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Sprout Authority

Growing fennel in zone 4b

(Zone 4b = an average winter low of -25°F to -20°F.)

In USDA zone 4b, the typical last spring frost is May 8 and the first fall frost is October 1. Here is when to plant fennel against those dates.

Start seeds indoorsMarch 27 to April 10
Direct sow outdoorsMay 8
Expected harvestJuly 7 to August 6About 60 to 90 days from sowing.

These are zone 4b averages

Computed from 1,251 ZIP codes in zone 4b. 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 fennel from Utah State University Extension. Zone dates are medians; local conditions vary.