I see you got a couple of answers to your post of this question over on the Tomato Forum here. Some also suggested you check with the folks on the Florida Gardening forum as they can advise you specifically about timing in Florida.

From what I have read in the past from Florida Gardeners, yes it is too late for planting now to beat the heat and the blossom drop that results. You have 2 tomato growing seasons down there - Fall and Winter to very Early Spring.

As to container sizes, Better Boy is a very large indeterminate variety that can easily grow to 6-8 feet tall or taller and will need a very large container (7-10 gallons minimum is common) and good support. I linked a picture of an average plant below.

Dave

Here is a link that might be useful: Better boy tomato plant

Since you're new to vegetable gardening, you might be interested in the online information the University of Florida has to offer. I used to use their website quite a bit before Texas A&M did their make-over, and found it very useful.

Here is a link that might be useful: UFL vegetable gardening link

There was a test of size of "Better Boy" tomatoes plants & weight of fruit in containers.
Soil volume 4cu.ft 2cu.ft. 1/2cu.ft.
Height.......66"......56".........46"
Fruit.........58.......48...........12
That test is a old one & was not organic, but everything was the same, only the volume of soil varied.
All About Tomatoes. South Edition

So my tomatoes are going to die?
:(

When the temps get up over 95 they will be hard to keep alive without a lot of water but they will stop producing at that time. Right now mine are over 4foot tall and blooming with the hope that they will produce enough fruit before we get our hot weather here. I am also trying Homestead as they say they may be able to stand more heat, I will see how that goes as they also are over 4 foot and blooming.

Let us know how it goes as nothing beats a try.

"So my tomatoes are going to die?"

Not from the heat if you keep them watered. The Better Boy is a tough variety and will definitely survive the heat if taken care of. They just get so big they need lots of room to grow.

If you can find a spot that gets good sun in the morning and mid-day, then shade in the afternoon when its really hot, the plants will do better.

When daytime temps rise consistently above 95 or night temps above 75, the blooms will fall off and you won't get any fruit set. But the plant will continue to grow and bloom and when cooler weather comes, the plant will start producing tomatoes again.

You should plan on giving each plant at least one gallon of water every 4-7 days as required to keep soil moist.

So would a 10 gallon pot be a good size if I keep them in pots?

Everglades cherry is one of the very few that will produce fruit right through florida summer. Highly nematode tolerant also. Too late for starting from seed now though, but keep it in mind for next year. People on the florida forum have seed.

So would a 10 gallon pot be a good size if I keep them in pots?

I already answered this above. A 10 gallon pot for each plant, filled with a high quality soil-less potting mix, a supporting cage at least 4' tall, watered and fed regularly, and kept in partial sun/shade should survive until it is cool enough to produce fruit IF it doesn't get a disease or develop a problem with pests in the meantime.

The point is you are starting out with 3 strikes against you already: 1) wrong planting time for Florida, 2) trying to grow an indeterminate variety in a container, 3) lack of knowledge/experience. Odds of success are slim but it can be a good learning experience.

Dave

Yea I don't think their going to make it, well it was 5 plants for a dollar so I didn't lose a lot of money and now I know when to plant them. Someone at my garden store told me to plant okra seeds now,so, I'm going to try that.