by Matt Gibson (revised and updated) The 30-second version: Blossom-end rot isn’t a disease and it isn’t contagious. It’s a calcium problem inside the fruit — and that’s almost always caused by uneven watering, not by a lack of calcium in your soil. Fix your watering, mulch to hold moisture steady, and stop reaching for the eggshells … Continue reading Tomato Diseases: How To Fight Blossom-End Rot