Tomato Blossom End Rot

This is a physiological disorder common to tomatoes and peppers in particular. It is the result of a calcium imbalance in the plant, often brought on be erratic watering or temperature fluctuations, but occasionally by an actual lack of calcium in the soil. Hard pruning can make it worse as can overuse of nitrogen-rich fertilizer. You can add calcium as a spray (available at your local garden center), for future developing tomatoes. Harvest and cut off the affected fruit as a green tomato as it will likely rot from here on. Or you can wait to see if the affected fruit ripens. If it does, the fruit is edible except for the hard brownish part of the blossom end rot. Just cut around it. Once the blossom end rot occurs on your fruit it cannot be reversed. For future developing tomatoes, be sure to keep your tomatoes evenly watered, but not soggy and feed with a slow release or organic fertilizer formulated for tomatoes.