I noticed the lower leaves of my tomato plants were browning. With further inspection, I noticed the leaves had spots.
Tomatoes can get several diseases so proper identification is crucial before any action is taken.
My tomatoes are suffering from leaf spot diseases which can include septoria leaf spot and early blight. Both cause spots and can cause the leaves to quickly yellow and drop, starting at the bottom of the plant. Septoria causes small water-soaked spots. These spots become circular to angular with dark margins and grayish white centers. Early blight causes small brown leaf spots with a target-like series of concentric rings in each lesion.