|Why are the leaves turning yellow on the bottom of the tomatoes?|
When lower leaves turn yellow it is usually a sign of temporary droughty soil conditions or of a lack of nitrogen. If nematodes are infesting the root system the plants may also exhibit such symptoms. Nematodes are primarily a problem in sandy soils. They are best managed by planting resistant varieties of tomatoes (those with an "N" after the variety name, such as Celebrity VFN).
Thanks for the question and please let us know if we can be of more assistance!