After 2 years of fairly poor results, I am not trying to grow any large tomatoes this fall with one exception. I am growing mostly cherries and medium fruit varieties. Here's what I will probably grow:
I am starting tomato seeds next week (June 8-15th) indoors and will plant plants in late July.
Because of the extreme heat and bright sun, plants will require careful handling. I will harden off for 7-10 days, starting with full shade and then gradually introducing them to morning and afternoon sunlight in 10-15 minute increments until they can finally handle the worst sun -- 11am-2pm. One solution is to place a lawn chair or 2x4's (supported by cinder blocks) over the plants so they get morning and afternoon sun but are shaded during midday. You can start hardening off in early July if you have cloudy days (much safer) or just more time to devote to the plants.
Keep in mind this is for Houston which is a bit different than Dallas. You might have cool temps 2-3 weeks before we do. I'd start seeds soon.
I grew lots of large and medium fruited varieties last fall and let me tell you, it is very frustrating to have all this green fruit hanging on the plants, but then it gets cold and ruins the flavor of the fruit. Even though I can get a lot of fruitset in September, the plants slow down as they get less and less sunlight as the angle of the sun changes. They don't ripen until late October or November.
I know that in my horticulture class , the vegetable garden for the Fall semester class already had tomatoes growing from the spring classes. We trimmed them up
and added compost and let them grow somemore. There were Early Girls and Sweet 100's and yellow pear. THey produced SO much. Naturally all our vegetables
looked great because we didn't have the same bug problem as the Spring class did. Have fun, I can't wait to just let my tomatoe plants now,grow through the Fall.Oh, I'm in Gainesville,Texas.
Where I'm at you can imagine we get cooler weather a little sooner than Houston, but when it forecasted too cold of weather some of us picked the best tomatoes and took them home and layed them in a dark corner on newspapers on shelves. They continued to ripen. THey didn't have the same flavor for sure but oh well, it was fun doing it.