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What to Plant in March — USDA Zone 5b

Here's everything you can start, transplant, sow, and harvest in March in USDA Zone 5b. This zone has an average last spring frost around April 18 and first fall frost around October 13, with a growing season of approximately 178 days.

There are 5 planting activities for March in Zone 5b.

Zone 5b Moderate season
178 days
Last Spring Frost April 18
178 growing days
First Fall Frost October 13

Where Is Zone 5b?

Direct Sow in March

Plant Type Date Range Days to Maturity
Bachelor's Button Flower 60–90 days
Calendula Flower 50–70 days
Dianthus Flower 60–80 days
Larkspur Flower 60–90 days
Sweet Pea Flower 65–85 days

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: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.