Causes of Yellowing and Drying Leaves in Tomato Plants After Fruit Set and How to Prevent and Treat Them

Tomato leaves turning suddenly scorched yellow and withered during fruiting?Don't panic! Let's talk about the causes+the matching symptoms.

1. Improper Watering
 
Waterlogged roots rotting: the potting soil stays wet for a long time, the roots are deprived of oxygen and rot, the old leaves turn yellow first, spreading from the bottom upward, feeling soft and mushy to the touch, and in severe cases the whole plant wilts.

Drought and lack of water: if you forget to water for a long time, the leaves wilt and curl first, the leaf edges gradually dry out and turn yellow, feeling crisp when pinched, especially the new leaves at the top.

Remedy: for waterlogged soil, take the plant out of the pot right away and let the roots dry, cut off the rotten roots and replace with dry soil; for drought, slowly water thoroughly along the edge of the pot, and don't pour ice water directly, which shocks the roots.

2. Nutrient Deficiency
 
Nitrogen deficiency: old leaves turn yellow evenly, gradually becoming paler from the leaf tip to the leaf base, and the plant grows short and stocky, bearing less fruit.

Iron deficiency: the leaf tissue of new leaves turns yellow, but the veins stay green, like"yellow netting", while the old leaves at the bottom are temporarily normal.

Magnesium deficiency: the areas between the veins of old leaves turn yellow, but the leaf edges and leaf tips stay green, and in severe cases the yellow spots expand and merge into one patch.

Remedy: for nitrogen deficiency, water with some fermented soybean cake liquid; for iron and magnesium deficiency, you can spray foliar fertilizer, such as chelated iron or magnesium sulfate solution, which is absorbed faster.

3. Disease Infection

Leaf mold: irregular yellow spots appear on the upper surface of the leaves, and when you turn them over there is a gray or brown mold layer on the underside; when the humidity is high the mold layer thickens, and the leaves gradually curl and dry out.

Viral disease: the leaves not only turn yellow and shrivel, they also become deformed (for example, the leaves become narrow and twisted), the new leaves grow small and yellow, and the fruit may also be deformed.

Remedy: for leaf mold, spray with carbendazim or thiophanate-methyl; for viral disease, pull out the diseased plants promptly to avoid spreading, and spray antiviral agents around them for prevention.

4. Pest Infestation

Spider mites: the undersides of the leaves hide dense swarms of tiny insects, there are pinprick-sized yellow-white spots on the leaves, and in severe cases fine webs form, and the leaves turn yellow and drop off.

Whiteflies: the undersides of the leaves gather small white flying insects that fly away at a touch, the leaves turn yellow and curl, and they may also leave black secretions that cause sooty mold.

Remedy: for a small number of pests, rinse the undersides of the leaves with clean water, or wipe them with soapy water; for severe cases, spray imidacloprid or abamectin, and remember to spray the undersides of the leaves too.
 
5. Environmental Problems

Insufficient light: if kept in a dark place for a long time, the new leaves become tender yellow and whitish, the stems grow thin and long (legginess), and after fruiting the plant tends to lodge because it cannot support itself.

Abnormal temperature: a sudden drop in temperature (below10°C) or high temperature (above35°C), the leaves turn yellow irregularly, metabolism is disrupted, and the edges may even become scorched, and plants bearing a lot of fruit are especially sensitive.

Remedy: move it to a place with plenty of light (at least6hours of light per day), cover it with a bag to keep it warm when the temperature is low, and shade it and ventilate when it is hot.
 
6. Potting Soil Problems

Soil compaction: the potting soil is rock hard, water drains slowly after watering, root respiration is blocked, the leaves of the whole plant gradually turn yellow, it cannot absorb nutrients, and it grows weak and spindly.

Soil salinization: a white crust forms on the surface of the potting soil, there is an unusual smell after watering, the leaf edges become scorched and brown, spreading from the old leaves, and the new leaves also grow poorly.