19+ Tomato Plant Leaves Turning Purple And Dying. Phosphorus deficiency is sometimes confused with nitrogen deficiency, it is uncommon, but does occur in areas with excessive. The most common reason this occurs is a phosphorus deficiency.
This disease starts with the tomato plant leaves turning yellow and will continue to wilt even if you are watering sufficiently.
Growing tomatoes in peatmoss/pearlite mixture/plant leaves turn purple/yellow/stem rot appears at leaf joint/gurdles stem/plant dies. Severely infected leaves turn brown and fall off, or dead, dried leaves may cling to the stem. Planting tomatoes in cold soil may cause the leaves to turn purple from a lack of potassium because tomatoes cannot absorb potassium if the soil is too cold. The lower leaves on a large, bushy, mature plants may display brown spots, might not receive.