If you're in North Texas, you now have my blessing to go ahead and plant tomato transplants. Yay! A bit early you say? It's probably going to freeze again right? Yes, it probably will. But with tomatoes, the earlier you can get them in the ground here the better. If you're willing to keep frost cloth or water wall protectors on hand, planting now will ensure you the best opportunity to get fruit set before temperatures get out of range. Peak planting time will be right about mid-March, then it needs to taper off through the end of March. Then I'll cut you off April 1st, lol.
If we drop below about 35F, cover your tomatoes with frost cloth. That does the trick. If you want to read a bit more about tomatoes I have a number of posts about them on the blog- just "tomatoes" in the search box to the right and you'll get a list of posts. Enjoy!