I had heard lack of Calcium could be a contributor to blossom end rot?
I'm not the biggest fan of a drip irrigation, keeping the soil from drying out on occasion (if that's what you mean, keeping the soil from drying out?)
I prefer to allow some drying out of the soil to occur, in hopes it encourages the plants to send out a good root system.
When I put my tomatoes in, I lay them down in trenches, so only about 3 branches are exposed and then cover with soil. The Plant straightens itself within the first day and the buried stem produces even more roots along itself. I don't know if this method of planting has made a difference but I've never had an issue (YET, knock on wood!!!) with Blossom end rot.

Blossom end rot is always a hard one. It is a calcium issue also the plant is growing so rapidly that it doesn't utilize the calcium it does have. It moves more calcium to the growing points of the plant instead of the tips of the fruit. Also, stress on the plant going from cool and wet to hot and dry can cause this issue. There are many factors that are involved in the physiological disorder.

We have been using Calcium Nitrate 15.5-0-0 through the drip tape every week and it seems to help. But every year you are going to have this to some extent. In my opinion, some varieties do this much worse than others. It always seems my Big Beefs always do this worse than my Fl 91's.

We don't add lime to our soil as our soil is already too high in pH (7.2 to 7.4) so we add sulfur to help bring it down. We do this twice a year and have seen a .1 to .3 reduction in different areas over time.

Jay

I use calcium nitrate and I still get it, so I just buy a 1/2 gallon of milk and feed it to my 5 plants, and blossom end rot is no more.

yes have heard it is calcium issue, which may lead from inconsistent watering, dissolve some gypsum in bucket and apply around the root zone.

we use oodles of green type mulches 6" to 8" thick, also try hilling up around the plants to encourage more root development. we do that as well.

len

Here is a link that might be useful: lens garden page

For facts about BER, rather than popular wisdom, see the Tomato Forum FAQ at http://faq.gardenweb.com/faq/tomato/

Here is a link that might be useful: BER is 2nd item in FAQ

BER is usually (not always) caused by the gardener, not the soil with Irregular watering being the culprit. The soil should not dry out or be too soggy. The problem is more common in sandy soils. It's not always that calcium is lacking in the soil, but that it isn't reaching the cells in the fruit. It is more common in larger tomatoes. You don't see cherry tomatoes with BER.

Here is a link that might be useful: Blossom end rot