A  rotting spot on the end of tomatoes is called blossom end rot.  It is very common on tomatoes, peppers, and watermelons.  This is caused by a lack of calcium in the plant.  It is a physiological disorder not a disease.  When fruits are growing rapidly, sufficient amounts of calcium fail to reach the end of the fruit, resulting in a deficiency of calcium in the developing fruit. 

Blossom end rot begins as a small, water soaked spot.  The spot develops into a dark brown, leathery area on the bottom end of the fruit.  The surface of the spot shrinks and becomes flattened or sunken.  This disorder is most severe following fluctuations in soil moisture (either too dry or too wet).  Remove the affected fruit when the symptoms are first observed will help to promote the good development of healthy fruit.

Well, how do we fix this issue?  One way is to use calcium nitrate.  Calcium nitrate is a fertilizer containing 2 important nutrients that plants need, calcium and nitrogen.  Some use it when planting the tomatoes and others use it after the rot starts.  One teaspoon per each plant applied to the root growing area of the plant is the rate of use.  Do not apply within 2 inches of the plant stem.  Water in after the application.  Another application is recommended in 2 weeks.  Only make applications in the cooler part of the day.  

Another calcium additive is to use milk or a tums tablet.  This is adding the calcium needed to the plant.  They most likely won’t work as fast as the calcium nitrate.  Also mulching and irrigation will help to prevent this condition.  After the years crop has finished you might want to take a soil sample to check the ph of the soil.  Liming the soil if needed will help as well.  

So, lets get ready for the BLT sandwiches with the beautiful tomatoes that you grew yourself.  Don’t forget to plant some extra for the neighbors.