When to plant sunflowers in zone 5a
In zone 5a, where the last spring frost typically comes around May 3, sow outdoors May 3 to 24.
The zone 5a schedule for sunflowers
- Sow outdoors
- May 3 to 24
- Safest planting date (10% frost risk)
- May 17
- First harvest, roughly
- June 22 to August 22
From the median frost dates of the NOAA stations assigned to the 2,200 ZIP codes in zone 5a, and the timing recommended by Cooperative Extension guides for sunflowers.
Frost risk in zone 5a
Zones are based on winter cold, not on frost dates, so the last spring frost varies a lot within a zone. Across zone 5a, the typical last frost ranges from about April 27 in the earliest tenth of ZIP codes to May 21 in the latest tenth, and the first fall frost from September 25 to October 13. For a typical place in the zone:
- April 20Risky: a later frost happens in 9 years out of 10
- May 3Typical: frost after this date in half of years
- May 17Safe: a later frost only 1 year in 10
Sunflowers are killed by frost, so if you want to be safe, plant out after the safe date rather than the typical one, or be ready to cover plants on a cold night.
Your dates for sunflowers
Set your ZIP code at the top of the page and we will work out when to plant sunflowers where you live, from the frost records of the nearest NOAA weather station. Your ZIP code is remembered on this device only.
Sunflowers in zone 5a cities
| City | Typical last frost | Plant | Fall |
|---|---|---|---|
| Minneapolis, MN | Apr 23 | Apr 25 to May 16 | — |
| St. Paul, MN | Apr 23 | Apr 25 to May 16 | — |
| Anchorage, AK | May 5 | May 23 to Jun 13 | — |
| Sioux Falls, SD | May 1 | May 1 to 22 | — |
| Cedar Rapids, IA | Apr 28 | Apr 28 to May 19 | — |
| Billings, MT | May 10 | May 10 to 31 | — |
| Bloomington, MN | Apr 23 | Apr 23 to May 14 | — |
| Sioux City, IA | Apr 29 | Apr 29 to May 20 | — |
| Brooklyn Park, MN | Apr 30 | Apr 30 to May 21 | — |
| Woodbury, MN | Apr 24 | Apr 24 to May 15 | — |
| Plymouth, MN | Apr 29 | Apr 29 to May 20 | — |
| Blaine, MN | Apr 30 | Apr 30 to May 21 | — |
How to grow sunflowersAll zonesSunflowers in zone 4bSunflowers in zone 5bAbout zone 5a
Sources
- Dakota Gardener: Grow a bouquet in 60 days · NDSU Extension (North Dakota State University)
- Growing Sunflowers in the Home Garden (Circular 1121) · University of Georgia Cooperative Extension
- Let's Grow Sunflowers · Clemson Cooperative Extension Home & Garden Information Center
- How to sow sunflowers in successful succession · Mississippi State University Extension
- How to Grow Sunflowers (Garden Notes GN 166) · UC ANR Cooperative Extension Sacramento County Master Gardeners
- Sunflowers · UF/IFAS Extension Gardening Solutions
- Flowers to Plant in Florida: Text (month-by-month calendar for North, Central and South Florida) · UF/IFAS Extension Gardening Solutions
- Flower Planting Guide for the Low Desert (AZ1100) · University of Arizona Cooperative Extension, Maricopa County
- Sowing Annual Seeds · Penn State Extension
- May 21, 2005 Timely Tips (Bexar County gardening calendar) · Texas A&M AgriLife Extension, Bexar County