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Saturday, June 24, 2023

Calcium Deficiency of Tomato and Blossom End Rot

Q. I wanted to ask about a strange occurrence in my tomato garden. Not all, but some of my tomatoes when they ripen, have these black spots only at the bottom of the tomato crop. I just wanted to reach out and see if you could tell me about what causes or could be causing the discoloration?

Blossom end rot of tomato

Blossom end rot of pepper

A. That is normally a physiological problem on tomatoes, peppers and some eggplant this time of year called blossom end rot. Some scientists claim it is caused by an imbalance of calcium in some of the fruit when soils are cooler. Sometimes calcium sprays can fix it. Some varieties of tomatoes show this problem more than others. This imbalance of calcium in other plants is called "bitter pit" in susceptible apples like 'Mutsu' and "corky spot" in susceptible pears like 'Comice'.

Bitter pit of 'Pink Lady' apple

Corky spot of  'Comice' pear

            Apples and pears take regular leaf sprays of calcium as a temporary fix in them. The easiest way to fix this problem in tomatoes is to use a less susceptible variety to blossom end rot. Otherwise, it may take several sprays of a liquid calcium spray (such as calcium chloride or calcium sulfate mixed in water) to fix it. The fruit is okay to eat, it just looks odd.

1 comment:

  1. This year, of the large amount of my watermelon harvest, I had 5 melons with end rot. I did not see this until picking time since the vines hid the melons from sight.

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