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What to Plant in March — USDA Zone 3b

Here's everything you can start, transplant, sow, and harvest in March in USDA Zone 3b. This zone has an average last spring frost around May 10 and first fall frost around September 22, with a growing season of approximately 135 days.

Zone 3b Short season
135 days
Last Spring Frost May 10
135 growing days
First Fall Frost September 22

Where Is Zone 3b?

There are no planting activities recommended for March in Zone 3b. Check nearby months for planting windows.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Planting dates are estimates based on average frost dates — local conditions may vary. Last updated: April 2026.