Definitely sounds like blossom end rot. But before you go out spreading lime or lose time waiting for a soil test, just start watering on a regular schedule and be watchful of stressing your plants. While calcium is the cause, most often uneven watering is the trigger, especially when the plants are growing fast. Going too long without a watering or going though a series of hot, windy days when the plants lose a lot of water stresses the plant's ability to do all those things like take up calcium at an even rate. The deficiency strikes the fruit and the next thing you know you've got blossom rot. Most of the time, attention to watering will get you through the problem. Out of lurk, David "Zeb" Cook