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Yellow Colouring on Tomatoes

yellow shoulder disorderThe Amish Paste tomatoes that I am growing are showing a bright yellow colour at the top of the fruit.

After a search on the internet I found out that this is Yellow Shoulder Disorder. The fruits do ripen but stay yellow (or green) at the top of the fruit. At first I thought it was some kind of insect or fungal problem …but it isn’t.

Heat and Soil

It seems to be caused by extreme heat and/or poor soil conditions. Yellow shoulder disorder can be prevented by changing the soil pH and adding organic matter to the soil.

Also, tomatoes grown on soils with a high potassium level are less likely to suffer from yellow shoulder disorder. Crop rotation, shielding the plants from the sun on the hottest days, soil testing before planting out and using a feed especially for tomatoes (with a higher potassium level) will all help to produce healthy tomatoes and prevent yellow shoulder disorder.

Still Edible

The ripe tomatoes are still edible although the yellow part has lost its nutritional value and flavour.  There is nothing I can do for this year’s crop but use the tomatoes to make roasted tomato sauce.

After the season is over I will add loads of organic matter and test the soil before planting out and starting over again next year.

4 thoughts on “Yellow Colouring on Tomatoes

  1. Yes the tomatoes are completely edible and delicious, we are just used to *perfect* store bought produce. Simply cut the yellow part off, the rest of the fruit will be fine. Taste and nutrition are more important than looks, and nothing beats fresh, home grown for both. Great post for anyone who is new to gardening and concerned about this.
    Melody recently posted…Apricot Chicken BreastsMy Profile

    1. Thanks for the comment Melody, I agree that homegrown produce taste so much better. With the right soil conditions my tomatoes will taste even better next year!
      Laila Noort recently posted…Yellow Colouring on TomatoesMy Profile

  2. I’ve always wondered about this and probably let some tomatoes stay of the vine longer than they should have because of it. Thanks for the super useful info / tip.

    1. Thanks Michael, I am also glad I found out the problem. It seems that some seeds are more susceptible to yellow shoulder disorder then others so I am pretty sure you must be safe with your heirloom seeds 🙂
      Laila Noort recently posted…Dew on Straw Bale – Wordless WednesdayMy Profile

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