Tomato Grey Wall

Are your tomatoes ripening unevenly? When you cut into them, do the walls look gray? It’s probably tomato gray wall. Also known as graywall and blotchy ripening, this disorder occurs when environmental conditions are less than ideal.

Tomato with gray wall (Edward Sikora, Auburn University, Bugwood.org) CC BY 3.0 US

[Sorry, but there were very few photos available for use, but you can search online to get a better idea of what this condition looks like.]


Tomato gray wall symptoms

While the rest of your tomato plant looks fantastic, with sturdy stems and lush leaf growth, tomatoes affected with graywall ripen unevenly with both red and yellow areas. This yellow mottling starts appearing while the fruit is green. As the fruit matures, these areas can turn grey and become sunken. These symptoms are not the same as yellow shoulder. When tomatoes develop yellow or green shoulders, they have been exposed to too much heat and sunlight, and symptoms are limited to the upper portions of the fruit. Tomato gray wall can be seen all around the fruit.


If you cut open an affected tomato, you will see that the walls of the fruit are gray, yellow, brown, or green. Anything but red. If you look closely, you might also see that the vascular tissue has turned dark brown. If the rest of the plant looks affected, it is probably tomato mosaic virus.


Tomato gray wall causes

Several conditions can cause gray wall in tomatoes. Some of them you can change and some of them you can’t. Extreme heat, fluctuating temperatures, and high humidity can stress plants into responding with gray wall. Overcast skies during hot weather, fog, and excess shade can also cause blotchy ripening. Overly wet soil or compacted soil can also cause tomato graywall. Too much nitrogen, or not enough potassium or boron can lead to tomato gray wall. [Have you tested your soil lately?] Scientists also believe that some bacteria, fungi, and the tomato mosaic virus part of the problem, but they’re not sure how.


Tomato gray wall prevention

You can prevent tomato gray wall by providing good drainage and improving soil structure, planting varieties that are resistant to tomato mosaic, and feeding your plants appropriately.