CO-Horts Blog

Monday, September 18, 2017

Tomato Uh-oh!

Posted by Mary Small, State Master Gardener Coordinator
No, this isn’t a new game – the title comes from something my kids would say when they were little. It usually meant that something (usually not good) just happened.

Our tomatoes had some uh-ohs this season that produced (in addition to delicious fruit!) lively discussion and internet searches for information. We grew a few hybrid varieties and one heirloom that produces beefsteak tomatoes. Of course, I failed to write down the name and the writing on the tag has faded. I think it might be Black Krim, though. It was the variety with the most interesting symptoms.
Catfacing (Forestry
  Catfacing – this is a cute name for distorted fruit that results from abnormal development of female flower parts. It can be caused by low temperatures during flowering (below 58 degrees F) and 2,4-D. In addition, beefsteak and some heirloom types are genetically more susceptible. At the front end of the season and now late in the season, cool temps at flowering certainly could have happened. But the only cause for this in mid- summer that makes sense is the cultivar and type of fruit.


Zippering –This one is caused by the male flower parts (anthers) sticking to the developing fruit. Cool weather during fruit set and genetics can play a role.

 Concentric growth cracks – this happens when the insides of the tomato grow faster than the skin. The skin can’t keep up with the interior tissue expansion so it cracks or splits. It can be caused by extreme fluctuations in water and temperature as well as genetic susceptibility. Any of these three causes could have figured in this season – but only the heirloom has the problem. 
Concentric growth cracks

Green or yellow shoulder
Green (or yellow) shoulder – the tomato "shoulders" (the stem end of the fruit) stay green or yellow and hard. Adverse tomato growing weather, soil nutrition and genetics (again!) are possible causes – but the exact reason hasn’t been determined.  Only one hybrid variety had this symptom.

Psyllid nymphs

  Psyllids –These were thankfully NIMG – not in my garden - although I have dealt with them other years. The insects feed on sap and inject toxic saliva into the plant. This stops growth, stunts leaves and causes them to turn yellow and/or purple. Tomato fruit is abundant – but tasteless. The little stinkers aren’t easy to find until you a) check the undersides of leaves for the nymphs or b) find what looks like sugar or salt accumulating on leaves, stems or the soil underneath plants. While there are insecticides available– and sulfur works well – it may be too late depending on when you discover the problem.

This has been one of the most entertaining, educational and delicious tomato years we’ve had in a long time. Can’t wait for next years’ adventures!


  1. I gave up trying to grow tomatoes. They never look good.

  2. I've found my greatest success growing cherry tomatoes. I'm terrible at consistent watering, so the larger 'maters always get blossom end rot. Smaller tomatoes don't seem as susceptible, which is good! I had a bumper crop of Sungold this year, thoroughly enjoyed by my coworkers.

  3. Nice article great post comment information thanks for sharing


  4. I had the same problem with Black Krim. I also grew Sun Sweet. Stupice, and Early Girl. All of those were fine and they are smaller varieties.

  5. I grow mostly heirlooms. I had 42 tomato plants of which 3 varieties were not.
    I had great success with all but about 4. I have eliminated the following for next year: Sioux, Japanese Black Trifle, Matina,Opaika and didn't really like the Black Krim or the Black from Tula. They either didn't produce well, plant died, small fruit, tomatoes didn't look good to eat.

  6. Allison, you should try Mexico Midget. They are half an ounce each but packed with flavor. Grow like a weed too. I saved some seeds to grow next year.