Blossom end rot happens not just with tomatoes, but also with peppers, squash and watermelons. There are a number of reasons for blossom end rot, all of which start because the plant has an inability to obtain calcium from the soil or the soil is deficient in calcium.
Blossom end rot is a sunken, dark area on the blossom end of the fruit, at the end opposite the stem. As the fruit develops, the rot area enlarges and can grow mold in the damaged area.
A number of factors can contribute to blossom end rot, in addition to calcium deficiency. These include irregular watering, soil mineral imbalance, root damage, broad temperature swings, or even high soil salt content. To compensate for some of these, deep water regularly instead of lightly watering daily; mulch to keep moisture in the soil; avoid high nitrogen foods that encourage foliage growth but not flower growth; avoid using fresh manure (once the plants are in the garden) because it is high in salt content.
Most important of all is the lack of calcium in the soil. To prevent blossom end rot: Start out by incorporating lime into the soil mixture before planting and feed your vegetables regularly with a vegetable food high in calcium such as Espoma Garden Tone. [insert a picture of this product] On plants showing existing symptoms of blossom end rot, visit Abby’s Parkside Nursery to purchase “Rot Stop” and spray the foliage and fruit.