When to plant sunflowers in zone 6b
In zone 6b, where the last spring frost typically comes around April 23, sow outdoors April 23 to May 14.
The zone 6b schedule for sunflowers
- Sow outdoors
- April 23 to May 14
- Safest planting date (10% frost risk)
- May 9
- First harvest, roughly
- June 12 to August 12
From the median frost dates of the NOAA stations assigned to the 4,514 ZIP codes in zone 6b, and the timing recommended by Cooperative Extension guides for sunflowers.
Frost risk in zone 6b
Zones are based on winter cold, not on frost dates, so the last spring frost varies a lot within a zone. Across zone 6b, the typical last frost ranges from about April 10 in the earliest tenth of ZIP codes to May 6 in the latest tenth, and the first fall frost from October 9 to October 29. For a typical place in the zone:
- April 8Risky: a later frost happens in 9 years out of 10
- April 23Typical: frost after this date in half of years
- May 9Safe: 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 6b cities
| City | Typical last frost | Plant | Fall |
|---|---|---|---|
| Columbus, OH | Apr 18 | Apr 18 to May 9 | — |
| Boston, MA | Apr 4 | Apr 19 to May 10 | — |
| Detroit, MI | Apr 21 | Apr 21 to May 12 | — |
| Kansas City, MO | Apr 4 | Apr 4 to 25 | — |
| Cleveland, OH | Apr 8 | Apr 18 to May 9 | — |
| Cincinnati, OH | Apr 16 | Apr 16 to May 7 | — |
| Pittsburgh, PA | Apr 24 | Apr 24 to May 15 | — |
| Buffalo, NY | Apr 24 | Apr 26 to May 17 | — |
| Toledo, OH | Apr 20 | Apr 20 to May 11 | — |
| Boise City, ID | Apr 24 | Apr 24 to May 15 | — |
| Spokane, WA | Apr 26 | Apr 26 to May 17 | — |
| Rochester, NY | Apr 24 | Apr 24 to May 15 | — |
How to grow sunflowersAll zonesSunflowers in zone 6aSunflowers in zone 7aAbout zone 6b
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