Q: I have heard that calcium chloride is the fix for tomato blossom end rot. If this is true, could you please tell me the mixture I should use?
A: Blossom end rot accurately describes the large tan or black spot that occurs on the bottom of tomatoes and peppers. It is the result of calcium deficiency in the young fruit. Calcium deficiency may result from insufficient calcium in your soil or an inability of plants to take up sufficient amounts of the mineral. Because calcium is not a highly mobile element, changes in water availability, even for a day or two, can result in a deficiency. No fungi, bacteria, or any other disease organisms are known to cause the condition and it is not spread from one plant to another.
Calcium is absorbed through plant leaves so the best quick fix is to spray tomatoes with a calcium chloride solution. Pre-mixed sprays are available at garden centers.
You can also mix two level tablespoons of calcium chloride powder in a gallon of water. Calcium chloride (80% concentration) is the ingredient of DampRid Closet Freshener(tm) product sold at drugstores. (Use of DampRid in this way is solely the responsibility of the gardener.)
Apply three sprays at one week intervals. Lastly, be sure to mulch your tomatoes and keep the soil around them moist but not soggy during the growing season.