The best time to plant tomatoes in Tennessee is after the last frost date, which varies by location but generally falls between early to late April. For example, the last frost dates range from around April 8 in Memphis and Knoxville to about April 29 in Franklin and Kingsport. It is recommended to plant tomatoes outdoors when nighttime temperatures consistently stay above 50°F, and soil temperatures are above 60°F, typically after mid-April to early May. Many Tennessee gardeners follow the rule of transplanting tomato seedlings into the garden around mid-April to early May, often around the time of Mother's Day for safety from late frost. Tomatoes can be started indoors as early as mid to late February and then transplanted outside once the risk of frost has passed and plants have been hardened off. Summary by zones and cities for last frost dates and planting:

• Memphis and Knoxville: Last frost early April (around April 8-9)
• Nashville and Chattanooga: Mid-April (April 16-18)
• Franklin, Kingsport: Late April (April 29)
• General safe planting time outdoors: Mid-April to early May (after last frost and soil warming)

This schedule allows tomatoes to grow during the warm season, with harvest times typically from June to October in Tennessee.