A: This question is one whose answer can vary, wildly. If you ask ten gardeners when to plant your tomatoes, be prepared for nine different answers!
Our average last spring freeze is around March the 17th in our area of Texas, which means that sometime in late March or early April is usually safe. Many gardeners choose Easter as their target planting date for this reason. But Easter is a very odd sort of holiday! It wanders around the calendar. Don’t use Easter to judge your planting date. If you won’t be able to cover your garden from late cold snaps at all, plant late this month or early next, after consulting the ten day forecast.
In my own garden, I tend to plant as early as tomato starts are available in early March. Early March is NOT safe, to be clear. Roughly every other year, I’m going out at least once with frost cloth, five-gallon nursery buckets, and piles of compost to insulate my tomato starts from a late cold snap. But there’s a good reason to go to this trouble! Tomatoes don’t set fruit well at high temperatures, and the summer heat often drives tomatoes out of production, particularly for larger fruited varieties. Tomatoes planted earlier – IF you can get them through any late cold snaps – will be better set up to produce when temperatures hit the optimal range for production in the Spring.