The Mystery of the Nosy Tomato (2025)

Posted on September 18, 2016 by Debbie Rea - The Gardener Wife

One of the tomatoes in my garden this year developed a pointy little protrusion.I must confess that I did not give it much thought until a friend recently reported the same thing happening to her: “My tomato has a nose! Fellow gardeners, have you ever seen this before! Just curious if anyone knows how it got that way. (I don’t.)”.

Being a master gardener, I felt honor bound to look up the answer. My master googling skills turned up a gardening post with this quotation from Joe Kemble, Extension Specialist Professor at the University of Auburn.

It is a physiological/genetic disorder. With tomatoes, you can expect about 1 genetic mutation for every 1,000 plants. That’s actually a very high number.

The images with the pronounced horns resulted from a problem that occurred while the fruit was still microscopic. A few cells divided wrong and produced a extra fruit locule. Usually when you slice a fruit in half horizontally, you see 4 or 6 distinct segments in large fruited tomatoes. These are the locules. The error that occurred during cell division gets magnified as the cells increase in number and in size. The environment is the usually culprit causing the genetic problem. Usually extended high temps (above 90 during the day and above 82-85 during the night) causes the development of malformed fruit. You might only see one or two fruit on an occasional plant. Older heirloom types are more susceptible.

As day and night temps moderate, you should see fewer and fewer of these.

This explanation certainly fits our circumstances here in the southwest suburbs of Chicago. We did have a heat wave or two–that’s pretty typical–and my tomato in the above picture is an old heirloom variety, Amish Paste.

I highly recommend Amish Paste tomatoes, by the way, if you like to make sauces for freezing or canning. They grow much larger than my other paste tomatoes, Ukrainian Pear and San Marzano. Ukrainian Pear is my sentimental favorite, of course, because I am Ukrainian. Its plants are strong and prolific, so I get a lot of fruit for sauces from them even though I often have to cut off their yellow shoulders. The San Marzanos are tasty even though mine are not and cannot ever be official D.O.P. San Marzano tomatoes. Alas, they tend to be less prolific and more disease susceptible than the other varieties. (Here’s a fun story, by the way, for any cooks out there who are concerned about the quality of the canned tomatoes they use: The Mystery of San Marzano.)

And thus I’ve solved the Mystery of the Nosy Tomato.

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