My tomatoes are turning brown on the bottom.
Hardiness Zone: 6b
By Cecil from Paducah, KY
This is probably blossom end rot. It occurs at the bottom of the tomato and sort of looks like a bruise that may or may not be indented somewhat. Crushed egg shells in the dirt will replace a calcium shortage which is frequently the cause. Also, too much water and/or fertilizer (indicated particularly if you have plants that are very tall but not bearing much fruit) can cause blossom end rot. Pick the affected fruit as soon as you notice the problem so the plant's energy is spent on healthy fruit instead. Usually only affects some of the fruit on a plant, and most often only the first fruits.