15 Reasons Why Tomato Leaves Turn Yellow

During the process of growing tomatoes, improper management can easily lead to various problems, which will have a great impact on the growth and development of tomatoes. Here are 15 reasons why tomato leaves turn yellow.

1. Repeated cropping

Tomatoes are most likely to develop tomato diseases when they are cultivated continuously for a long time. The symptoms include yellowing of the leaves, especially the lower leaves, which are prone to yellowing and drying up. The lateral roots and fine roots will gradually rot, and the taproot will gradually turn brown and the epidermis will become deformed. Avoid planting tomatoes in the same crop over and over again.

2. Nitrogen deficiency

When tomatoes are deficient in nitrogen, the leaves in the middle and lower parts of the plant will turn yellow first, the leaves will become smaller, and the number of tomato fruits will also decrease. This is a symptom of nitrogen deficiency. If there is a nitrogen deficiency, a quick flush of nitrogen fertilizer should be applied.

3. Phosphorus deficiency

When tomatoes lack phosphorus, the leaves become smaller and purple-red appears on the veins. This physiological disease is mainly caused by phosphorus deficiency. You can supplement it through the leaves, such as using foliar fertilizers such as superphosphate and potassium dihydrogen phosphate. It is generally recommended to spray it 2 to 3 times continuously.

4. Potassium deficiency

When tomatoes are deficient in potassium, the leaves, especially the edges of the middle and lower leaves, will turn brown and begin to die. If the situation is serious, a large amount of leaves will fall. When the plants are deficient in potassium, in addition to normal water and fertilizer management and supplementary potassium fertilizers, we also apply potassium sulfate and potassium nitrate.

5. Water accumulation

If tomatoes are overwatered during their growth process, it will lead to poor growth and yellow leaves. Do not let water accumulate in the soil each time you water, and maintain good drainage.

6. Root rot

If you find that the leaves at the bottom of the tomato rhizome become tender and yellow, it is caused by root rot. Once the root rot becomes serious, the plants with rotten roots need to be dug up and the surrounding soil needs to be dug up and discarded.

7. Soil caking

Poor soil permeability and loose soil can easily cause tomato leaves to turn yellow. When planting tomatoes, you can add some decomposed manure under the soil, or regularly add some organic fertilizer water during the tomato's growing season in spring and summer, which will help prevent the soil from clumping.

8. Leaf spot

Tomato leaf spot disease is easy to breed in an environment with moist soil or extremely high air humidity. It can also occur if the maintenance location is poorly ventilated or the tomatoes are not properly grown on a shelf. All you need to do is cut off the yellow leaves and spray fungicides in time.

9. Fusarium wilt

Fusarium wilt is a common fungal disease, usually caused by the fungus Fusarium oxysporum, which causes plants to wilt. To prevent wilt, keep the soil acidic and regularly irrigate the soil with fungicides, such as carbendazim solution.

10. Lack of nutrition

If the soil becomes alkaline, the leaves will easily turn yellow. Don't always use tap water to water the tomatoes. Occasionally add some organic fertilizer water to help prevent the leaves from turning yellow and allow the plants to grow healthily.

11. Excessive use of fertilizer

Some farmers spread too much fertilizer on the soil, or the fertilizer evaporates under high temperature conditions, producing gas that burns the leaves and causes yellow leaves.

12. Drug damage

Leaf burn is caused by farmers' unreasonable mixing of pesticides when spraying, or the wrong dosage form and concentration of pesticides . When mixing pesticides, foliar fertilizer, wettable powder, suspension concentrate, aqueous solution and emulsion should be added in sequence. Each time one is added, stir it thoroughly before adding the next one.

13. High planting density

Tomatoes were planted densely in the field and the lower leaves showed yellowing. This situation is mostly caused by insufficient light and poor airtightness. Pay attention to the density when planting, and control the plant spacing to about 40 cm.

14. Watering at high temperature

When farmers water the plants under high temperatures, if the amount of water applied is too large or the field humidity is too high, it may also cause yellowing leaves of tomatoes. Excessive watering will affect root growth, resulting in insufficient nutrient absorption and supply, and some leaves will show yellowing. When watering in hot and dry weather, farmers are advised to use small amounts of water and water frequently according to the soil moisture conditions.

15. Drought and water shortage

When planting tomatoes, if drought occurs, the tomato leaves may turn yellow, especially the lower leaves. Long-term dehydration may cause the leaves to lose their green color and age. Remember to stay hydrated.

That’s it