When to plant broccoli in zone 4b
In zone 4b, where the last spring frost typically comes around May 8, start broccoli indoors February 20 to March 13 and plant out April 10 to 24. For a fall crop, plant July 16 to August 13.
The zone 4b schedule for broccoli
- Start seeds indoors
- February 20 to March 13
- Plant out
- April 10 to 24
- Sow outdoors
- April 17 to 24
- First harvest, roughly
- May 30 to July 8
- Plant for a fall crop
- July 16 to August 13
From the median frost dates of the NOAA stations assigned to the 1,164 ZIP codes in zone 4b, 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 4b
Zones are based on winter cold, not on frost dates, so the last spring frost varies a lot within a zone. Across zone 4b, the typical last frost ranges from about May 1 in the earliest tenth of ZIP codes to May 25 in the latest tenth, and the first fall frost from September 22 to October 8. For a typical place in the zone:
- April 26Risky: a later frost happens in 9 years out of 10
- May 8Typical: frost after this date in half of years
- May 22Safe: 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.
Broccoli in zone 4b cities
| City | Typical last frost | Start indoors | Plant out |
|---|---|---|---|
| Rochester, MN | Apr 30 | Feb 12 to Mar 5 | Apr 2 to 16 |
| Duluth, MN | May 6 | Feb 18 to Mar 11 | Apr 8 to 22 |
| Lakeville, MN | May 2 | Feb 14 to Mar 7 | Apr 4 to 18 |
| St. Cloud, MN | May 7 | Feb 19 to Mar 12 | Apr 9 to 23 |
| Eau Claire, WI | May 8 | Feb 20 to Mar 13 | Apr 10 to 24 |
| Great Falls, MT | May 19 | Mar 3 to 24 | Apr 21 to May 5 |
How to grow broccoliAll zonesBroccoli in zone 4aBroccoli in zone 5aAbout zone 4b
Sources
- Broccoli in the Garden (How to Grow Broccoli in Your Garden) · Utah State University Extension
- Broccoli (HGIC 1301) · Clemson Cooperative Extension Home & Garden Information Center
- Growing Broccoli in a Home Garden · University of Maryland Extension
- Growing Broccoli in the Home Garden · Iowa State University Extension and Outreach
- Florida Vegetable Gardening Guide (SP 103/VH021) · University of Florida IFAS Extension
- Vegetable Planting Calendar for Maricopa County (AZ1005) · University of Arizona Cooperative Extension
- RGV Homeowner Vegetable Guide (rev. 2022) · Texas A&M AgriLife Extension Service
- Soil Temperature Conditions for Vegetable Seed Germination (Garden Notes GN 154) · University of California Cooperative Extension, Sacramento County
- Easy Container Vegetables and How to Grow Them · N.C. Cooperative Extension, Onslow County Center
- Vegetable Gardening in Containers (E-545) · Texas A&M AgriLife Extension Service