Growing romanesco in zone 5a
(Zone 5a = an average winter low of -20°F to -15°F.)
In USDA zone 5a, the typical last spring frost is May 3 and the first fall frost is October 5. Here is when to plant romanesco against those dates.
Start seeds indoorsMarch 22 to April 5
Transplant outdoorsMay 3
Expected harvestJuly 17 to August 11About 75 to 100 days from transplanting.
These are zone 5a averages
Computed from 2,383 ZIP codes in zone 5a. Your town's frost dates vary; enter your ZIP for dates built on your nearest weather station.
Get my exact datesUSDA 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 romanesco from University of Wisconsin-Madison Division of Extension. Zone dates are medians; local conditions vary.