USDA Hardiness Zone 3B spans the northern Great Plains and Upper Midwest, with average annual minimum temperatures between -35°F and -30°F. Frost-free days run from the last spring frost on Jun 1 to the first fall frost on Sep 8, about 99 days. That is long enough for most warm-season crops if you start seeds indoors 6–10 weeks before transplanting. Wind exposure and rapid temperature swings are common; mulching heavily and choosing wind-tolerant varieties improves yields. Cool-season crops can be succession-planted for extended harvests into early fall. To find your USDA zone by zip code, use our free planting calendar. Browse individual plant guides for detailed growing instructions, or explore how USDA zones work to better understand your growing conditions.
Zone 3B Planting Guide
Last Spring Frost
Jun 1
First Fall Frost
Sep 8
Growing Season
99 days
Filterable list of 100 vegetables, herbs, and flowers for Zone 3B. Each crop links to its plant page for planting dates.
Browse all 100 Zone 3B plant guides →
Jump directly to the detailed growing guide for any plant in Zone 3B.
Vegetables
Herbs
Flowers
Growing guides for Zone 3B
Hand-picked posts from the GardeningByZone blog that apply to your zone.
Printable planting calendar and worksheet
Two PDFs for the Midwest region, to print at home.
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When to plant vegetables outdoors, state by state, from each state's own extension service. IL, IN, IA, MI, MN, MO, OH, WI · Zones 3a through 8a. Printable PDF.
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Lay out beds, plan crop rotation and record planting dates, with a crop reference for the Midwest region. Printable PDF.
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