Sweet corn
Vegetables · Sow outdoors or set out
Sweet corn planting dates
At usual odds in 2026: Apr 27 – May 18.
The guide's rule From last frost to 3 weeks after last frost.
Frost odds · chance of a freezing night after your spring date
The 2026 season
Start indoors Plant out / sow Frost risk
At all three odds
| Frost odds | Start indoors | Plant / sow |
|---|---|---|
| Bold (1 in 2) | Mar 23 – Apr 13 | Apr 20 – May 11 |
| Usual (3 in 10) | Mar 30 – Apr 20 | Apr 27 – May 18 |
| Careful (1 in 10) | Apr 7 – Apr 28 | May 5 – May 26 |
- Days to first harvest
- 70-90 from seed
- How it goes in
- Sow outdoors or set out 4 weeks indoors to transplant size
- Frost
- Frost-tender A freezing night kills it.
- Soil to germinate
- 55-85°F
Frost-tender: a single 32°F night can kill it. Early in the window, keep a cover handy or choose careful odds.
Plan it in your Garden Book
The book checks your date against the window and tells you when the first harvest could come.
Plus Free Garden Books hold 8 plantings a season; Seed Clock Plus holds 120: $1.95/month or $19.50/year. Free during preview What Plus adds
Source: Montana State University Extension, MontGuide MT199308AG, "Can I Grow That Here? Vegetable Seed and Transplant Schedules for Garden or Container" (reviewed August 2013), read with NOAA 1991-2020 freeze odds for Cleveland Hopkins. Wording ours; how we read the guide.