I tried two plants in 4 gallon pots. One plant bolted, the other stunted. Neither is looking good at the moment.
I treated both of them the pretty much the same,

Meanwhile, the tomato I put in the traditional garden is looking GREAT, with pretty much the same amount of watering.

So a few things - some varieties are just prone to BER (roma types especially - a genetic trait). Some always BER the first few fruit then the rest are fine.

But in containers, it is hard, without drip irrigation, to keep even watering on a plant. So the plants set fruit, then it gets hot, and the plants don't get the water they need and start to wilt a bit - the plant goes into preservation mode (damn the fruit...I am saving myself!).

I think the best you can do - water often when it is really hot, try to not let the plants visibly wilt, and add a tbsp or two of pelletized lime in a circle around the base of the plant and scratch it in.....do this every 3 weeks or so, since in containers, nutrients can wash out more easily with so much needed watering.

Of my 200 or so tomato plants in pots, the occurrence of BER is here and there - definitely some element of variety susceptibility, but even more due to the nasty 100 plus degree days we seem to be endlessly having here.

so maybe things will get better with subsequent fruits. I water the plants the same time every day (early morning) and when it gets hot-hot (105+), will come back and water them in the late afternoon. I'll definitely try the lime pellet idea. I think this is going to be my last year trying to grow Roma's and Celebrities as they seem to be the most susceptible to BER. Any suggestions as to varieties that are less susceptible?

Btw, you've been a great source of information for this fellow container gardener.

Thanks again,

LTH

http://nctomatoman.weebly.com/1/category/container%20gardening/1.html

http://upload.democraticunderground.com/discuss/duboard.php?az=view_all&address=246x12904

I grow all my tomatoes in containers and use the milk bath regularly and have never had any problems with BER. The milk bath really seems to help with production so you might also see your plants replacing those rotted fruits faster.

Hope everything settles out for you soon.

I had a really good harvest this year, probably close to 200 tomatoes and about 300 cherry tomatoes.

I only recently started getting bottom rot.

A couple of things I have noticed.

The tomato season (at least here in Austin, Texas) is coming to a close. The reason is because of soil temp.

Like all veggies and fruits, there is an optimum temp for each. And when the temp either gets too high or too low, the plant will begin to die.

I noticed that I got my bottom rot when the temps were consistently above 95 degrees. This would mean, even with shading cloth, that the soil temps are consistently warmer. The evening cooling (because of the consistent high temp) doesn't seem to have any effect on helping the fruit grow.

I could be a matter of watering too much but I don't think so, I have watered the same amount all season.

It might be because of the higher soil temp the interior of the fruit is being stressed, thus causing the rot.

I noticed that some of the tomatoes were ripe and some were in the mid ripe stage and both had the rot.

Which leads me to believe that it's not watering and more of a temp issue.

Just my two cents.

My full sized tomato plants (especially Rosella varieties) have had issues with BER this season. They are the first set of fruits and since I noticed the problem I've fertilized the containers again and given them the "milk bath" that a lot of people here have recommended. Cherry tomatoes (cherry punch hybrid) have not had any problems and are producing like crazy. In ground tomatoes don't seem to be having a problem either.

It was recommended by the nursery. Seems to be working well so far. Keeping my fingers crossed.

We'll see!

Once it starts, try adding potash and kelp (top dressing). It won't stop it, but it will lessen the rot. And it's fine to cut off the rotted part and eat the rest of the tomato.

here in new mexico agricultural gypsum worked well..in fact it seemed to be the only thing that worked..

So, after reading over all the suggestions (you see my dilemma from the OP, i.e., many suggested solutions) I decided to try the easiest one first -- do nothing and see if the BER just affects the first few tomatoes. That did it! Apparently only the first ones were affected and all subsequent maters were fine.

That's not to say that all the suggestions of the above experienced gardeners were not legitimate but there are so many variants possible, climate, heat, watering schedule, soil additives, container or ground planting, etc. I've written down ALL the suggestions above and if my first solution doesn't work I now have lots of options.

Thanks everyone for your help!

LTH