Zone 3b monthly plan

March planting calendar for zone 3b

These actions use zone 3b's typical frost dates and each crop's extension-sourced planting window.

Last spring frost: May 17
First fall frost: September 23
Exact actions: 25

Get dates for your exact ZIP

Zone averages cover wide areas. Your nearest NOAA station gives a more local frost window.

Exact March dates

Source-backed actions

Your March checklist

Search a crop or narrow the list by garden action. Dates are shifted from zone 3b's typical frost window.

Showing 5 of 25 matching actions

Start indoors

Ageratum
flower
March 8 to March 22SourceUniversity of Wisconsin-Madison Division of Extension (Wisconsin Horticulture)
Annual Salvia (Scarlet Sage)
flower
March 22 to April 5SourceClemson Cooperative Extension, Home & Garden Information Center
Bachelors Button
flower
March 22 to April 5SourceNorth Carolina Extension Gardener Plant Toolbox (NC State Extension)
Basil
herb
March 22 to April 5SourceUniversity of Minnesota Extension
Broccoli
vegetable
March 8 to March 22SourceUtah State University Extension

How this checklist is sourced

USDA defines the hardiness zone, NOAA normals provide the typical frost anchors, and each crop's extension source supplies the planting offset. Broad season-only notes are kept on plant profiles because they do not change from one zone page to another.

USDA Plant Hardiness Zone Map, 2023 by USDA Agricultural Research Service / Oregon State University PRISM Group. the USDA hardiness-zone band.
U.S. Climate Normals 1991-2020 by NOAA National Centers for Environmental Information. the median spring and fall freeze dates.

Local conditions vary.