Blog

What to Plant in March — USDA Zone 4b

Here's everything you can start, transplant, sow, and harvest in March in USDA Zone 4b. This zone has an average last spring frost around May 1 and first fall frost around October 3, with a growing season of approximately 155 days.

Zone 4b Moderate season
155 days
Last Spring Frost May 1
155 growing days
First Fall Frost October 3

Where Is Zone 4b?

There are no planting activities recommended for March in Zone 4b. 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.