Well Im no expert but I live in Florida and I have had problems with tomato blossoms. Its not that they were not coming its just that they kept falling off due to the heat. So here is what I did to my five gallon containers. I raked up a bunch of dried leaves and I crumbled them all and spread them around the base of the plant as mulch. I did this so that the container would retain moisture and the mulch would reduce the stress of the heat to the root system. And apparently it worked. So far none of my Brandywine blossoms have fallen off. That�s the only advice this newbie can give I hope it helps.

Try a shade cover with about 50% shade. They sell them online Orin garden stores. When it gets really hot they just won't set, not much you can do about it.

As Ecopal said, tomatoes don't actually stop blooming because of heat, they may stop setting fruit, because temperatures over 90-95 degrees during the day or 70-75 degress at night can cause pollen to become sterile. High humidity can cause pollen to form clumps so that it can't fertilize the ovaries.

I'm not saying you didn't see times when tomatoes stop blooming, as some determinate tomatoes may bear a majority their crop over a short time period, then die back or go dormant. In areas with long growing seasons, you might see a second round of blossoms from a such a determinate.

I hope that helps.

Betsy

Here is a link that might be useful: "Blossom Drop" FAQ