When to plant sweet corn
Vegetable, tender
Direct-sow around the last-frost date and do not bother transplanting. CSU's germination minimum is 50°F and its harvest range is 60–90 days; Wisconsin says plant at 55°F and Clemson lists 80–95 days, so the harvest window here spans those figures.
The general rule
- Sow outdoors
- at the last spring frost
- Plant when soil reaches
- 55°F
- Days to maturity
- 60–95 days
What that means in different climates
The same rule applied to the safer frost dates of cities from cold to frost-free.
| City | Last frost · safer | Sow outdoors |
|---|---|---|
| San Jose, CA | Jan 23 | Jan 23 – Jan 23 |
| Tucson, AZ | Mar 2 | Mar 2 – Mar 2 |
| Portland, OR | Mar 21 | Mar 21 – Mar 21 |
| Baltimore, MD | Apr 4 | Apr 4 – Apr 4 |
| New York, NY | Apr 12 | Apr 12 – Apr 12 |
| Nashville, TN | Apr 16 | Apr 16 – Apr 16 |
| Louisville, KY | Apr 23 | Apr 23 – Apr 23 |
| Omaha, NE | May 6 | May 6 – May 6 |
| Colorado Springs, CO | May 15 | May 15 – May 15 |
| Miami, FL | Frost rare | Frost is rare: late winter to spring; late summer to fall (soil 55°F+). |
Sources
- Colorado State University Extension, Vegetable Planting Guide (GardenNotes #720)
- University of Wisconsin-Madison Extension, When Is the Right Time to Plant Vegetable Seeds? Check Soil Temperature
- Clemson Cooperative Extension HGIC 1256, Planning a Garden
- Clemson Cooperative Extension HGIC 1259, Starting Seeds Indoors