I apologize for this delayed reply to your gardening question. The spring rush has brought a deluge of questions and we are working hard to catch up!
When lower leaves on a tomato turn yellow and then brown it is usually due to a root problem or a leaf disease. Root problems include droughty conditions and soil fungal wilts. Leaf diseases like early blight can also have the same effect and can be remedied with fungicide sprays of mancozeb or maneb.
Thanks for the question. Best wishes for a wonderful gardening season. Please stop in again soon!
Q&A Library Searching Tips