Growing romanesco in zone 9a

(Zone 9a = an average winter low of 20°F to 25°F.)

In USDA zone 9a, the typical last spring frost is March 2 and the first fall frost is November 26. Here is when to plant romanesco against those dates.

Start seeds indoorsJanuary 19 to February 2

Transplant outdoorsMarch 2

Expected harvestMay 16 to June 10About 75 to 100 days from transplanting.

These are zone 9a averages

Computed from 2,196 ZIP codes in zone 9a. 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 romanesco from University of Wisconsin-Madison Division of Extension. Zone dates are medians; local conditions vary.