try some bonemeal [or other calcium] and epsom salt and useing a weak fish fert solution once a week - also make sure the medium they're in isn't drying out as fast as you water it, which I'd expect that mix might

Bill

The best tomato "fertilizer" is compost and other organic matter, lots. Tomatoes do very well in a soil well endowed with organic matter that is evenly moist but well drained and a place that gets at least 6 hours of sun each day.
A good, reliable soil test will tell you whether your soil has optimum nutrient levels. Contact your local office of your states USDA Cooperative Extension Service about that.

Everything has been slow to start for me this year because of cool weather. I hope it's not as bad as last year- I had incredible production, but ripening was slow and many peppers never fully ripened.

It could just need a little time. It sounds like you have a ton of organic matter in there. Don't overfertilize or you'll end up with barren tomato trees.

Last year for the first time our tomatoes had no blossom end rot. That, I believe, is because we followed the advice of a tomato-growing aficionado who said, fertilize the soil with compost the year before you plant the tomatoes, and not at all in the year they're growing, except a shot of something at transplanting time. Rich soil spoils tomatoes. Give them tough love. Also keep the soil evenly moist, and covered with mulch. No BER, and very little splitting.

Your soil sounds more than rich enough. Are the leaves yellowing at all? And it's been a very cold spring here too. Could be the weather is slowing them down as pablo says.

Very interesting - fertilize the year before... A dose of calcium of some sort seems to do the trick as squeeze suggests.

The gurus on the tomato forum will tell you that blossom-end rot is almost never the result of a shortage of calcium in the soil.

Perhaps this article from the National Gardening Association will help some people.

Here is a link that might be useful: When good tomatoes go bad