When to Plant Tomatoes
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GardenSays
Start tomato seeds indoors Mar 17 โ Mar 31; transplant once frost danger is past and soil has warmed to ~60ยฐF โ typically May 12 โ May 19 here.
- Start seeds indoors
- Mar 17 โ Mar 31
- Transplant outside
- May 12 โ May 19
- Last frost (typ.)
- May 5
In Minneapolis, MN, the typical last frost lands around May 5. Working back 6-8 weeks from transplant time gives you a seed-starting window of Mar 17 โ Mar 31 indoors. Tomatoes are frost-tender, so wait for two conditions โ frost danger past AND soil around 60ยฐF โ which here typically means May 12-May 19.
- This year's transplant window (May 12 โ May 19) has passed โ dates shown are for planning next season.
Do this this week
- 1.Passed for this season โ plan next spring: start seeds indoors ~Mar 17 โ Mar 31, transplant ~May 12 โ May 19
Calculated result ยท 3 verified sources ยท Checked 2026-07-15 ยท How we decide
Why
That leaves roughly 139 days of growing season before the typical first fall frost (Oct 5) โ enough for most varieties. In a short-season area, favor early-maturing varieties (check the days-to-maturity on the tag).
- Frost kills tender seedlings outright, and cold soil stunts them even without frost โ both dates matter.
- The 50% frost date is a planning midpoint: a late frost is still possible, so keep covers handy for the first two weeks.
When this doesn't apply
- Season extenders (row covers, walls of water, cold frames) let you plant 2-3 weeks earlier than these windows.
- Frost dates are area averages โ low spots and valley floors run colder than the local average.
How this was calculated
- 1. Last spring frostMay 5Source guidance
Minneapolis, MN: typical (50% probability) last 32ยฐF frost
- 2. Seed starting windowMar 17 โ Mar 31Calculated result
Tomato: start indoors 6-8 weeks before your typical transplant date
- 3. Transplant windowMay 12 โ May 19Calculated result
Tomato is frost-tender: go out 7-14 days after the last frost, once soil reaches 60ยฐF
- 4. First fall frostOct 5Source guidance
Minneapolis, MN: typical first 32ยฐF frost in fall โ the season's endpoint
Data sources
- University of Minnesota Extension โ Growing tomatoes in home gardens โ Start tomato seeds indoors about 6 weeks before the last frost; transplant after all danger of frost, once soil has warmed. (checked 2026-07-15)
- NOAA NCEI โ 1991-2020 U.S. Climate Normals (freeze date probabilities) (checked 2026-07-15)
- National Gardening Association โ frost date lookup (checked 2026-07-15)
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People also ask
When should I start tomato seeds indoors?
Start tomato seeds indoors Mar 17 โ Mar 31; transplant once frost danger is past and soil has warmed to ~60ยฐF โ typically May 12 โ May 19 here. Calculate yours โ
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When to plant tomatoes in zone 5?
Start tomato seeds indoors Mar 22 โ Apr 5; transplant once frost danger is past and soil has warmed to ~60ยฐF โ typically May 17 โ May 24 here. Calculate yours โ
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