Planting calendar
When to plant tomatoes in Iowa
Iowa spans USDA hardiness zones 4b-5b. Average last spring frost: 05-05. This calendar gives you the indoor start, transplant, and direct-sow dates for Solanum lycopersicum.
Iowa planting dates for tomatoes
| Phase | Date in Iowa | Notes |
|---|---|---|
| Start seeds indoors | March 10 | 8 weeks before last frost |
| Transplant outdoors | May 19 | 2 weeks after last frost |
Why these dates
Tomatoes are warm-season crops that need 6-8 hours of direct sun and soil temperatures above 60F to thrive. Indeterminate varieties need staking or caging. Determinate varieties stay bushier and ripen all at once.
The dates above are anchored to Iowa's average last spring frost date of 05-05, with offsets standard across university Extension publications. For zone-specific local timing, use the frost date lookup tool with your ZIP code.
More on growing tomatoes
The full growing guide for tomatoes - varieties, soil, fertilization, pests, harvest, storage - is here: Tomatoes growing guide.
More Iowa planting information
- Full Iowa planting calendar (all crops + ornamentals)
- Find your exact USDA zone by ZIP
- Look up your average frost dates
- Seed starting timeline calculator