Growing Calendar

MenuClose

HomeAboutSearch

When to plant broccoli in zone 4a

In zone 4a, where the last spring frost typically comes around May 13, start broccoli indoors February 25 to March 18 and plant out April 15 to 29. For a fall crop, plant July 13 to August 10.

The zone 4a schedule for broccoli

Start seeds indoors
February 25 to March 18
Plant out
April 15 to 29
Sow outdoors
April 22 to 29
First harvest, roughly
June 4 to July 13
Plant for a fall crop
July 13 to August 10

From the median frost dates of the NOAA stations assigned to the 739 ZIP codes in zone 4a, and the timing recommended by Cooperative Extension guides for broccoli.

Dates before the last frost assume the soil has thawed and is dry enough to work: a squeezed handful crumbles instead of sticking. After a late or wet spring, wait for that even if the date has passed.

Frost risk in zone 4a

Zones are based on winter cold, not on frost dates, so the last spring frost varies a lot within a zone. Across zone 4a, the typical last frost ranges from about May 6 in the earliest tenth of ZIP codes to May 24 in the latest tenth, and the first fall frost from September 20 to October 3. For a typical place in the zone:

  • April 30Risky: a later frost happens in 9 years out of 10
  • May 13Typical: frost after this date in half of years
  • May 27Safe: a later frost only 1 year in 10

Your dates for broccoli

Set your ZIP code at the top of the page and we will work out when to plant broccoli where you live, from the frost records of the nearest NOAA weather station. Your ZIP code is remembered on this device only.

Enter your ZIP code

Broccoli in zone 4a cities

CityTypical last frostStart indoorsPlant out
Fargo, NDMay 10Feb 22 to Mar 15Apr 12 to 26
Bismarck, NDMay 14Feb 26 to Mar 19Apr 16 to 30
Grand Forks, NDMay 10Feb 22 to Mar 15Apr 12 to 26

How to grow broccoliAll zonesBroccoli in zone 3bBroccoli in zone 4bAbout zone 4a

Sources