Blossom-end rot is the result of a plant’s inability to have a continuous, regular supply of calcium. It often occurs on tomatoes and other vegetables. Calcium intake is regulated by the amount of moisture in the soil. Rotting occurs at the end of the vegetable opposite the stem.
Avoid planting when the soil is still too cold.
Remove all affected fruits at the first sign of blossom-end rot.
Fertilizer
Avoid using excessive high-nitrogen fertilizer, like fresh manure, to prevent rapid plant growth.
pH Level
To enable the plant’s vascular system to absorb nutrients properly, maintain a soil pH level of approximately 6.5 to 6.7.
Cultivating
To avoid root injury, don’t cultivate deeper than 1 inch near the base of the plant.
Mulch
Maintain uniform soil moisture by watering plants during dry weather and mulching them to retain moisture. Mulching will also keep weeds away.