37+ Tomato Plants Turning Yellow. Sometimes this can not be helped due to mother nature. Rather than watering lack of important nutrients like nitrogen, or diseases could be to blame here.
The species originated in western south america and central america. Do you just have poor soil? The most common reason that tomato plants turning yellow is because of watering stress.
I don't even have any tomatoes on them yet.
Also tomato leaves can yellow at the bottom due to over watering. Ask your nursery for a fungicide (or if something else is causing yellow leaf in your area). If water remains insufficient or with repeated wilting. One question is about curling leaves, another is about the leaves turning yellow.