adjustments for microclimates.

Key dates

Start seeds indoors
April 20 – May 4
Direct-seed or transplant outdoors
April 27 – May 18
Expected first harvest
June 28 – July 26
Fall planting window
June 25 – July 16
Fall harvest window
August 26 – September 23

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 3b

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 3b

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.