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When to plant tomatoes in zone 6a

In zone 6a, where the last spring frost typically comes around April 29, start tomatoes indoors March 24 to April 7 and plant out May 19 to June 2.

The zone 6a schedule for tomatoes

Start seeds indoors
March 24 to April 7
Plant out
May 19 to June 2
Soil warm enough (60°F), about
May 19
First harvest, roughly
July 10 to August 31

From the median frost dates of the NOAA stations assigned to the 4,514 ZIP codes in zone 6a, and the timing recommended by Cooperative Extension guides for tomatoes.

Frost risk in zone 6a

Zones are based on winter cold, not on frost dates, so the last spring frost varies a lot within a zone. Across zone 6a, the typical last frost ranges from about April 16 in the earliest tenth of ZIP codes to May 11 in the latest tenth, and the first fall frost from October 4 to October 24. For a typical place in the zone:

  • April 16Risky: a later frost happens in 9 years out of 10
  • April 29Typical: frost after this date in half of years
  • May 14Safe: a later frost only 1 year in 10

Tomatoes 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 tomatoes

Set your ZIP code at the top of the page and we will work out when to plant tomatoes where you live, from the frost records of the nearest NOAA weather station. Your ZIP code is remembered on this device only.

Enter your ZIP code

Tomatoes in zone 6a cities

CityTypical last frostStart indoorsPlant out
Chicago, ILApr 11Mar 17 to 31May 12 to 26
Indianapolis city, INApr 15Mar 10 to 24May 5 to 19
Denver, COMay 4Mar 27 to Apr 10May 22 to Jun 5
Colorado Springs, COMay 3Mar 29 to Apr 12May 24 to Jun 7
Omaha, NEApr 18Mar 12 to 26May 7 to 21
Aurora, COMay 4Mar 27 to Apr 10May 22 to Jun 5
Lincoln, NEApr 24Mar 14 to 28May 9 to 23
Fort Wayne, INApr 24Mar 17 to 31May 12 to 26
Grand Rapids, MIApr 29Mar 24 to Apr 7May 19 to Jun 2
Lakewood, COMay 5Mar 30 to Apr 13May 25 to Jun 8
Springfield, MAMay 3Mar 25 to Apr 8May 20 to Jun 3
Joliet, ILApr 19Mar 21 to Apr 4May 16 to 30

How to grow tomatoesAll zonesTomatoes in zone 5bTomatoes in zone 6bAbout zone 6a

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