Gray wall or blotchy ripening is a name that is indicative of the disorder where fruit does not ripen properly or ripen unevenly. Symptoms develop while the fruit is still green. This condition is only found on the fruit and not on the plant.
Affected green fruit, have large, grayish or yellowish hard blotches on the fruit. Only when the fruit is over-ripe do these areas ripen – if they ripen at all. Ripe fruit have brown or green areas on the inside of the fruit walls. The outer walls of the fruit tend to be the most affected, which is obvious once the fruit are cut.
Symptoms often develop in the middle of plants which are dense and have lots of foliage and also on plants which are growing in compacted soils. Stressed and unhealthy plants also add to the problem.
A higher incidence of this condition is found in cool, wet, cloudy conditions. Because of these conditions, the fruit do not ripen properly and "veins" develop on the inside walls of the fruit. It is these areas that always remain dark green and seldom ripen. Some people also believe that the accident is affected by the nitrogen: potassium ratio of the fertilizer program, however this is not yet substantiated.
Good growing conditions will help to prevent the problem. Ensure that plants receive adequate fertilizer and regular / even watering; And check that the soil is not compacted around the roots. Tomatoes should be grown where they receive full sun and are not heavily shaded.