At a glanceThe main cause is a lack of calcium in the developing fruit.Tomatoes need calcium to grow healthy fruit.Tomatoes do best in soil with a pH between 6.2 and 6.8.In this articleQuick-Action ChecklistWhat Causes Blossom End Rot?Calcium ImbalanceInconsistent WateringFast Growth and High TemperaturesSpotting the SignsWhat You Can Do—Fast Fixes and Long-Term Solutions1. Water Consistently2. … Continue reading Why Your Tomatoes Are Rotting on the Bottom (And How to Fix It Fast)