When to plant lettuce in USDA Zone 5b

Plan your lettuce 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.

Chicago, Des Moines suburbs, central IL, upstate NY. Average last spring frost May 1, first fall frost October 6 — a 158-day frost-free season.

Zone fit: excellent
Lettuce is well suited to Zone 5b. Standard planting dates work with minor adjustments for microclimates.

Key dates

Start seeds indoors
March 27 – April 10
Direct-seed or transplant outdoors
March 27 – April 17
Expected first harvest
May 18 – June 15
Fall planting window
August 4 – August 25
Fall harvest window
September 25 – October 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
8″
Row spacing
12″
Seed depth
0.125″
Soil temperature
45–70°F
Frost tolerance
half-hardy
Days to harvest
45 days

Grower notes for Zone 5b

Successive plantings every 10–14 days for continuous harvest. Bolts fast above 75°F — use heat-tolerant varieties past May.

Plant near: carrots, radish, strawberries

Other leafy greens for Zone 5b

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.