USDA Hardiness Zone 3B spans the northern Great Plains and Upper Midwest, with average annual minimum temperatures between -35°F and -30°F. The frost-free growing season runs roughly from May 15 to Sep 15 — about 123 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. For a personalized forecast based on your specific 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.