Growing bok choy in zone 4a

(Zone 4a = an average winter low of -30°F to -25°F.)

In USDA zone 4a, the typical last spring frost is May 12 and the first fall frost is September 28. Here is when to plant bok choy against those 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 bok choy from Cornell University Home Gardening. Zone dates are medians; local conditions vary.