In Indiana, the best time to plant tomatoes is generally after the last frost date when the soil temperature is warm enough, ideally around 55 to 60 degrees Fahrenheit. This timing usually falls around mid to late April in southern Indiana and early to mid-May in northern Indiana. Many gardeners wait until after Mother's Day in early May to be safe from any late frost risks. For starting tomato seeds indoors, it is recommended to begin about 6-8 weeks before the last frost date, which means starting seeds indoors in late February to early March. Transplant tomato seedlings outdoors once the soil and air temperatures are suitable, typically in May. To summarize:

• Last frost date varies by location in Indiana but is mostly between late April and early May.
• Plant tomato seedlings outdoors after the last frost, around mid-May.
• Start tomato seeds indoors 6-8 weeks earlier, in late February to early March.

Plant tomatoes in full sun and consider using cages or stakes for support. Also, protect plants from cold soil and frost to avoid stunted growth or damage.