Answer: There are a few explanations for your problem of half-ripe tomatoes. First of all, some tomato varieties--especially heirloom types--are more susceptible to this problem than others.
During the ripening process, chlorophyll breaks down and the fruit softens and turns red. However, in some varieties, during periods of high temperatures and/or in direct sun exposure, the chlorophyll doesn't break down normally and the exposed side stays hard and green.
You can try picking the tomatoes when they are still quite green, and ripen them indoors out of direct sunlight. Also, try to maintain good foliage cover--the problem will be worse on plants that have been defoliated by disease or insects.
Wilting might be caused by insufficient water, or by a disease. The two most devastating problems attacking tomato plants are early blight and late blight. Early blight is caused by the fungus Alternaria. It begins with small spots on the lower leaves and progresses to the stems. The spots sometimes take on a bulls-eye appearance. Regular use of the fungicide lime-sulfur (Bordeaux) will help protect your plants. Late blight is caused by the fungus Phythopthora, and cool, wet conditions favor the development of this disease. The affected plants respond to regular fungicides sprays that include copper. Be sure to plant your tomatoes in a different spot in the garden this year to avoid any soil-borne pathogens from last year. Always remove and destroy any affected plant parts. And, if you use fungicides, always read andfollow the label directions.
Q&A Library Searching Tips