If it ain't one thing with tomatoes, it's another.
I returned home from vacation to find - not the early blight that we all feared would return with renewed vengence this season -- but blossom-end rot.
The bottoms of my tomatoes - just where the blossom disappears -- are brown and mushy.
Unlike blight, this is not caused by spores and it isn't caused by pests. It is, instead, a problem with the plant's growing conditions.
Blossom-end rot, which also effects watermelons and peppers, is generally caused by a calcium deficiency in the soil.
I have had it appear before, and I tried to head it off this year by adding egg shells to the hole in which I plant my tomatoes. I could have also applied some gysum or lime several weeks before planting. And I have even heard other gardeners using Tums with calcium when planting!
I also sprayed a non-toxic potion of calcium chloride on the foliage, but two things conspired to defeat me: I wasn't consistent about spraying -- it should be done every week -- and the drought and deluge cycle of weather this summer hindered the uptake of calcium from the soil.
You can recognize blossom-end rot by a small wet area at or near the bottom of the fruit. This becomes darker and larger as the fruit develops, and it takes on a leathery look. On peppers, the spot will look tan. In tomatoes and watermelons, it becomes black.
I can't save the tomatoes that already have blossom-end rot, but I am committing to more consistent spraying to spare the next batch of fruit, which is just now in its blossom stage.