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Sprout Authority

Growing petunia in zone 3a

In USDA zone 3a, the typical last spring frost is May 29 and the first fall frost is September 5. Here is when to plant petunia against those dates.

Start seeds indoorsMarch 20 to April 3
Transplant outdoorsMay 29 to June 12

These are zone 3a averages

Computed from 17 ZIP codes in zone 3a. Your town's frost dates vary; enter your ZIP for dates built on your nearest weather station.

Get my exact dates

USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service / Oregon State University PRISM Group. NOAA National Centers for Environmental Information, U.S. Climate Normals 1991-2020. Planting windows for petunia from Clemson Cooperative Extension, Home & Garden Information Center. Zone dates are medians; local conditions vary.